LEKKING BEHAVIOR OF THE ROUND-TAILED MANAKIN

[298]

The Condor 103:298–321q The Cooper Ornithological Society 2001

LEKKING BEHAVIOR OF THE ROUND-TAILED MANAKIN1

JOSE G. TELLO2

Department of Biology, University of Missouri-Saint Louis, 8001 Natural Bridge Road,Saint Louis, MO 63121-4499

Abstract. Along the Rio Manu in southeastern Peru, Round-tailed Manakins (Pipra chlo-romeros) breed mainly from August to November. Male P. chloromeros have a dispersedlek breeding system, with each lek composed of two to five territorial males. Sites used bymales for display had significantly higher densities of shrubs, vines, and small trees thandid non-display sites. Interlek distances ranged from 220 to 1000 m. Within leks, mostmales occupied territories within auditory range, but not visual range. Distance to the closestneighbor’s display perch varied from 8 to 87 m. Males vigorously defended territories thatranged from 20 to 50 m in diameter. Males progress in social status within the lek (fromimmature to non-territorial adult to territorial adult). Territorial adult males were alwaysdominant to males of the other two categories. Territorial males engaged in daily ritualizedencounters at the borders of their territories. Encounters involved slow, coordinated displaysreminiscent of those performed toward females. Such interactions may help maintain dom-inance relationships within the lek, but an analysis of interaction outcomes failed to showclear dominance relationships among males. Female visitation was most frequent in earlyafternoon, during males’ maximum territory attendance and display activity. Lekking P.chloromeros employ ten display elements, six vocalizations, and one mechanical noise. Onedisplay element has not been observed in any other species of Pipra. The displays andsounds in the P. erythrocephala clade are compared from the perspective of understandingthe evolution of display behavior in this group.

Key words: courtship, display, lek, manakins, Pipra chloromeros, social organization,song.

El Comportamiento de Lek del Saltarın de Cola Redonda

Resumen. El comportamiento de lek del Saltarın de Cola Redonda (Pipra chloromeros)fue estudiado en el Rıo Manu, sudeste del Peru. Esta especie tiene un sistema de leksdisperso, con leks compuestos de 2 a 5 machos territoriales. Las areas de despliegue tuvierondensidades significativamente altas de arbustos, lianas y arboles pequenos, en comparacioncon areas sin leks. La distancia entre leks vario de 220 a 1000 m. Dentro de los leks, losmachos defendieron territorios de 20 a 50 m de diametro. La distancia entre territorios variode 8 a 87 m. Los machos experimentan una progresion en status social dentro del lek(machos inmaduros, machos adultos no-territoriales y machos adultos territoriales). Los ma-chos territoriales mantuvieron encuentros diarios altamente ritualizados en los lımites de susterritorios. Estos encuentros incluyeron elementos del despliegue de cortejo, aunque de masbaja intensidad. Estos encuentros servirıan para mantener las jerarquıas sociales dentro dellek. Sin embargo, un analisis de los resultados de estas interacciones no mostro un patronclaro de dominancia. Las visitas de las hembras coincidieron con las horas de maximaatencion del territorio y el pico de actividad de despliegue. El repertorio de despliegue deesta especie incluyo diez elementos de despliegue, seis vocalizaciones y un sonido mecanico.Uno de estos elementos no ha sido previamente descrito para ninguna otra especie de Pipra.Los despliegues, vocalizaciones y sonidos mecanicos presentes en el clado de P. erythro-cephala son comparados con la perspectiva de entender la evolucion del comportamientode despliegue en este grupo.

INTRODUCTION

Manakins (Pipridae) are among the most color-ful small passerine birds of the Neotropics, with

1 Received 24 February 2000. Accepted 21 Decem-ber 2000.

2 Present address: Department of Zoology, The FieldMuseum, 1400 S. Lake Shore Drive, Chicago, IL60605–2496, e-mail: [email protected]

the majority of species exhibiting marked sexualdimorphism, elaborate courtship displays, andlek breeding systems (Snow 1963a, Sick 1967,Prum 1990, 1994). The social organization ofleks is of particular interest to ethologists be-cause lekking so strikingly epitomizes the con-flict between advantages (e.g., more females at-tracted, decreased predation risk) and disadvan-tages (heightened competition and aggression)

LEKKING BEHAVIOR OF THE ROUND-TAILED MANAKIN 299

FIGURE 1. (a) Geographic distribution of Pipra chloromeros and location of the study site, Cocha CashuBiological Station (CCBS), on the Rio Manu, Peru (black dot). (b) Distribution of Pipra chloromeros leks (blackdots) at mature floodplain and terra firme forest around CCBS.

inherent in a highly social mode of life (Alex-ander 1974). A presumed function of social or-ganization within such species is resolution ofthis conflict through amelioration of the disad-vantageous effects of social life. This is partic-ularly true of tropical lekking species with ex-tended breeding seasons, like those of Pipraspp., in which males spend most of their wakingadult life very close to other males at leks (Snow1962, Lill 1976, Robbins 1985).

Prum’s (1990, 1992, 1994) comparative stud-ies of the manakins demonstrate that lek breed-ing evolved early in the Pipridae, and that manyaspects of the display and reproductive behaviorvary phylogenetically among closely relatedgenera and species of manakins. Althoughsomething is known about the courtship behav-ior of more than half of the family’s 40 species,some have not yet been studied. Additional work

on the poorly known species is essential to ad-vancing our understanding of the evolution ofbehavior in the family (Prum 1996).

In this study, I report on lekking behavior ofthe Round-tailed Manakin (Pipra chloromeros).Our understanding of behavior in this manakinis limited to some notes of Niethammer (1956)and unpublished observations cited in Prum(1990). Pipra chloromeros is found in humidforest, both in upper tropical and lower subtrop-ical zones (300–1400 m) from eastern Peru(Dpto. Amazonas and San Martin) to northernBolivia (Dptos. La Paz, Cochabamba, and west-ern Santa Cruz) (Snow 1979, Ridgely and Tudor1994; Fig. 1a). Based on morphology and zoo-geography, P. chloromeros is closely related tothe Scarlet-horned (P. cornuta), Red-capped (P.mentalis), Red-headed (P. rubrocapilla), andGolden-headed (P. erythrocephala) Manakins

300 JOSE G. TELLO

(Haffer 1970, Prum 1990, 1992). These five spe-cies comprise the P. erythrocephala clade (Prum1992).

My goal in this study was to document thesocial and reproductive behavior of this poorlyknown species. My objectives were (1) to deter-mine abundance, spatial distribution, and socialstructure of P. chloromeros leks; (2) to describeand quantify characteristics of the habitat se-lected by males for display sites; (3) to describesocial organization and courtship behavior; and(4) to compare the display behavior amongmembers of the P. erythrocephala clade.

METHODSSTUDY SITE

Observations were conducted in an undisturbedlowland wet forest at Cocha Cashu BiologicalStation (118549S, 718189W, elevation ca. 400 m,Fig. 1a), Manu National Park, Department ofMadre de Dios, southeastern Peru. Mean tem-perature at the station is 238C to 248C, and rain-fall averages about 2000 mm annually (Terborghet al. 1990). Rainfall is concentrated during afive-month rainy season extending from late No-vember to early May. On average, less than 100mm of rain falls during the dry season.

The sinuous meanderings of the Manu Rivertransform the landscape both spatially and tem-porally. At each bend, forest on the outer sideof the river is annually undermined and carriedaway, while on the inside shore, new land is laiddown in the form of broad beaches (Terborgh1983). As a result of this riverine dynamic, anarrow mosaic of successional forest types oc-curs in the inside shore, producing distinctivevegetation zones. Forests in the vicinity of Co-cha Cashu fall into two broad categories, flood-plain (near the inside shore on flat terrain, sea-sonally flooded) and terra firme (far from theinside shore on hilly terrain, never flooded).More complete descriptions of the area and itsecology are presented by Terborgh (1983), Fos-ter et al. (1986), and Gentry and Terborgh(1990).

DATA COLLECTION

Observations were made during four field sea-sons: August to November 1989, August to Sep-tember 1990, August to November 1992, andAugust to December 1994. To determine pat-terns of distribution and abundance of P. chlo-romeros, I conducted censuses along a 50-km

trail system located in floodplain and terra firmeforests using the spot-mapping method (Ken-deigh 1944). Manakins were counted within a100-m-wide band centered on the trail. Positionsof singing males were estimated, using a com-pass, as the direction and straight-line distancefrom the nearest trail marker; markers were lo-cated at 25-m intervals on all trails. Mappingrecords of successive censuses along each tran-sect produced clusters of points that were as-sumed to represent the locations of individualterritories (courts) or clusters of males. I latervisited these locations to determine whether alek was present. I completed 210 hr of censusesin floodplain forest and 130 hr in terra firme for-est between 1989 and 1994. Censuses covered atotal area of approximately 7 km2 in floodplainand 1 km2 in terra firme forest. Censuses wereconducted from 06:00 to 10:00 and from 12:00to 15:00.

Interlek distance was measured as the distancefrom the center of one lek to the center of thenearest conspecific lek. Number of territorialmales per lek and locations of adult male displaycourts were determined by direct observation. Atsome leks, where males were individually color-banded, I mapped the locations of all the perchesused by each territorial male. Then, court sizefor each male was drawn on a map using themodified minimum-area polygon method (Har-vey and Barbour 1965), and the area was mea-sured using SigmaScan/Image measurementsoftware (Jandel Scientific 1993).

Characteristics of the habitat used by P. chlo-romeros were quantified at six display sites in1989 and two in 1994. Vegetation samples fromcontrol areas (13 randomly selected places with-in the same types of forests used by the mana-kins) were compared with samples made at thecourts. Data from randomly selected controlsamples were provided by Dr. M. Foster (U.S.Geological Survey, Biological Resources Divi-sion, Washington, DC). The sampling methodwas a modification of the James and Shugart(1970) method of vegetation analysis. A circularplot of 11.3-m radius was located approximatelyat the center of the court or sample area. Twotransects of 22.6-m length, oriented east-westand north-south, were established within eachcircle. In these transects, 10 and 11 points, re-spectively, were used to estimate relative vege-tation cover (both ground and canopy) using acardboard tube with two threads crossed over


one opening. These lines divided the field ob-served into four cells. At each point, the numberof cells in which at least 50% of the area wascovered by vegetation was recorded by lookingstraight up at the canopy and straight down atthe ground. Density of woody shrubs and sap-lings (,7.5 cm diameter at breast height [dbh])was measured by walking N-S and E-W tran-sects with arms outstretched and counting allstems encountered, including woody vines andpalms, (i.e., plants $1.5 m tall). Number oftrees, including large palms, with dbh $7.5 cmwas recorded for the entire sample circle; treeswere assigned to size categories (7.5–10 cm;10.1–12.5 cm; 12.6–15 cm; 15.1–20 cm; 20.1–25 cm; 25.1–55 cm; and .55 cm). Two-samplet-tests were used to evaluate differences betweenmanakin display plots and randomly selectedplots for each habitat variable separately (i.e.,ground and canopy cover, density of shrubs withdbh , 7.5 cm, density of all trees with dbh $7.5 cm). Mann-Whitney U-tests were used whendata did not meet an assumption of normality.Discriminant function analysis (DFA) was usedto explore what combination of variables, if any,best distinguished habitats at manakin displayand non-display sites.

Non-structured behavioral observations of P.chloromeros leks were made from 1989 to 1992.In 1994, behavior of territorial males at two lekswas observed for a total of 360 hr using focalsampling (Altmann 1974). Every male was ob-served for an equal number of hours for a totalof three days. Five periods of observation weredistributed between 05:30 and 16:00 and lasted2 hr (the first four periods), except the fifth pe-riod, which lasted for 1.5 hr. Within each period,I conducted focal observations of 3-min dura-tion, at 15-min intervals, and recorded descrip-tions of the displays and behavior of adultmales, immatures, and females; female visita-tions and copulations; calling activity (numberof advertisement calls); display activity (numberof flight displays); interactions with neighborsand non-territorial and juvenile males; and du-ration of territory absence. Young males weredistinguished from females by their plumage (ifmolting into adult plumage), their behavior atthe lek, and the reaction of territorial maleswhen these individuals visited their courts. Forall perches used by territorial males I recordedthe following data: perch type, perch inclination(angle from horizontal), height, diameter, and

height of the nearest vegetation cover above theperch. I also recorded vocalizations and me-chanical sounds associated with displays. Re-cordings were made with a Sony TCM-5000EVtape recorder and an MK67 unidirectional Senn-heiser microphone. Spectrograms were preparedwith Canary 1.2 song analyzer software (Charifet al. 1995). To facilitate comparisons, I haveadopted, whenever possible, the terminology ofRobbins (1983) and Prum (1990) to describe vo-calizations and displays of P. chloromeros rel-ative to those of other members of the genus.Display drawings were prepared by M. Skakujusing video, photos, sketches, and verbal de-scriptions.

At the two focal leks, court boundaries of in-dividual territorial males were determined bymapping the locations of agonistic encountersbetween pairs of neighbors (Lill 1974, 1976) andby noting movements of territorial males duringperiods of observation. Dominance relationshipswere evaluated using data from the territorial en-counters. I used number of approaches, with-drawals, and percentages of approaches causingwithdrawals to test for differences in dominancerelationships between interacting pairs. Domi-nant males were expected to approach more,withdraw less, and cause more withdrawals thansubordinate males (Lill 1974, 1976). Data werecompared using Mann-Whitney U-tests. Be-cause foliage often obscured territorial encoun-ters, the number observed was low. Thus, Ichose to analyze dominance relationships onlybetween pairs of adjacent territorial males withat least six encounters.

The effect of lek size (number of males) onfemale visitation, male success, and overall dis-play behavior was evaluated using data from thetwo leks, which included two and five males,respectively. These leks were approximately 650m apart in floodplain forest. Data on female vis-itation, number of observed copulations, visitsof immatures, calling activity (number of vocal-izations), display activity (number of flight dis-plays), and number of boundary encounters be-tween males recorded at these two leks wereused in this comparison. For the purpose ofthese comparisons, lek totals and male averages,for these variables, were calculated (n 5 3).Data were compared using Mann-Whitney U-tests. Because of the small sample size (i.e., twoleks) these analyses were primarily descriptive.Values presented are means 6 SE.

302 JOSE G. TELLO

RESULTS

DISTRIBUTION AND ABUNDANCE OF LEKS

Leks of P. chloromeros were found in both ma-ture floodplain (n 5 4) and terra firme forests (n5 3) (Fig. 1b). Interlek distances ranged from220 to 1000 m (mean 5 512 6 144 m, n 5 5).Lek density in floodplain forest was lower (0.6leks km22) than in terra firme forest (3 lekskm22). In floodplain forest, two other manakinspecies, Band-tailed (P. fasciicauda) and Blue-crowned (P. coronata) Manakins, were morecommon than P. chloromeros.

As with other lekking birds, leks were persis-tent at particular sites across seasons (Lill 1976,Foster 1981, MacDonald 1990). When I endedmy observations in 1994, at Cocha Cashu, twoleks of P. chloromeros had persisted at the samesites for at least 5 years, and four at the samesites for at least 7 years.

DISTRIBUTION OF MALE TERRITORIES ANDDISPLAY SITES

Two to five P. chloromeros males occupiedcourts on each lek. Within leks, most males oc-cupied courts within auditory range of each oth-er, but some males used display perches closeenough to also maintain visual contact. Distanceto the closest neighbor display perch averaged30.5 6 12.8 m (n 5 6). Defended territoriesranged in size from 20 to 50 m estimated di-ameter (mean 5 25.1 6 3.0 m, n 5 7). Territo-rial males gave frequent advertisement calls andaggressively excluded other males.

Individual males used between 8 and 26 dif-ferent perches in their courts. Perches were al-ways free of obstructing vegetation (twigs or fo-liage) for at least 0.5 m, leaving clear pathwaysin front of and behind the perch. Although lo-cated in areas with relatively open canopies,perches in general had thick vegetation over-head, which could provide protection againstpredation. Perches were mainly horizontal, rang-ing between 0.3 and 2.5 cm in diameter, andfrom 4 to 16 m above the ground. Averageheights of perches varied significantly amongmales (ANOVA: F6,103 5 13.1, P , 0.001), butperch diameter was consistent among males(ANOVA: F6,103 5 1.7, P . 0.05). Each malecourt included one or two horizontal displayperches, one to three accessory perches adjacentto the display perches, and from 5 to 19 adver-tising perches. Display perches varied from 0.5

to 1.3 cm in diameter (mean 5 0.9 6 0.1 cm),and 8 to 16 m above the ground (mean 5 9.8 60.8 m).

CHARACTERISTICS OF THE HABITAT USEDFOR DISPLAY SITES

Most leks were located in mature forest on flatterrain. Two leks in terra firme forests were lo-cated close to a moderately steep slope. The for-est around leks was moderately open, with anaverage canopy height of 30 to 35 m. A fewemergent canopy trees (e.g., Dipteryx micran-tha, Ficus spp.) extended to ca. 45 m. Groundcover varied from bare to moderately coveredwith herbaceous growth. A nearly monotypiclayer of ferns (Tectaria incisa var. vivipara)dominated the ground in some areas, whereas inother sites, ferns were replaced by short speciesof Heliconia (Terborgh 1983). The understoryincluded many species of shrubs and treelets thatproduce red or dark purple berries eaten by themanakins (e.g., many species of Psychotria, Mi-conia, Neea, and Ardisia). In some areas of terrafirme forest, the understory was dominated bydense patches of bamboo (Guadua sp.).

Univariate comparisons showed that sitesused by P. chloromeros males for display hadsignificantly higher densities of shrubs and tree-lets (,7.5 cm dbh and $ 1.5 m tall), vines (,7.5cm dbh), and small trees (10.1–12.5 cm dbh)than did randomly selected non-display sites(Table 1). A DFA using these three variableswas significant (P , 0.01) and correctly classi-fied 90.5% of the cases. Thus, both univariateand multivariate analyses demonstrate differenc-es between display and non-display sites. Theseresults suggest that sites used for displays areselected in part because of structural features ofthe vegetation, presumably the denser understo-ry.

DISPLAYS, VOCALIZATIONS, AND OTHERSOUNDS

The display repertoire of P. chloromeros in-cludes ten display elements, six vocalizations,and one mechanical noise. The frequency of oc-currence at which P. chloromeros males per-formed certain displays and sounds varied, butall males regularly performed a combination ofcertain behaviors (Table 2). I first describe thedisplays, and then the vocalizations and othersounds with which they are associated.

Upright posture. The male assumes a posture


TABLE 1. Mean 6 SE proportion of cover (%), den-sities (per 0.04 ha) of vegetation features, and canopyheight (m) recorded at 8 Pipra chloromeros displaysites and 13 non-display sites along the Manu river,Madre de Dios, Peru. * P , 0.05; ** P , 0.005(Mann-Whitney U-tests).

Variable Display sitesNon-display

sites

Percent coverGroundCanopy

44.0 6 5.095.0 6 1.0

35.0 6 3.097.0 6 1.0

Shrubs (,7.5 cm dbh)Vines (,7.5 cm dbh)

59.1 6 5.1**34.3 6 10.0*

38.0 6 4.08.6 6 1.5

Trees ($7.5 cm dbh)7.5–10 cm dbh

10.1–12.5 cm dbh12.6–15 cm dbh15.1–20 cm dbh20.1–25 cm dbh25.1–55 cm dbh.55 cm dbh

8.9 6 1.26.9 6 0.7*3.9 6 1.04.6 6 1.12.6 6 0.42.6 6 0.72.3 6 0.5

9.5 6 1.14.7 6 0.54.7 6 0.75.4 6 0.72.9 6 0.61.8 6 0.32.4 6 0.5

Canopy heighta 14.0 6 2.8 13.0 6 0.6

a Represents the average height of all vegetation layersat each plot.

TABLE 2. Occurrence of displays, vocalizations, andother sounds at two Pipra chloromeros leks in 1994.Percentage occurrence of each display or displaysound during focal samples was calculated separatelyby dividing the number of observations of each displayor display sound by the total number of observationsof all different types of displays (1055) or displaysounds (3112), respectively.

Displays, vocalizations,and other sounds

Percentage ofoccurrence

DisplaysTo-and-fro flightType I flight displaya

Wing-flick 1 pivotBackward slideAbout faceSquatType II flight displaya

Frenzied-fluttera

Side-to-sideUpright posture

48.613.1

9.910.7

8.97.11.30.4

,0.3,0.3

Vocalizations and other soundsAdvertisement callDisplay callAppeasement whistleDouble-wing snap

79.415.0

4.31.3

a Vocalizations associated with these displays were notincluded in the analysis.

in which the head is held nearly vertical, withthe bill pointed up. Males assume this postureduring encounters at court boundaries. It is alsothe position assumed by the female when shearrives at the display perch and the male initiatescourtship.

About-face. A male makes a rapid 1808 turnin place on a single perch between to-and-froflights. About-faces may be accompanied by arapid flick of the wings (no mechanical noiseinvolved). A slower version of this display alsooccurs during boundary encounters among ter-ritorial males.

To-and-fro flight. A male flies back and forthbetween his main perch and one or two adjacentaccessory perches 50 to 100 cm away. The maledoes an about-face immediately after landing ona perch. A displaying male sometimes gives themain phrase of the advertisement call (see be-low) immediately after arriving at a perch. Thisis sometimes preceded by the introductoryphrase, which is given in flight. Occasionally,males make a double-wing snap immediately af-ter landing on the perch. Less frequently, thismechanical sound is performed simultaneouslywith an advertisement call after landing. To-and-fro flights were the most common displays per-formed by males at the leks (48.6% of all ob-served displays) and generally occurred when a

female-plumaged bird (a female or a youngmale) visited a male’s court. This display pre-sumably functions to attract visiting birds to thedisplay area.

Squat. This display resembles the display de-scribed by Lill (1976) for P. erythrocephala.The male crouches transversely on his perchwith legs bent. He fans his tail (which enhancesits roundness) and lowers his partially spreadprimaries, quivering them rapidly, while makingrapid side-to-side jumps. Sometimes the displayends with a mechanical noise similar to the dou-ble-wing snap, a sound also produced by P.mentalis (pers. obs.), and P. cornuta (NaturalSound Archive recording 26161; R. Prum, per-sonal recordings), but not as loud. I usually ob-served this display when the male was excited,as, for example, when a female was present atthe display perch of another male, or when an-other male was present in his court. After thedisplay, the male usually abandons the displayperch and then returns with a flight display fromone of the accessory perches.

Wing-flick. This display involves several rapidflicks of the wings (no mechanical noise in-

304 JOSE G. TELLO

volved). Flicking generally alternates with piv-ots (rapid 458 turns in place on a single perch),although sometimes they are simultaneous(wing-flicks 1 pivots, see Backward slide).Wing-flicking is an element of both courtshipdisplays and territorial interactions.

Backward slide. With the body orientedlengthwise along or nearly along the perch, tailelevated, legs stretched, body feathers elevated,and head lowered, a male takes short rapid stepsbackward for 15 to 30 cm along the displayperch, giving the appearance of sliding quickly(Fig. 2a). At the end of the slide, one of thefollowing behaviors occurs: (1) With the bodystill parallel to the perch, the male raises his tailand head, adopting a ‘‘U’’ posture for 2 to 3 sec(Fig. 2b). A soft hick sound (of unknown source)accompanies this movement; (2) The male wing-flicks 1 pivots on the perch, and then suddenlyabandons the perch and returns with a flight dis-play (see below); (3) With the body oriented al-most perpendicular to the perch, the malespreads his wings horizontally for a moment,quivers them, and suddenly fans his slightly de-pressed tail (Fig. 2c–e), sometimes giving a dis-play call (Fi-cuac-cuac). Less frequently, themale just spreads his wings for a moment with-out quivering; (4) The male vibrates his wingsextremely rapidly as in the squatting display; or(5) The male makes an about-face and with thebody parallel to the perch slides backward to-ward his starting location.

Side-to-side slide. With the body oriented per-pendicular to the perch, the male takes veryshort steps (slides) back and forth for 5 to 10cm. Side-to-side slides were seen only occasion-ally, during encounters between territorial malesat their court boundaries.

Type I flight display (Swoop-in flight display).The male flies downward and then upward to ahigher perch (12–15 m high), 15 to 20 m awayfrom his display perch. After 2 to 3 sec, he re-turns to his display perch, flying rapidly andagain tracing a horizontal S-pattern in flight(Fig. 3a). A Type I flight display call is usuallygiven on landing (Fig. 4f). Immediately afterperching, the male sometimes executes one ormore backward slides (Fig. 3c) or squatting dis-plays (Fig. 3b) before leaving the perch to repeatthe display. Type I flight displays were mainlyperformed by males when females visited theirterritories, and, thus, constituted an important el-ement of the courtship of this species (13.1%,

the second most common display in the P. chlo-romeros display repertoire).

Type II flight display (Catapult-like flight).This less frequently observed flight display(1.3%) may be primarily agonistic. I observed itmainly when juveniles or other bird specieswere present in the display area. As in the dis-play described above, the male flies to his mainperch or another higher perch 15 to 20 m away,and then flies rapidly downward, ending with aninverted ‘‘U’’ trajectory toward his main perch.Upon arriving at the perch, he vocalizes (Fig.4g) or, less frequently, makes a buzzing noise(probably of mechanical origin, recordings arenot available). As in P. mentalis, this buzzingnoise is similar to the sound produced by jerkinga piece of cloth between the hands (Skutch1949, pers. obs.) but softer. In a few observa-tions of this behavior, the male remained frozenfor a few seconds after arriving on his displayperch and then made about-faces, wing-flicks 1pivots, and flight displays.

Frenzied-flutter. This display is a pseudo-cop-ulation, in which the male performs a brief flut-tering flight while hovering above the displayperch or a nearby leaf and emitting the frenzied-flutter call. This display occurred generally whenthe male was highly excited (e.g., when an un-receptive female left the display perch).

Advertisement call. The typical advertisementcall is a multisyllabic Fui-ii-ii-i—chi-awaaakthat lasts for about 1.7 sec (Fig. 4a). It is ho-mologous to calls described for P. cornuta, P.mentalis, P. rubrocapilla, and P. erythrocephala(Skutch 1949, Snow 1962, 1977, Sick 1967, Lill1976). Introductory (IP) and main (MP) phrasesare easily distinguished in the advertisementcall. The MP is preceded by the IP in 43% ofall advertisement calls. The IP never follows theMP and is rarely given alone. The IP consists ofthree to six short whistles that decrease in fre-quency from 4 to 2 kHz and last about 0.5 sec.The MP is the most frequently heard type ofadvertisement call at P. chloromeros leks (57%).This vocalization is a three-element call, chi-a-waaak, that lasts for about 0.3 sec. The MPstarts with a dominant frequency of about 7 kHz(first element), shifts downward to about 2 kHz(second element), and finishes with a buzzingsound (third element) at about 4 kHz. In general,advertisement calls are loud and can be heard upto 100 m away. These calls were rarely givenwhen a female was on the lek and were never


FIGURE 2. Sketches of some phases of the display dance of Pipra chloromeros. (a) The backward slide. (b)The U-posture at the end of the backward slide. (c), (d), and (e) The horizontal wing-spread performed at theend of the backward slide or during encounters at territory boundaries.

given by a male when a female was on his dis-play perch. Advertisement calls may function toattract females to the arena; however, they prob-ably also function intrasexually as territorial

calls analogous to oscine territorial songs (Lill1976, Robbins 1983).

Appeasement whistles. This less frequent vo-calization (4.3% of the total) is a sharp two-note

306 JOSE G. TELLO

FIGURE 3. Courtship behavior of Pipra chloromeros. Drawings show different phases of the copulatorybehavior of this species. (a) Type I flight display. (b) Squatting displays. (c) and (d) Copulations usually takeplace immediately after the male performs a backward slide toward the female. (e) After mating, male andfemale ‘‘freeze’’ for 15 to 30 sec.


FIGURE 4. Spectrograms of vocalizations and other sounds of Pipra chloromeros recorded in southeasternPeru. All spectrograms were made with wide band setting. (a) Advertisement call: introductory phrase (IP) andmain phrase (MP). (b) The appeasement whistle. (c) ‘‘Typical’’ display call. (d) and (e) Variations of the displaycall. (f) Type I flight display call. (g) Type II flight display call. (h) Frenzied-flutter call (5 copulation call). (i)Double-wing snap.

308 JOSE G. TELLO

call, fi-u, that lasts for about 0.1 sec (Fig. 4b).The first note is a short inverted-V whistlewhose dominant frequency decreases from 5 to2 kHz. This note is followed by a short unin-flected whistle of about 2 kHz dominant fre-quency (Fig. 4b). Appeasement calls appearedto convey a nonaggressive state of the caller.These calls were performed by a male immedi-ately after finishing a territorial encounter, or bya juvenile male after displaying with an adultterritorial male. The call may signal that a sub-ordinate wants to stop displaying with a domi-nant male. Vocalizations performed under simi-lar circumstances have been described for P. fas-ciicauda males by Robbins (1983).

Display calls. The typical display call is athree-note Fi-cuac-cuac that lasts about 0.6 sec(Fig. 4c). The first note is a short inverted-Vwhistle with a dominant frequency of about 4kHz. This whistle is followed by two buzzingnotes, each with a dominant frequency of about4 kHz. Variations of the call include a four-notecall formed by a series of short whistles that arefollowed by three buzzing notes with slightlylower dominant frequency (Fig. 4d), or threebuzzing notes followed by several whistles (Fig.4e). These vocalizations usually were given be-fore and during encounters among territorialmales, and following outbursts of display activ-ity at other courts within the lek, contexts similarto those described for these calls in P. fascii-cauda (Robbins 1983). Such calls are likely usedby territorial males to indicate their presence inthe display area.

Type I flight display call. This is a short, high-pitched call, Fu-fi-fu, that lasts for about 0.5 sec.The call starts at a frequency of 7 kHz (firstelement), slides down to 5 kHz (second ele-ment), and rises to 6 kHz (third element) at theend (Fig. 4f). This vocalization was always as-sociated with type I flight display.

Type II flight display call. This call is formedby a series of 6–7 short whistles that increase infrequency and intensity from 2 to 5 kHz, fol-lowed by a single buzzing note with a dominantfrequency of about 7 kHz that lasts about 0.3sec (Fig. 4g). This vocalization was always as-sociated with type-II flight display.

Frenzied-flutter call. This vocalization is atwo-note call, eeeee-eeeee that lasts about 1.8sec; the elements have a dominant frequency ofabout 5 kHz (Fig. 4h). This call was always as-sociated with the frenzied-flutter display and is

spectrographically similar to the call performedduring copulation.

Double-wing snap. The double snap consistsof two broad frequency pulses 0.03 sec apartwith a dominant frequency of about 5 kHz (Fig.4i). This sound is mechanically produced by thewings. Males performed this sound upon landingon the perch during the to-and-fro flight and usu-ally during the squatting display. This mechan-ical sound may accent the arrival of the display-ing male on the perch.

MALE SOCIAL STATUS AT LEKS

Observations of color-banded birds in previousmanakin studies indicated that males go througha progression in social status within a lek (Lill1976, Foster 1977, 1981). This also seems to bethe case for P. chloromeros. I distinguishedthree male social categories:

Territorial adult males. Males have the defin-itive plumage and spend most of the day andprobably most of the year on the lek. Thesemales display mainly on one perch, defending itand the court against neighbors, and they are thefirst to display to visiting females.

Non-territorial adult males. These males alsohave the definitive plumage and sporadicallyvisit territorial males. These males mainly re-stricted their activities to peripheral areas of thelek, where they vocalized, perhaps trying to es-tablish their own court. Non-territorial maleswere subordinate to territorial males, and terri-torial males always excluded them from theirterritories.

Immature males. These are non-territorialmales in non-definitive plumages. Immaturemales have been observed to molt from theirolive-green, female-like plumage after two re-productive periods (pers. obs.), as has been re-ported in other Pipra spp. (Lill 1976, Robbins1985; M. Foster, pers. comm.). Young maleswere generally tolerated by territorial males;they were primarily observers or performed in-complete, uncoordinated displays. Some pre-sumably older immatures performed completedisplays with the territorial males and behavedmore aggressively than other immature males.Occasionally, adults displayed to immaturemales as they did to adult females.

INTRASPECIFIC TERRITORIALITY

I plotted the locations of 122 boundary encoun-ters between territorial males at one lek (Fig. 5).


FIGURE 5. Territorial structure of lek 12 during the 1994 breeding season. Stippled areas represent the terri-tories of resident males at this lek. Capital letters represent the identities of territorial males. Open areas are theminimal convex polygons enclosing all encounter sites (open circles) of each pair of neighboring males. Thedotted and solid borders enclose the maximal estimated area of the lek. Pie diagrams show the proportions ofencounters between resident males and their closest neighbors.

Pipra chloromeros leks consist of mutually ex-clusive territories (or courts). As with other lek-king species, each male dominates all others onhis court, and generally excludes them from it(Lill 1974, 1976, Hoglund and Alatalo 1995).The three-dimensional courts appeared to be de-fended and maintained by ritualized agonisticencounters among territorial males; they rarelyended in fights. Encounters between pairs of ter-ritorial males took place close to the borders of

their courts on horizontal, 4.5–12 m high perch-es that constituted ‘‘neutral areas,’’ in which nei-ther male apparently had control (Fig. 5). Neu-tral perches were generally located in placesprotected both above and on the sides by vege-tation (e.g., entangled vines or clusters of deadleaves). Territorial encounters usually occurredduring the morning (Fig. 6a). Before interactionstook place, territorial males generally counter-sang from perches located between their courts.

310 JOSE G. TELLO

FIGURE 6. (a) Timing of daily territorial encountersat territory boundaries from two leks of Pipra chlo-romeros from Cocha Cashu. (b) Percentage of timeterritorial males were absent from their courts for eachperiod of observation. (c) Calling and display activityat Pipra chloromeros leks. Black squares represent theproportion of time males spent vocalizing during eachperiod of observation. White squares represent the pro-portion of type I flight displays performed by territorialmales during each period of observation.

The display call, Fi-cuac-cuac, was repeatedseveral times before and during the encounters.Neighboring males rarely engaged in fights oractive displays, suggesting that they recognizeeach other. During encounter displays, males en-gaged simultaneously in wing-spreading andquivering (Fig. 7a), which they alternated withbackward slides, side-to-side slides, about-faces,and wing-flicks 1 pivots. Wing-spreading wasgenerally accompanied by simultaneous displaycalls (Fi-cuac-cuac, or cuac-cuac). Backward

sliding typically involved the approach of onemale to the other, and generally ended in theother male withdrawing (Fig. 7b). During en-counters, males sometimes rested close to eachother for several minutes (Fig. 7c), immediatelyafter which they displayed again. Encountersended when one of the males abandoned thearea, flying toward its court. Encounters betweenneighbors involved slow, coordinated displaysand were similar to displays performed towardfemales or intruding males.

Four of seven pairs interacted often enough toanalyze dominance relationships, but significantdifferences existed for only two interacting pairs(YD-BR and YD-DG, Fig. 5). YD never with-drew in interactions with BR (Mann-Whitney U-test, U 5 18, P , 0.05) or DG (Mann-WhitneyU-test, U 5 12, P , 0.05). In contrast, WB fre-quently approached OR but was not obviouslydominant based on the low number of OR with-drawals (Mann-Whitney U-test, U 5 44, P .0.05). These findings suggest that some degreeof dominance may exist. Further, dominance re-lationships may change over time (Robbins1985). I rarely saw widely separated males in-teract at lek 12 (i.e., males WB and YD in Fig.5). At lek 10, where territorial males rarely in-teracted, intermale distance averaged about fourtimes greater than at lek 12.

On three occasions, I observed more complex,coordinated flight displays at the main perchesof three males. The interactions involved a ter-ritorial male and an adult or immature male vis-itor, but never two territorial males. The two dis-playing birds alternated a series of stereotypeddisplays that included (in order of occurrence):upright postures, wing-flicks 1 pivots, displaycalls, squats, type I flight displays and associatedcalls, backward slides, and the U-posture (Fig.8). The displays started with the two males hold-ing the upright posture for a few seconds, im-mediately after which ‘‘male 1’’ performed a se-ries of wing-flicks 1 pivots before flying to an-other perch ca. 7 m away from the display perch.He then uttered a type I display call, and gavea type I flight display and flew back to the orig-inal perch (Fig. 8a). At the same time, ‘‘male2,’’ which was giving the display call, per-formed an about-face and several squatting dis-plays, moving away from the center of the dis-play perch (Fig. 8b). When male 1 landed on theperch, both males performed simultaneous back-ward slides toward each other (Fig. 8c, d). This


FIGURE 7. Coordinated ritual display at territory boundaries. (a) Neighboring males display together andperform a display call. (b) One male approaches the other using a backward slide, which occasionally causesthe other male to withdraw. (c) During the encounters, resident males rest close to each other for some minutesuntil they start to display again.

was followed by the U-posture held until bothmales depressed their tails, which appeared totouch each other (Fig. 8e). They gave this dis-play (backward slide 1 U-posture) twice. Then,one of the birds uttered a display call to whichthe other male responded. Suddenly, male 2 flew

away from the display perch and repeated thesame coordinated flight display. The two malesalternated, performing a total of 26 (13 each) ofthese coordinated flight displays for almost 5min. Sometimes, the bird that remained on thedisplay perch performed a series of to-and-fro

312 JOSE G. TELLO

FIGURE 8. Coordinated flight displays at one male’s territory. (a) After flying away from the main perch, oneof the males returned with a type I flight display, uttering a type I flight display call upon landing. (b) At the sametime, the second male, which was giving the display call, performed several squatting displays. (c) and (d) Whenthe former bird landed on the perch, both males performed simultaneous backward slides toward each other. Thiswas followed by the (e) U-posture held until both males depressed their tails, which appeared to touch each other.Then, both birds uttered display calls, until the latter bird flew away and re-initiated the displays.


flights, followed by squatting displays, beforethe other male landed on the main perch. Afterresting for two minutes while maintaining theupright posture, the males reinitiated the display,but this time they performed only six (threeeach) coordinated flight displays. The displaysended when male 2 abandoned the perch. Inter-actions involving coordinated flight displayshave been observed to occur under similar cir-cumstances in P. fasciicauda (Robbins 1983)and P. mentalis (pers. obs.).

INTERSPECIFIC TERRITORIALITY

Pipra chloromeros males showed a certain de-gree of interspecific territoriality around theirdisplay areas. I observed territorial males chas-ing males of two other manakin species, P. co-ronata and P. fasciicauda, when they ap-proached their display areas. Other birds, suchas the White-winged Shrike-Tanager (Lanio ver-sicolor), Orange-bellied Euphonia (Euphoniaxanthogaster), and Dusky-throated Antshrike(Thamnomanes ardesiacus) were also excluded.Territorial males usually displayed actively ontheir display perches when a mixed-species flockmoved through their courts, but males did notchase flock species. Occasional presence of fe-males or young males of P. chloromeros in theseflocks also caused males to display.

SEXUAL BEHAVIOR

Pipra chloromeros breeds mainly from earlyAugust to the end of November. Female visitswere recorded mostly during midday (10:00–14:30). Most visits (n 5 9) were by a singlefemale, but once I recorded two females visitinga single male at the same time. Lill (1976) re-corded some P. erythrocephala females visitingmales in pairs, and Foster (1977) also reportedpairs of females visiting a single Chiroxiphia li-nearis male.

Territory attendance. Males were present ontheir territories from 58% to 85% of the obser-vation time (mean 5 73.3 6 3.3%). The pro-portion of time that males were absent from theirterritories varied significantly among observa-tion periods (ANOVA: F4,92 5 5.2, P , 0.001),being greater during late afternoon (14:30–16:00; mean 5 50.2% of male absenteeism) thanat any other time (Fig. 6b). During hours whenmost females were recorded visiting the lek(10:00–14:30), males were absent from theirdisplay areas only 20% of the time. During those

hours, feeding bouts were short and directedmainly to fruiting trees or shrubs within themale’s territory. In the early morning (06:00–07:00) and late afternoon (after 15:00), malesspent significantly more time (mean 5 4.8 minper feeding bout) feeding in fruiting trees thanthey did during the middle of the day (mean 51.3 min per feeding bout; U 5 67.5, P , 0.01).

Courtship behavior. Calling activity at theleks (based on number of advertisement calls)was most intense from 12:00 to 14:30 (Fig. 6c;ANOVA: F4,104 5 6.5, P , 0.001). Display ac-tivity (based on number of type I flight displays)also varied significantly during the day (Krus-kal-Wallis, x2

4 5 12.0, P , 0.05); activity wasconcentrated between 10:00 and 14:30 (Fig. 6c).

As expected, hours when female visitationwas highest (10:00–14:30) coincided with out-bursts of display activity within the leks. Unfor-tunately, because the cryptically colored femalesare difficult to detect unless they move, it wasnot always possible to tell if the arrival of a fe-male stimulated males to display or the outburstsof male display attracted the females. The lackof significant differences in display activity(based on frequency of flight displays) betweenthe successful males (those which obtained allthe observed copulations) and other territorialmales at one lek (Kruskal-Wallis, x2

4 5 3.2, P. 0.05) suggests that the outburst of male dis-play activity may be a response to a female vis-iting the lek. The small number of observed cop-ulations makes it difficult to generalize, how-ever. Apparently, males at a lek have a mutuallystimulating effect, so that when one starts to dis-play a general increase in activity results (Snow1962, Lill 1976).

Copulatory behavior. The five observed cop-ulations took place between 13:00 and 14:30.Copulations followed displays on the main perchincluding all or several of the following displayelements: type I flight displays, backward slides,about-faces, to-and-fro flights, squats, wing-flicks, pivots, and the upright posture (Fig. 3a–c). In contrast to Lill’s (1976) observations of P.erythrocephala females (which might have beenimmature males) participating with males in thecourtship displays, I only saw P. chloromerosfemales in an upright posture (Fig. 3b, c, e). Fe-males sometimes delivered very light pecks tothe male’s head feathers as he approached her.This behavior is also known for P. erythrocep-hala (Lill 1976) and the Guianan Cock-of-the-

314 JOSE G. TELLO

TABLE 3. Number of visits by females and immatures, copulations, advertisement calls, flight displays, andagonistic encounters at two Pipra chloromeros leks of different size. * P # 0.05, Mann-Whitney U-test.

Sexual attraction anddisplay level measures

Total

Lek 12a Lek 10a

Average per male

Lek 12 Lek 10

Visits by femalesVisits by immaturesObserved copulationsAdvertisement callsFlight displaysAgonistic encounters

7*93

1473*103*122*

060

608258

1.41.80.6

294.620.624.4*

03.00

304.012.5

4.0

a Lek 12 5 5 males; Lek 10 5 2 males.

Rock (Rupicola rupicola, Snow 1971). Copula-tions were immediately preceded by (1) Type Iflight displays in which the male landed besidethe female on the display perch and then jumpedonto her back (n 5 2); (2) backward slides, fol-lowing which the male jumped onto and coveredthe female (n 5 2); or (3) a squatting display (n5 1).

Copulations lasted 2 to 4 sec, during whichthe male beat his wings and emitted two buzzingnotes (Fig. 3d). Immediately after mating, thepair froze for about 15 to 30 sec (one pair frozefor nearly 100 sec), with the male maintaining ahorizontal posture (parallel to the perch) and thefemale maintaining the upright posture (Fig. 3e).During this time, females were observed to con-tract the cloacal opening. Freezing and cloacalclosure may help the female to retain sperm. Themale then began to perform a series of squatting,backward slide, wing-flick, pivot, flight display,and to-and-fro flight displays, perhaps trying tocopulate again with the same female. One malecopulated twice in 15 min, but I could not de-termine if the same female was involved. Aftera female departed, males usually continued dis-playing vigorously for a few minutes, and theneither resumed advertising or abandoned thecourt.

Measures of sexual attraction, calling activity,and display activity differed somewhat betweentwo P. chloromeros leks, one with two malesand the other with five (Table 3). Female visi-tation and copulations were seen only at thelarger lek, where two males received all the ob-served visits (n 5 7) during the focal samples.In contrast, total number of visits by immaturesdid not differ between leks. Overall calling anddisplay activity were greater at the larger lek but,on average, individual males at this lek did notcall or display more than did males at the small-

er lek (Table 3). Encounters among territorialmales were more frequent at the larger lek, andindividual males from the larger lek were in-volved in significantly more territorial encoun-ters than those from the smaller lek.

DISCUSSIONLEK ORGANIZATION

Based on numbers of males (two to five) and thediameters of their territories (.20 m), leks of P.chloromeros are more similar to those of P. cor-nuta (Snow 1977) and P. rubrocapilla (pers.obs.) than to those of P. mentalis (Skutch 1949,1969; pers. obs.) and P. erythrocephala (Snow1962, Lill 1976). Using Prum’s classification oflek spatial organization (1994), the leks of theformer three species fall into the category of dis-persed leks, whereas Pipra mentalis and P.erythrocephala have concentrated leks (Table 1in Prum 1994).

INTRASPECIFIC TERRITORIALITY

In general, the nature of interactions among ter-ritorial males of P. chloromeros was similar tothose among male P. erythrocephala (Lill 1976).However, the behaviors of these two speciescontrast with descriptions of male-male interac-tions in other manakins such as Manacus ma-nacus (Lill 1974) or P. coronata (M. Foster,pers. comm., pers. obs.) in which the outcomesof male boundary encounters were more easilydetermined.

The nature of these encounters suggests thatcourt boundaries constitute ‘‘neutral zones,’’ in-stead of finite lines, in which no male complete-ly dominates neighboring males (Lill 1974,1976). Such coordinated displays between malesoccur in other manakins of the same clade (e.g.,in P. erythrocephala, Lill 1976, Snow 1962; inP. rubrocapilla, Sick 1959a, 1967; in P. men-


talis, Skutch 1949, 1969). Encounters at territoryboundaries have been suggested to function inestablishing and maintaining dominance rela-tionships among males (Foster 1981, Bradburyand Davies 1987). Observations of female-plumaged birds interacting as adults on perchesfar from any known lek (pers. obs.) indicate thatthese interactions start early in the male’s life.

EFFECT OF LEK SIZE ON FEMALEATTRACTION AND OVERALL MALEBEHAVIOR

Variation in lek size within a study populationhas been recorded for several lekking species(Hoglund and Alatalo 1995). This variation maybe influenced by various factors, including: (1)the number of females using a patch of habitatnear the lek (Bradbury and Gibson 1983); (2)the quality of the alpha male(s), that may causeother, less successful males to cluster aroundthose ‘‘hotshots’’ (Beehler and Foster 1988); and(3) the structure of the habitat in which the leksare located (Olson and McDowell 1983). Withina population, smaller leks may be short-lived,eventually driven to extinction as a result of fe-male preferences for larger clusters of males(Bradbury 1981, Beehler and Foster 1988). Dis-play levels in large leks are expected to be moreintense than those in small leks due to socialfacilitation (closer male territories; Lack 1939,1946). The high level of display and calling ac-tivity at large leks probably exert disproportion-ately attractive and stimulative effects on fe-males (Alatalo et al. 1991). If so, then malesdisplaying in larger groups should have a highermean reproductive success than males in smallergroups.

The lekking behavior of P. chloromeros re-ported here leads to some interesting observa-tions, even given sample size limitations: (1) Itis unlikely that differences in female abundanceexplain the observed differences in lek size, be-cause the leks were only approximately 670 mapart. The observed distance between leks fallswithin the female home-range size estimated forother Pipra species (Thery 1992), and manakinfemales can include more than one lek in theirhome ranges (Thery 1992; M. Foster, pers.comm.). Thus, it is possible that both leks couldhave been visited by the same females. (2) Con-trary to expectation, (following Bradbury 1981and Beehler and Foster 1988), both leks main-tained the same number of males during 7 years.

(3) Overall activity was greater at the larger lek,but the numbers of vocalizations and displaysthat each male performed did not differ signifi-cantly. Thus, males at the smaller lek did notnecessarily call or display more to compensatefor their lower numbers, and so increase their‘‘radius of attractiveness’’ (Bradbury 1981). (4)Males at the larger lek were surrounded by moreneighbors and so might be expected to expendmore time in territorial encounters than males atthe smaller lek (Lill 1976, Beehler and Foster1988). This was confirmed by the higher overallnumber of territorial encounters recorded at thelarger lek (n 5 122) compared with that record-ed at the smaller one (n 5 8). Individually,males from the larger lek were involved in moretotal interactions (mean 5 24.4 6 5.8) thanthose from the smaller one (mean 5 4.0 6 0.6).Finally, (5) the fact that females visited only twoof five males at the larger lek suggests that non-alpha males would not gain much from cluster-ing, at least in the short term. Lill’s (1976) stud-ies of leks of P. erythrocephala showed similarresults; males at smaller leks were not at a se-lective disadvantage, and on average had sexualsuccess similar to those of males at larger leks,supporting the hypothesis that lek size is deter-mined by the effect of particularly successfulmales (Beehler and Foster 1988, Alatalo et al.1991). However, other factors, such as vegeta-tion structure at the lek could also constrain thenumber of males at one site. More studies onhabitat characteristics of lek sites, as well aslong-term studies of mating success and tenureof alpha males, are required to fully answerquestions related to lek formation and mainte-nance.

EVOLUTIONARY IMPLICATIONS OF PIPRACHLOROMEROS DISPLAYS

The genus Pipra is divided into two clades: theP. erythrocephala clade (cornuta, mentalis,erythrocephala, chloromeros, and rubrocapilla)and the P. aureola clade (aureola, fasciicauda,and filicauda) (Prum 1992). Vocalizations anddisplays are remarkably similar between P. chlo-romeros and other members of the P. erythro-cephala clade (Table 4). In his study on the evo-lution of manakin displays, Prum (1990) recog-nized 11 different displays for the P. erythro-cephala clade. Four of those displays (horizontalposture, frenzied-flutter, to-and-fro flight, andtype I flight display) are present primarily in the

316 JOSE G. TELLO

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genus Pipra; five (upright posture, about-face,backward slide, double-wing snaps with to-and-fro-flight, and the buzzing noise with type IIflight) are found only in the P. erythrocephalaclade and are probably derived; and two consti-tute displays that prior to this study were foundonly in the repertoire of P. cornuta (side-to-sideslide and backward slide with forward rebound;Table 4). Because, at the time of Prum’s work,the lekking behavior of P. chloromeros waspoorly known, I decided to compare the behav-iors of the species in this clade in more detailbased on reanalysis of the literature on displays(Table 4). Although observations for P. cornutaare still incomplete (Snow 1977), some interest-ing trends are apparent among these five species.

Type I flight display is derived in Pipra (Prum1990), and usually includes a high-pitched shortcall given by the male upon landing (present inP. fasciicauda), which may have evolved si-multaneously with the flight display (assumingthat the call is present in P. cornuta). The callis absent from P. mentalis and P. erythroceph-ala, and is unknown in P. rubrocapilla. Type IIflight display (catapult-like flight) probably con-stitutes a variation of type I flight display that isderived in the P. erythrocephala clade. As intype I, the bird vocalizes when it lands. The vo-calization consists of a single or multiple notecall (Fig. 4g) that always ends with a buzzingnote given as the bird arrives at the displayperch. In general, the structures of associatedcalls as well as the context in which flight dis-plays are performed differ among species withinthe P. erythrocephala clade. Type I flight dis-play is used mainly during courtship by P. chlo-romeros, which performs type II mostly duringinteractions with non-territorial males. In con-trast, P. mentalis and P. erythrocephala use typeII displays mainly during female courtship (Lill1976, pers. obs). Thus, between P. mentalis andP. erythrocephala, the primary function of typeII flight display has changed.

Structural modifications of secondary feathershave allowed the production of mechanicalsounds in manakins (Sick 1967, Prum 1998). InPipra spp., several displays have evolved to in-corporate mechanical noises, perhaps in order toincrease the conspicuousness of the display andto attract the attention of the visiting bird towardthe main display area. Mechanical noises havebeen recorded in three (P. cornuta, P. mentalis,and P. chloromeros) of the five members of the

318 JOSE G. TELLO

P. erythrocephala clade. As expected, the twospecies from which mechanical noises are absent(P. rubrocapilla and P. erythrocephala) alsolack the associated modifications of the second-ary wing feathers (Prum 1998). Displays inwhich mechanical noises are found include to-and-fro flight, squatting display, type II flightdisplay, and the stereotyped wing-snapping twistdisplay (only described for P. mentalis).

Mechanical noises associated with the to-and-fro flight are controlled wing snaps performedwhile flying (P. cornuta, P. mentalis), or im-mediately after landing (P. cornuta, P. mentalis,P. chloromeros). Mechanical wing noises asso-ciated with the squatting display are present inP. chloromeros and P. mentalis (pers. obs.), andare unknown in P. cornuta. Sometimes, birdsmake a whirring mechanical noise upon landingafter a type II flight display (the mechanical-noise flight, Prum 1990). These noises are madeby P. mentalis and P. chloromeros but are un-known in P. cornuta.

One of the more unusual behaviors describedin the P. erythrocephala clade is the wing-snap-ping twist display of P. mentalis (Skutch 1949,1969). This display may have evolved from theabout-face movement (a trait found primarily inPipra) and wing-flicking (a common display inPipridae and other Tyrannoidea). Males of P. ru-brocapilla also include snapping sounds in theirdisplay repertoires (Library of Natural Sounds32030), but because the secondary feathers arenot modified, these sounds presumably have avocal instead of a mechanical origin (Sick1967). These sounds are associated with about-faces and wing-flicks as they are in P. mentalis(Sick 1967).

The upright posture is a derived display in theP. erythrocephala clade (Prum 1990) that is per-formed by all the members of the group withoutapparent modifications. The orientation of a male’sposterior toward a visitor is also widespread inPipra (Sick 1967, Robbins 1983, Prum 1990).This behavior can be found in the tail-up freezeof P. fasciicauda (Robbins 1983) and the back-ward slide of the P. erythrocephala clade (Prum1990).

The backward slide and side-to-side slide areelaborate displays that apparently evolved fromthe horizontal posture (primitively present in thegenus Pipra, Prum 1990). Prum (1990) suggest-ed that the backward slide and side-to-side slidedisplays are derived in the P. erythrocephala

clade. However, similar displays have been re-corded for the P. aureola clade (Snow 1963b,Schwartz and Snow 1978, Robbins 1983), whichmay place the evolution of these displays withan ancestor of these two clades. Snow (1963b)described the side-to-side and backward-and-forward displays of P. aureola as movements inwhich the bird literally slides on the perch. Al-though Schwartz and Snow (1978) described theside-to-side diplay of P. filicauda as a movementin which the bird jumps very rapidly to one sideon the perch, they also noted the similarity ofbackward jumps of this species to the slidingdisplays observed in other Pipra. In the sameway, Robbins (1983) described the side-to-sidedisplay of P. fasciicauda as jumps or hops toone side of the perch, but he also pointed outthat from the tail-up freeze position (a modifi-cation of the horizontal position), the male mayback toward the visiting bird while performingthis display. This strongly suggests that back-ward slides and side-to-side slides arose in theancestor of Pipra, and were then modified toinclude jumps (side-to-side), or to largely dis-appear (backward slide only) in the repertoiresof P. filicauda and P. fasciicauda. This also sug-gests that P. filicauda and P. fasciicauda mightbe sister species, which would explain the pres-ence of jumps in the side-to-side display of thesetwo species.

The side-to-side slide is apparently absentfrom P. erythrocephala, and is unknown in P.rubrocapilla. Most of the members of the P.erythrocephala clade (Prum 1990) usually endthe backward slide with a horizontal wing-spreading and fanning of the lowered tail. Pipramentalis and P. erythrocephala, in contrast,raise their wings vertically above the back andsimultaneously lower and fan the tail. In thisgroup, the backward slide serves as the base foraddition of terminal movements and postures,such as the tail-shivering of P. mentalis (Skutch1949, 1969), U-posture of P. chloromeros, andforward rebound of P. cornuta (Snow 1977).Other variations of the backward slide include:(1) tail slightly depressed and wings slightlyraised during sliding (P. cornuta and P. rubro-capilla); (2) wings held above the back duringthe slide (P. mentalis; Skutch 1949, 1969); and(3) rapid opening and closing of wings halfwaydown the slide (P. erythrocephala, Table 4).

Within the P. erythrocephala clade, differenc-es in visual stimulation (display movement and


thigh coloration) exhibited to females during thebackward slide may constitute important isolat-ing mechanisms. Displays in which males orienttheir posteriors toward a female or other visitorhave been suggested as one of the factors pro-moting the evolution of striking plumage pat-terns in some manakins (Robbins 1983). Duringthe backward slide, males of the P. erythroceph-ala clade straighten their legs to show theirfeathered thighs (bright yellow, white-red, orred). Backward slides and colored thighs areboth derived characters in this group. Thus, itseems that both characters arose at the sametime without any apparent influence on one an-other. Another example of simultaneous originof behavioral and plumage characters is foundin the wing-raising display of P. rubrocapilla,and the wing-snapping twist display of P. men-talis. These postures would serve as a visualstimulus to the female during courtship, byshowing the conspicuous white and yellow un-derwing spots. These postures have not been re-corded in the other three species, which lack un-derwing color spots.

Advertisement calls in the P. erythrocephalaclade share features that make them differentfrom calls of the members of the P. aureolaclade. In the P. erythrocephala clade, advertise-ment calls are composed of several elements(e.g., different types of whistles, buzzing notes,and trills), whereas in the P. aureola clade, ad-vertisement calls are composed of a singledownwardly inflected whistle (Snow 1963b,Schwartz and Snow 1978, Robbins 1983). In theP. erythrocephala clade, an introductory and amain phrase are usually distinguished in the ad-vertisement call (Skutch 1949, Snow 1962, Sick1967, Lill 1976). The frenzied-flutter call isfound only in the P. erythrocephala clade; in theP. aureola clade the display is silent (Schwartzand Snow 1978, Robbins 1983). Other vocali-zations, such as display calls and appeasementwhistles, are also found in some members of theP. aureola clade (Robbins 1983).

Male-coordinated displays (both the ritual dis-play and the active flight display) in the P. eryth-rocephala clade seem to be more important fordominance relationships than for mate attraction.This is supported by the observation that bothritualized and actively coordinated displays areperformed by males in the absence of females.The lack of more aggressive displays among ter-ritorial males in the P. erythrocephala clade

probably is a consequence of greater intermaledistances (Foster 1983). In P. chloromeros, Inever observed a territorial male visit the maindisplay perch of another territorial male. Ritualdisplays may reflect previous aggressive inter-actions among neighboring males.

Eighteen of the 34 display elements presentin the P. erythrocephala clade have also beenrecorded in the P. aureola clade. The remaining16 display elements are present only in the P.erythrocephala clade, and seven of those ele-ments constitute behavioral autapomorphies of aparticular species. Not surprisingly, all displaynovelties were associated with displays particu-larly important during female courtship (e.g., thebackward slide, Table 4). The great diversity ofdisplays observed in the P. erythrocephala cladecould have arisen under intense sexual selection(particularly intense in polygynous systems) act-ing on displays important for mate selection(Lande 1981, West-Eberhard 1983, Prum 1997).At some point following geographic isolation,behavioral differences among closely relatedforms would probably be enough to preventmating and cause reproductive isolation.

ACKNOWLEDGMENTS

I thank M. Foster, who introduced me to the study ofmanakin behavior in 1987. She also provided unpub-lished data used for vegetation analyses in this study.John Terborgh supported me logistically and finan-cially during several field seasons at Cocha Cashu. TheInstituto Nacional Forestal y de Fauna (INRENA) pro-vided permits to work in Manu National Park. Thisstudy was supported by a F. M. Chapman Grant fromthe American Museum of Natural History, the ConsejoNacional de Ciencıa y Tecnologıa del Peru, WorldWildlife Fund (through J. Terborgh), the InternationalCenter for Tropical Ecology, and the Graduate Schoolof the University of Missouri-St. Louis (UMSL). Fieldwork was aided by L. Lopez, L. Morton, H. Zeballos,O. Hernandez, and D. Neyra. R. Flores, J. Quispe, M.Sanchez, M. de Sanchez, as well as the Machiguengapeople made my time at Cocha Cashu very enjoyable.R. Ranft and P. Duck from the British Library of Wild-life Sounds, G. Budney from the Cornell Library ofNatural Sounds, and R. Prum made available record-ings of Pipra spp. Behavioral illustrations were pre-pared by M. Skakuj. P. and M. Isler helped with advicefor preparing sonograms. The manuscript was greatlyimproved by comments from M. Foster, J. Bates, J.Blake, B. Loiselle, G. Bourne, R. Prum, M. Ashley,and members of Blake’s lab. J. Blake, B. Loiselle, J.Perez, S. Brugada, and E. Joern supplied support andhospitality during my years at UMSL.

320 JOSE G. TELLO

LITERATURE CITED

ALEXANDER, R. D. 1974. The evolution of social be-havior. Annual Review of Ecology and System-atics 5:325–383.

ALTMANN, J. 1974. Observational study of behavior:sampling methods. Behavior 49:227–265.

ALATALO, R. V., J. HOGLUND, AND W. J. SUTHERLAND.1991. Evolution of black grouse leks: female pref-erences benefit males in larger leks. BehavioralEcology 3:53–59.

BEEHLER, B., AND M. S. FOSTER. 1988. Hotshots, hot-spots, and female preference in the organizationof lek mating systems. American Naturalist 131:203–219.

BRADBURY, J. W. 1981. The evolution of leks, p. 138–169. In R. D. Alexander and A. D. W. Tinkle[EDS.], Natural selection and social behavior. Chi-ron Press, New York.

BRADBURY, J. W., AND N. B. DAVIES. 1987. Relativeroles of intra- and intersexual selection, p. 143–163. In J. W. Bradbury and M. B. Anderson [EDS.],Sexual selection: testing the alternatives. John Wi-ley & Sons, Chichester, UK.

BRADBURY, J. W., AND R. M. GIBSON. 1983. Leks andmate choice, p. 109–138. In P. Bateson [ED.], Matechoice. Cambridge University Press, Cambridge,UK.

CHAPMAN, F. M. 1929. My tropical air castle: naturestudies in Panama. D. Appleton and Company,New York.

CHARIF, R. A., S. MITCHELL, AND C. W. CLARK. 1995.Canary 1.2 user’s manual. Cornell Laboratory ofOrnithology, Ithaca, NY.

CRANDALL, L. S. 1945. A brilliant flash—that’s the ma-nakin’s display. Animal Kingdom 48:67–69.

FOSTER, M. S. 1977. Odd couples in manakins: a studyof social organization and cooperative breeding inChiroxiphia linearis. American Naturalist 111:845–853.

FOSTER, M. S. 1981. Cooperative behavior and socialorganization of the Swallow-tailed Manakin (Chi-roxiphia caudata). Behavioral Ecology and Socio-biology 9:167–177.

FOSTER, M. S. 1983. Disruption, dispersion, and dom-inance in lek-breeding birds. American Naturalist122:53–72.

FOSTER, R., J. ARCE, AND T. S. WACHTER. 1986. Dis-persal and sequential plant communities in Ama-zonian Peru flood plain, p. 357–370. In A. Estradaand T. H. Fleming [EDS.], Frugivores and seed dis-persal. Dr. W. Junk Publishers, Dordrechht, TheNetherlands.

GENTRY, A. H., AND J. TERBORGH. 1990. Compositionand dynamics of the Cocha Cashu ‘‘mature’’ floodplain forest, p. 542–564. In A. H. Gentry [ED.],Four Neotropical rainforests. Yale UniversityPress, New Haven, CT.

HAFFER, J. 1970. Art-Entstehung bei einigen Waldvo-geln Amazoniens. Journal fur Ornithologie 111:285–331.

HARVEY, M. J., AND R. W. BARBOUR. 1965. Homerange of Microtis ochrogaster as determined by amodified minimum area method. Journal of Mam-malogy 46:398–402.

HOGLUND, J., AND R. V. ALATALO. 1995. Leks. Prince-ton University Press, Princeton, NJ.

JAMES, F. C., AND H. H. SHUGART JR. 1970. A quanti-tative method of habitat description. AudubonField Notes 24:727–736.

JANDEL SCIENTIFIC. 1993. SigmaScan/Image. JandelScientific, San Rafael, CA.

KENDEIGH, S. C. 1944. Measurement of bird popula-tions. Ecological Monographs 14:67–106.

LACK, D. 1939. The display of the Black Cock. BritishBirds 32:290–303.

LACK, D. 1946. Black Cock display. British Birds 39:287–288.

LANDE, R. 1981. Models of speciation by sexual se-lection on polygenic traits. Proceedings of the Na-tional Academy of Sciences 78:3721–3725.

LILL, A. 1970. Dazzling display: courtship assembliesof the manakins. Animal Kingdom 73(5):24–29.

LILL, A. 1974. Sexual behavior in the lek-formingWhite-bearded Manakin, Manacus manacus tri-nitatis Hartert. Zeitschrift fur Tierpsychologie 36:1–36.

LILL, A. 1976. Lek behavior in the Golden-headedManakin, Pipra erythrocephala in Trinidad (WestIndies). Supple.18, Zeitschrift fur Tierpsycholo-gie.

MACDONALD, D. B. 1990. Correlates of male matingsuccess in a lekking bird with male-male cooper-ation. Animal Behaviour 37:1007–1022.

NIETHAMMER, G. 1956. Zur vogelwelt Boliviens (TeilII: Passeres). Bonner Zoologische Beitrage 7:84–150.

OLSON, D. H., AND M. K. MCDOWELL. 1983. A com-parison of White-bearded Manakin (Manacus ma-nacus) populations of lek systems in Surinameand Trinidad. Auk 100:739–742.

PRUM, R. O. 1990. Phylogenetical analysis of the evo-lution of display behavior in the Neotropical man-akins (Aves: Pipridae). Ethology 84:202–231.

PRUM, R. O. 1992. Syringeal morphology, phylogeny,and evolution of the Neotropical manakins (Aves:Pipridae). American Museum Novitates 3043.

PRUM, R. O. 1994. Phylogenetic analysis of the evo-lution of alternative social behavior in the mana-kins (Aves: Pipridae). Evolution 48:1657–1675.

PRUM, R. O. 1996. Display behavior and natural his-tory of the Yellow-crowned Manakin (Heterocer-cus flavivertex: Pipridae). Condor 98:722–735.

PRUM, R. O. 1997. Phylogenetic tests of alternativeintersexual selection mechanisms: trait macroevo-lution in a polygynous clade (Aves: Pipridae).American Naturalist 149:668–692.

PRUM, R. O. 1998. Sexual selection and the evolutionof mechanical sound production in manakins(Aves: Pipridae). Animal Behaviour 55:977–994.

RIDGELY, R. S., AND G. TUDOR. 1994. The birds ofSouth America: the suboscine passerines. Univer-sity of Texas Press, Austin, TX.

ROBBINS, M. B. 1983. The display repertoire of theBand-tailed Manakin (Pipra fasciicauda). WilsonBulletin 95:321–504.

ROBBINS, M. B. 1985. Social organization of the Band-tailed Manakin (Pipra fasciicauda). Condor 87:449–456.


SCHWARTZ, P., AND D. W. SNOW. 1978. Display andrelated behavior of the Wire-tailed Manakin. Liv-ing Bird 17:51–78.

SICK, H. 1959a. Die balz der schmuckvogel (Pipridae).Journal fur Ornithologie 100:269–302.

SICK, H. 1959b. Estudo comparativo das ceremoniaspre-nupciais de piprideos Brasileiros. Boletim doMuseu Nacional 213:1–17.

SICK, H. 1967. Courtship behavior in the manakins (Pi-pridae): a review. Living Bird 6:5–22.

SICK, H. 1993. Birds of Brazil. Princeton UniversityPress, Princeton, NJ.

SKUTCH, A. F. 1949. Life history of the Yellow-thighedManakin. Auk 66:1–24.

SKUTCH, A. F. 1969. Life histories of Central Americanbirds III. Cooper Ornithological Society, Berkeley,CA.

SNOW, D. W. 1956. Courtship ritual: the dance of themanakins. Animal Kingdom 59:86–91.

SNOW, D. W. 1962. A field study of the Golden-headedManakin, Pipra erythrocephala, in Trinidad, W.I.Zoologica 47:183–198.

SNOW, D. W. 1963a. The evolution of manakins dis-plays. Proceedings of the International Ornitho-logical Congress 13:553–561.

SNOW, D. W. 1963b. The display of the Orange-headedManakin. Condor 65:44–48.

SNOW, D. W. 1971. Notes on the biology of theCock-of-the-Rock (Rupicola rupicola). Journalfur Ornithologie 112:323–333.

SNOW, D. W. 1977. The display of the Scarlet-hornedManakin, Pipra cornuta. Bulletin of the BritishOrnithologists’ Club 97:23–27.

SNOW, D. W. 1979. Family Pipridae, p. 245–280. InM. A. Traylor Jr. [ED.], Check-list of birds of theworld. Museum of Comparative Zoology, HarvardUniversity Press, Cambridge, MA.

TELLO, J. G. 1996. Lekking behavior of the Round-tailed Manakin (Pipra chloromeros) and patternsof advertisement call evolution in the Pipra eryth-rocephala clade. M.Sc. thesis, University of Mis-souri-St. Louis, MO.

TERBORGH, J. 1983. Five new world primates. Prince-ton University Press, Princeton, NJ.

TERBORGH, J., S. ROBINSON, T. PARKER III, C. MUNN,AND N. PIERPONT. 1990. Structure and organiza-tion of an Amazonian forest bird community. Eco-logical Monographs 60:213–238.

THERY, M. 1992. The evolution of leks through femalechoice: differential clustering and space utilizationin six sympatric manakins. Behavioral Ecologyand Sociobiology 30:227–237.

WEST-EBERHARD, M. J. 1983. Sexual selection, socialcompetition, and speciation. Quarterly Review ofBiology 52:155–183.

LEKKING BEHAVIOR OF THE ROUND-TAILED MANAKIN

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