SPECIAL ISSUE PAPER

The Diverse Origins of Bird Bones fromScottish Coastal SitesD. SERJEANTSON*University of Southampton, Archaeology, Avenue Campus School of Humanities, Southampton, Hampshire,United Kingdom

ABSTRACT Bird bone assemblages from coastal sites in the north and west of Scotland are very diverse. Here, bird bonesfrom 25 assemblages from 15 sites are compared. Many birds were caught for food, but there are also up to50 incidental species, some of which are represented by one or two bones only. While the principal origin ofthe birds is seabird fowling, some were also obtained as a bycatch of fishing and others were collected casually.Some may have been collected accidentally with seaweed. Many are non-anthropogenic, from raptor discardsand bird pellets, but possibly also from other predators. These diverse origins of the bird bones have importantimplications for interpreting former avian distributions. Copyright © 2014 John Wiley & Sons, Ltd.

Key words: archaeology; avian distribution; bird bones; bird pellets; coastal settlements; fishing by-catch;Scotland

Introduction

Bird remains are recovered on many excavated settle-ment sites around the coast of Scotland. Typically, awide range of species is present of which many are rep-resented by only a few bones. While most discussionhas focused on the birds as food resources, some spe-cies clearly had a different origin. In this respect,remains of birds are unlike mammals and fish, whichare much more likely to be exclusively of food.The aim of this paper is to discuss reasons for the

diversity of species present. The records from archaeo-logical sites are a valuable source of information on pastavian distributions, but it is important to bear in mindthat bird bones from archeological sites do not reflectthe avifauna of the local environment directly. Theyare present because they were caught by people orother predators (Morales, 1993; Serjeantson, 2009,365–6). The examples here are taken from coastal sitesin the west and north of Scotland, particularly on theScottish islands, but the discussion is relevant for birdremains from any coastal sites anywhere in the world.

In Scotland people grew cereals and raised livestockfrom the Neolithic period (c. 4000 – 1500 BC) onwards,but the farmers who lived on the coasts and offshoreislands also fished and harvested seabirds (Serjeantson,1988; Best, 2014). While these activities are the sourceof many of the bird bones, some have other origins, bothanthropogenic and non-anthropogenic. In particular, Iwill argue here that certain species were caught inciden-tally by fishermen, a possible origin of bird bones thathas only briefly been touched on up to now.

Data and method

The data used in this survey are the species present andnumbers of identified bird bones from 25 assemblagesfrom 15 archaeological sites dating from the Neolithicto the Late Medieval period (Table 1). Other thanCrosskirk, which is on the north coast of Scotland,the sites are in the Orkney Islands and the Hebrides(Figure 1). Some assemblages are published but listsof identified bones were kindly supplied by some ana-lysts in advance of publication (Table 2).Assemblages with 50 or more identified bones were

included. The number of avian species was calculatedin relation to the number of identified bones (NISP).

* Correspondence to: Dale Serjeantson, University of Southampton -Archaeology, Avenue Campus School ofHumanities, Southampton, HampshireSO17 1J, United Kingdom.e-mail: d.serjeantson@soton.ac.uk

Copyright © 2014 John Wiley & Sons, Ltd. Received 26 August 2013Revised 26 November 2013Accepted 6 December 2013

International Journal of OsteoarchaeologyInt. J. Osteoarchaeol. 24: 279–288 (2014)Published online 21 January 2014 in Wiley Online Library(wileyonlinelibrary.com) DOI: 10.1002/oa.2387

Table 1. Assemblages showing archaeological period, NISP and N species. Also shown are the numbers of species with 20 per centor more of identified bones, between 19 and 5 per cent, and fewer than 5 per cent. * Assemblage with major component of non-anthropogenic species

Assemblage Period NISP N species ≥20% 5–19% 0–5%

Bornais Mound 1 Norse 67 16 1 4 11Bornais Mound 1 Late Iron Age 315 19 2 0 17Bornais Mound 3 Norse 52 19 0 8 11Bu Broch* Early Iron Age 266 37 1 5 31Cille Pheadair Norse 641 39 0 8 31Crosskirk Iron Age 144 24 1 4 19Dun Vulan Early Iron Age 387 38 0 7 31Knap of Howar Neolithic 251 40 0 6 34Pool 6 Late Iron Age 107 18 1 5 12Pool 7 Viking 346 35 1 4 30Pool 8 Norse 155 19 2 3 14Quanterness* Neolithic 140 39 0 6 33Quoygrew Norse 457 28 0 8 20Skara Brae* Neolithic 107 40 0 3 37The Howe 7* Middle Iron Age 466 70 1 3 66The Howe 8* Late Iron Age 464 64 1 1 62Tofts Ness 1+2 Neolithic/EBA 214 29 1 4 24Tofts Ness 4* Early Iron Age 162 34 1 3 30Tofts Ness 6 Late Iron Age 65 21 0 6 15Tuquoy 11 Norse 64 10 2 4 4Udal II-IV Late Medieval 67 13 2 1 10Udal V-VI Medieval 82 11 1 2 8Udal VII-IX Norse 98 18 2 3 13Udal IXc-X Viking 112 25 0 6 19Udal X-XII Late Iron Age 108 24 1 7 12

Figure 1. Map showing location of sites discussed.

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The count of the number of species in an assemblage isnot straightforward. To be as consistent as possible, Icounted the following pairs of species as one: cormo-rant (Phalacrocorax carbo) and shag (P. aristotelis), herringand lesser black-backed gull (Larus argentatus, L. fuscus),redshank and greenshank (Tringa totanus, T. ochropus).The large grey geese, including possible domesticgeese, were also counted as one species. Doubtful andpositive identifications were included.

Results

The percentage of birds was calculated as a percentage ofbirds and mammals for a subsample of the assemblages(Table 3). Bird bones invariably make up only a relativelymodest percentage of mammals and birds together. Theyare only about 2–3 per cent of the total in prehistoricassemblages though the percentage is higher in assem-blages from the Viking period (c. AD 800 – 1100)

onwards. From this, we can see that birds did not makea major contribution to the diet of farmers around thecoast of Scotland, but they did make a significant minorcontribution.All assemblages in the survey have between 10 and 70

identified species (Table 1). They have between one and16 identified bones per species. To examine whether thediversity is related to sample size, the number of identi-fied bones per species is shown, arranged according tosize of assemblage (Figure 2). There is little or no corre-lation. Another possible reason for the variation is achange over time, so the same data are arranged byperiod in Figure 3, with the oldest sites at the base ofthe graph. We might expect greater diversity in earlyperiods, when the percentage of birds was fewer, butthere is also little or no correlation between diversityand age of the settlement. However, the assemblageswhich are least diverse, with more than 15 identifiedbones per species, (Cille Phaedair, Quoygrew and theLate Iron Age levels at Bornais Mound 1) all date fromthe Late Iron Age (c. AD 500–800) or later.

Table 3. Per cent birds of identified birds and mammals onScottish coastal sites, in approximate date order

Date Assemblage Per cent birds

Late Medieval Udal II–IV 6.4Late Norse Udal V–VI 9.0Norse Bornais Mound 3 7.0Norse Udal VII–IX 7.2Norse Pool 8 2.8Viking Pool 7 3.3Viking Udal IXc–X 5.6Late Iron Age Udal X–XII 0.7Late Iron Age Pool 6 2.3Late Iron Age Tofts Ness 6 1.3Neolithic/Early Bronze Age Tofts Ness 1+2 1.7

Table 2. Sites with bibliographic references

Assemblage Bibliographic reference

Bornais Mound 1 Cartledge, 2012Bornais Mound 3 Cartledge, 2005Bu Broch Bramwell, 1987Cille Pheadair Best and Cartledge,

Personal communicationCrosskirk MacCartney, 1984Dun Vulan Cartledge & Grimbly, 1999Knap of Howar Bramwell, 1983Pool Serjeantson, 2007aQuanterness Bramwell, 1979Quoygrew Harland et al., 2013Skara Brae Eastham & Ap Gwynn, Manuscript reportThe Howe Bramwell, 1994Tofts Ness Serjeantson, 2007bTuquoy Hamilton-Dyer, Personal communicationThe Udal Serjeantson, 1988; Serjeantson, 2013

0 10 20 30

Bornais Mound 3 (55)

Tuquoy 11 (64)

Tofts Ness 6 (65)

Bornais Md 1 Norse (67)

Udal II-IV (67)

Udal V-VI (82)

Udal VII-IX (98)

Pool 6 (107)

Skara Brae (107)

Udal X-XIII (108)

Udal IXc-X (121)

Quanterness (140)

Crosskirk (144)

Pool 8 (155)

Tofts Ness 4 (162)

Tofts Ness 1+2 (214)

Knap of Howar (251)

Bu Broch (266)

Bornais Md 1 LIA (315)

Pool 7 (346)

Dun Vulan (387)

Quoygrew (457)

The Howe 8 (464)

The Howe 7(466)

Cille Pheadair (641)

Figure 2. Number of identified bones per species, arranged accordingto assemblage size, largest at the top. Assemblage size in brackets.

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Copyright © 2014 John Wiley & Sons, Ltd. Int. J. Osteoarchaeol. 24: 279–288 (2014)

A second method of showing diversity is the per-centage of the assemblage comprised by each species(Table 1). In more than half of the assemblages (17)one or two species account for 20 per cent or more ofthe identified bones. These are likely to have beenthe subject of targeted harvesting or hunting. Numbersof bones of domestic chickens (Gallus gallus) have littleinfluence on the results. They may have been broughtto northern Scotland at the end of the Iron Age butwas certainly present in the Norse period (c. AD1100–1300). They only make up 20 per cent or moreof at Norse Tuquoy and Medieval levels at the Udal.Where chickens are present in other settlements, theyare scarce. Otherwise, seabirds are the main species.At the Howe, an Iron Age broch, the single most fre-quent bird is the starling (Sturnus vulgaris) but it is morelikely to have been raptor prey than human food.There is an intermediate group in which a few species

make up between more than four and fewer than 20 percent of identified birds. The birds in this group wereprobably acquired more casually. Again, most are

seabirds, but the group also includes ducks, geese, gamebirds and waders.In all assemblages, there is a large ‘tail’ of species that

account for fewer than 4 per cent of the total. It islikely either that these were acquired incidentally orwere caught for purposes other than food or are non-anthropogenic. The ‘tail’ has the greatest number of spe-cies where there is probably a component of raptor prey.Three assemblages illustrate these trends (Table 4).

Knap of Howar is a Neolithic settlement. There is nospecies with more than 20 per cent of identified bones.The guillemot (Uria aalge) and the great auk (Pinguinisimpennis) each make up more than 15 per cent of theassemblage and the more casual catches, with more thanfive per cent of identified bones, were the gannet (Morusbassanus), cormorant and shag. The fulmar (Fulmarusglacialis) also has more than 5 per cent, but the 17 bonesinclude a part-skeleton and are from a minimum of onlytwo birds. There are 35 further species. At the Udal inthe Late Iron Age, the target species was the gannet.There are seven further species with more than 5 per centof identified bones, including gulls, cormorants, auks andthe red grouse (Lagopus lagopus). The 18 further speciesinclude gulls, waders, corvids and passerines. The thirdexample, the assemblage from Pool (Phase 8) in Orkney,is from the Viking period. The target species were gan-nets, cormorants and shags (which were distinguishedat this site). Three further species have 5 per cent ormore and there are 14 species, including domesticchicken, with fewer than 5 per cent of identified bones.

Taphonomic effects

While preservation and recovery were good at the sitesconsidered, it is possible that differences in survival, recov-ery and identification strategies have affected the samples.There are some variations in survival between sites and oc-cupation levels. This can be seen in the sequence from theUdal. The diversity of birds is less in the uppermost levelsat the site (phases II–IV) than in earlier periods. Bones sur-vived less well in the uppermost levels, probably becausethey weremore severely eroded bywater percolation thanthose in the lower levels. Recovery also plays a part. Allthe assemblages in the survey were sieved, but some useda smaller mesh than others. The Udal, the first excavationin Scotland to use bulk sieving, used a mesh (>2mm) thatwould have allowed bones of passerines to pass through.Most of the other sites used a smaller mesh, which mayhave enhanced numbers of passerines.Analysts vary in the precision with which they iden-

tify elements to species. In view of natural size variationwithin species, it is very difficult to separate some closelyrelated species and some researchers do so with more

0 5 10 15 20 25 30

Knap of Howar (251)

Quanterness (140)

Skara Brae (107)

Tofts Ness 1+2 (214)

Tofts Ness 4 (162)

Bu Broch (266)

Crosskirk (144)

Dun Vulan (387)

The Howe 7(466)

Bornais Md 1 LIA (315)

Pool 6 (107)

The Howe 8 (464)

Tofts Ness 6 (65)

Udal X-XIII (108)

Cille Pheadair (641)

Pool 7 (346)

Quoygrew (457)

Udal IXc-X (121)

Bornais Md 1 Norse (67)

Bornais Mound 3 (55)

Pool 8 (155)

Tuquoy 11 (64)

Udal V-VI (82)

Udal VII-IX (98)

Udal II-IV (67)

Figure 3. Number of identified bones per species, arranged by approx-imate date, youngest at the top, as Figure 2.

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confidence than others, partly from individual skill andexperience and partly from the breadth of their referencecollection. Bramwell tended to identify ducks and passer-ines to species with more confidence than others, whichhas contributed to the long ‘tail’ of species at the Howebroch in Orkney. Cartledge distinguished more small

and medium waders than most. Their species lists aresometimes more diverse than those of other analysts.In spite of all these variables in survival, recovery and

identification strategies, in fact all the assemblagesdiscussed here are very diverse. The reasons must besought elsewhere.

Table 4. Number of identified bones from Knap of Howar, the Udal (phase XI–XIII) and Pool (phase 8)

Scientific name English name Knap of Howar Udal XI–XIII Pool 8

Cygnus cygnus Whooper swan 3Anser anser Greylag goose 12 5Anser sp. Grey goose NFI 4 1Branta bernicla/leucopsis Brent/barnacle goose 10Tadorna tadorna Shelduck 1Anas platyrhynchos Mallard 1 1Anas sp. Duck NFI 1Somateria mollissima Eider 3Melanitta fusca Velvet scoter 1Lagopus lagopus Red grouse 6Tetrao tetrix Black grouse 1Gallus gallus Domestic chicken 2 3Gavia stellata Red-throated diver 1Gavia arctica Black-throated diver 3Gavia immer Great northern diver 1Fulmarus glacialis Fulmar 17 2Pterodroma feae Fea’s petrel 1Puffinus puffinus Manx shearwater 1 7Puffinus sp. Shearwater NFI 1Morus bassanus Gannet 24 33 39Phalacrocorax carbo/aristotelis Cormorant/shag 23 8 27Tachybaptus ruficollis Little grebe 1Haliaeetus albicilla White-tailed eagle 1Buteo buteo Buzzard 1Porzana porzana Spotted crake 1Crex crex Corncrake 1Haematopus ostralegus Oystercatcher 1Charadriidae Wader NFI 7Calidris canutus Knot 1Pluvialis apricaria Golden plover 3Pluvialis squatarola Grey plover 1Gallinago gallinago Snipe 2Numenius arquata Curlew 5Tringa ochropus Greenshank 1Tringa erythropus Spotted redshank 2Tringa totanus Redshank 1 1Stercorarius sp. Skua NFI 6Rissa tridactyla Kittiwake 1Larus canus Common gull 2 1Larus fuscus/argentatus Lesser black-backed/herring gull 6 1 7Larus marinus Great black-backed gull 17 2 3Sterna sandvicensis Sandwich tern 1Uria aalge Guillemot 39 6Alca torda Razorbill 9 3 3Pinguinis impennis Great auk 35 2 1Cepphus grylle Black guillemot 4Alle alle Little auk 1Fratercula arctica Puffin 3 7 1Corvus frugilegus/corone Crow/rook 1Corvus corax Raven 1 1Alauda arvensis Skylark 2Turdus sp. Thrush family 1 2Sturnus vulgaris Starling 1Passeriformes Passerine NFI 1

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Discussion of possible origins

Capture from breeding colonies

The methods used for seabird fowling were describedby visitors to the Hebrides and Orkney from the16th century onwards and have been discussed by var-ious authors (Baldwin, 1974; Fenton, 1978; Beatty,1992; Randall, 2005; Serjeantson, 2013). Parties ofmen visited cliffs and offshore islands to harvest sea-birds at their breeding sites. The birds, like fish, couldbe dried and preserved. Bones of birds not yet fledgedand still at the breeding site – those that are recordedin the literature as the target of the hunt – have some-times been observed in assemblages (Best & Mulville,2014) but not as often as might be expected. Somehawking and hunting took place from Viking times on-wards. The sagas contain descriptions of how theNorse earls hunted with bow and arrow.

Trade and exchange

Seabirds were used as payment of rent in kind from atleast the Middle Ages onwards (Martin, 1716). Gannets,guillemots and fulmars were exported from the remoteSt Kilda islands, which are off the Outer Hebrides, andfrom other islands: manx shearwaters (Puffinus puffinus)were exported from Eigg and Mingulay and puffins(Fratercula arctica) were exported from the Shiants(Martin, 1716; Gray, 1871; Serjeantson, 2001; Best &Mulville, 2010). The gannets from Bornais on South Uistand the Udal are thought to have been obtained from StKilda or elsewhere as tribute or exchange, as gannets donot breed on North or South Uist (Clarke et al., 2012;Serjeantson, 2013).Falcons were caught and traded. According to Martin,

who wrote an account of the Hebrides at the end of the17th century, the chief of the island of Barra, ‘held hisland in vassalage of Sir Donald MacDonald of Sleat’ inSkye. As well as paying him 40 pounds in rent per annum,he also supplied a hawk ‘if required’ (Martin, 1716).

Caught incidentally while fishing

As well as the targeted catches, some birds were caughtincidentally during other daily activities. They repre-sent casual resources, as defined by Higgs & Vita-Finzi(1972). The most significant of these must have beenbirds that were caught as a bycatch of fishing. Thispossible origin for some birds has been largelyoverlooked in earlier discussions of seabird fowling(e.g. Serjeantson, 1988). However, Bramwell (1994)pointed out that some of the birds at the Howe did not

breed in Orkney so must have been caught at sea as theywintered around the coast and Harland et al. (2013)raised the possibility that the gannets from Quoygrewwere caught during fishing expeditions.Fishing in the Hebrides and Orkney complemented

the main agricultural activities. Until the end of thefirst millennium AD, most fishing took place close tothe shore and from the rocks (Martin, 1716; Fenton,1978, 533, Ceron-Carrasco, 2005) but from the 10thcentury onwards substantial and organized line fishingfor cod (e.g. Barrett, 1997) and net fishing for herringdeveloped (Ingrem, 2005).Line fishing has taken place from at least the Bronze

Age onwards in northern Europe (Clark, 1952, 84–89).Several different types of line were used in coastalScotland. A simple fishing line used from the shore inthe Hebrides had a float and four baited hooksattached to a wand or rod (Ceron-Carrasco, 2005,Fig. 5.4). Fishermen used single or multiple long lineswhen fishing for haddock, cod and ling. In Orkney,some lines had as many as 1000 baited hooks. The lineswere baited with shellfish, small fish or pieces of her-ring (Fenton, 1978, 570–584; Ceron-Carrasco, 2005).Birds were caught on these hooks as they tried to

take the bait, both accidentally and deliberately.According to Thomas Pennant, an 18th century travel-ler to the Hebrides, his boatman ‘had frequently taken[gannets] by placing a herring on a hook’ (Pennant,1809). The Reverend MacPherson, who made a studyof the methods used to catch birds all over the world,observed that ‘fishermen often wile away the tediumof ship life by fishing with hook and line for the largerkind of Petrels’. He even wrote that ‘I have amused my-self by catching an odd Fulmar on a hook baited with aherring’s tail’ (MacPherson, 1897, 482). Birds continueto be killed on fishhooks, though today they are anaccidental bycatch. Shearwaters are caught in largenumbers in the Mediterranean on long lines (Belda &Sanchez, 2001). A global survey by the British RSPBestimated that ‘at least 160,000 (and potentially inexcess of 320,000) seabirds are killed annually’ bylong-line fishing (Anderson et al., 2011).

Netting is also a very ancient skill (Clark, 1952, 44).People in Orkney and the Hebrides used seine nets andalso gaff nets, known in Orkney as poke nets (Fenton,1978, 537). A type of gill net has been used at leastfrom Viking times. MacPherson (p. 208) wrote that‘Gannets are often drowned in herring nets, even whenthese have been sunk at a depth of nine, ten or thirtyfathoms’. He also noted (p. 481) that ‘divers weresometimes entangled in fishing nets’.The danger to seabirds from modern fishing nets is

notorious (RSPB, 2010). In the northern hemisphere,

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the auks are especially vulnerable. Hundreds of sea-birds, mostly razorbill (Alca torda), are killed aroundthe English coast. In the vicinity of their breeding cliffsin Yorkshire, they become entangled in salmon nets(UKMPA, 2001). A survey of pelagic fisheries in theBaltic found that an average of between one and twobirds was entrapped in each kilometre of fishing neton each day of fishing. The species most often caughtthere are long-tailed duck (Clangula hyemalis), velvetscoter (Melanitta fusca) and guillemot (Kies & Tomek,1990). An RSPB survey (2010) estimated that alto-gether ‘a minimum of 90,000 and more likely100,000–200,000 birds drown every year in gill-nets,including divers and sea-ducks’.Other methods were also used. In Iceland, gulls

were snared. The snare was attached to a buoy or apiece of wood on which a small fish was placed as abait (MacPherson, 1897, 208). Small petrels, whichfeed on the ocean surface, were deliberatelyentangled. ‘It is a common amusement on sailingvessels to endeavour to capture Wilson’s Petrel andother little petrels. The modus operandi … consists oftying a number of long threads to pieces of cork orother floats, which are thrown into the sea in the stern

of the craft. … The Petrels fly in the wake of thevessel; consequently they often come into contactwith the threads and … the birds become entangled’(MacPherson, 1897, 478).The families and species, which were – and are –

most at risk of being caught by fishermen around thecoast of Scotland are the procellarids, gannets, cormo-rants, shags, gulls and auks. Divers and diving duckswere also vulnerable (Table 5).Though the written evidence for accidental – or

deliberate – catches by fishermen comes from the18th century onwards, the capture of birds as well asfish on lines and nets is likely to have an antiquity asold as the use of these techniques.

Other opportunistic fowling

There were other occasions when people might collectbirds during the course of their main activities. In theHebrides, cattle and sheep were taken away from thesettlement to hills for the summer, a small-scale formof transhumance. Red grouse, golden plovers (Pluvialisapricaria) and greylag geese (Anser anser) could be caughton the moorland where they bred and wintering swans

Table 5. Species recorded on one or more archaeological sites in Scotland that could have been caught with fishing gear. All breed innorthern Scotland other than those shown as ‘No’ in ‘Breeding status’; *formerly bred only on St Kilda; ± bred in Scotland until extinction

Family Species Breeding status

Anatidae Scaup (Aythya marila) NoEider (Somateria mollissima)Velvet scoter (Melanitta fusca) NoCommon scoter (Melanitta nigra) ?Long-tailed duck (Clangula hyemalis) NoRed-breasted merganser (Mergus serrator)Goosander (Mergus merganser) ?

Gavidae Great northern diver (Gavia immer) NoRed-throated diver (Gavia stellata)Black-throated diver (Gavia arctica)

Procellariidae Fulmar (Fulmarus glacialis) *Fea’s petrel (Pterodroma feae) NoManx shearwater (Puffinus puffinus)Sooty shearwater (Puffinus griseus) No

Sulidae Gannet (Morus bassanus)Phalacorcoracidae Cormorant (Phalacrocorax carbo)

Shag (Phalacrocorax aristotelis)Laridae Great black-backed gull (Larus marinus)

Herring gull (Larus argentatus)Lesser black-backed gull (Larus fuscus)Common gull (Larus canus)Kittiwake (Rissa tridactyla)Sandwich tern (Sterna sandvicensis)

Stercoraridae Great skua (Stercorarius skua)Alcidae Little auk (Alle alle) No

Guillemot (Uria aalge)Razorbill (Alca torda)Great auk (Pinguinis impennis) ±Black guillemot (Cepphus grylle)Puffin (Fratercula arctica)

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and ducks could have been caught on inland lochs. Younglivestock were taken to offshore islands for summer graz-ing. Pennant noted how the sailor who carried him to anoffshore island went ‘in search of sea fowl’ while heawaited the return of his passengers (Pennant, 1809, 277).

Accidentally carried to the settlement

People may even have introduced bird bones to settle-ments accidentally. The agricultural soils around thesettlements were fertilized each year by the applicationof seaweed, which was collected from the shore(Martin, 1716). Dead birds are washed up on the shore,especially after a storm, the causes of death beingstarvation, injuries from seals, injuries from fishingtackle and (today) marine pollution. The bird, or itsscavenged skeleton, ends up on the shoreline with theseaweed. The accidental import of bird bones with sea-weed is a possible origin for some bones.

Bird pellets and discards

After settlements were abandoned – possibly even whilethey were still in use – buildings were used as roostsand breeding sites. Buildings were important roostingperches in island and coastal environments that heldfew trees. Many bird pellets, ejected below roosts, con-tain bones of other birds. The species which would havediscarded bones or pellets with bird bones include theowls, white-tailed eagle (Haliaeetus albicilla), sparrowhawk(Accipiter nisus), (present today in Orkney but not theHebrides) and the peregrine (Falco peregrinus). The largegulls and corvids kill and scavenge smaller birds, after-wards to drop bones and eject pellets.The assemblage from Bronze Age Tofts Ness

(Serjeantson, 2007b), which included bones of dozensof passerines and small waders, is thought to be mainlyfrom bird pellets. This was supported by the fact thathundreds of Orkney voles were present in the same de-posits. The short-eared owl (Asio flammeus) is the mostlikely predator. Though mostly preying on voles andother rodents, it turns to small birds, including smallwaders, in coastal environments in winter (Glue,1977). More than half of the identified bones from theNeolithic tomb of Quanterness are passerines; theyinclude part-skeletons of a wryneck (Jynx torquilla) anda skylark (Alauda arvensis) (Bramwell, 1979). As discussed,the many starlings and other passerines in the brochs atthe Howe broch were probably raptor prey, as were thestarlings in upper, post-broch, deposits at Bu Broch.Bones in owl pellets are often well-preserved as theyare protected by the feathers with which they wereejected. At the Neolithic settlement of the Links of

Noltland in Orkney, passerine bones were better pre-served than those of larger birds (Armour-Chelu, 1988).

Natural deaths

Some birds may have died natural deaths on archaeo-logical sites. Commensals such as crows might be pres-ent when a settlement was in use and there are manyother species, as discussed, that would use the buildingsafter they were abandoned. Remains of owls and otherraptors are sometimes found in such contexts as well asremains of their prey. The part-skeletons of short-earedowls within Howe broch and Tofts Ness are thought tohave been casualties.

Cats

Domestic cats were introduced to the west of Scotlandfrom the middle of the 1st millennium AD. From thistime on, it is possible that remains of small birds mighthave been caught by cats, but the only recordedevidence for what are probably feline tooth marks areon the bones of large birds (Serjeantson, 2013, fig. 8.2).This catalogue is not exhaustive but it is a reminder of

the many possible origins of bird bones found on coastalsites. Some were the source of many birds but others areunlikely to have provided more than one or two bones.

Conclusions: re-interpretations of theorigins of some individual species

With the range of possible origins of bird bones inmind, we can re-interpret the presence and relativenumbers of certain species.Species that do not breed around Scotland or that

breed only far distant from the settlement where theywere found cannot have been caught at the breedingsites. The environment and climate have changed inthe past 5000 years, but breeding distributions haveprobably not changed drastically over the period(Kitchener, 2007). The distribution of breeding birdsin the recent past (Snow, 1971; Harrison, 1988;Gibbons et al., 1993) is taken here as a general guideto their distribution in the historic past.Goosander (Mergus merganser) has been recorded at

some sites. It breeds in mainland Scotland but not inthe islands today. Other diving ducks, including thecommon scoter (Melanitta nigra) and the velvet scoter(M. fusca), also recorded in small numbers, are veryscarce breeding birds today. The goosander could havebeen caught at sea or on fresh water but it is likely that

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the scoters were caught at sea. The great northern di-ver (Gavia immer) must also have been caught at sea asit does not breed in Scotland. The same may be truefor the black-throated diver (G. arctica) which has beenrecorded in Orkney. It breeds in the Hebrides todaybut not in Orkney. However, it is also possible thatthe various divers formerly bred more widely.Fulmars are not as frequent as other seabirds, but most

assemblages include one or two bones. Until the end ofthe 19th century, the only known breeding site of thefulmar in the British Isles was St Kilda (Snow, 1971, 9).The numbers found have suggested to some authors thatthe fulmar bred more widely in the prehistoric past(Yalden & Albarella, 2008, 93). Fulmars disperse widelyto feed, and as they specialize in discards of fishermen,so they are very likely to have been caught by fishermen.Another possible origin is trade from St Kilda.Remains of a gadfly petrel have been found on three

sites in Scotland (Serjeantson, 2005). Recent DNAanalysis has shown that they are Fea’s petrel (Pterodromafeae) (Brace et al., in preparation). This species has notbeen recorded in Britain until recently (Snow, 1971;Else & Butcher, 2011) and today breeds no nearer thanthe island of Bugio off Madeira. These too were prob-ably captured in fishing nets.The manx shearwater breeds on the island of Rhum

today and formerly bred on other islands aroundScotland (Serjeantson, 2013). While some manx shear-waters were undoubtedly taken from breeding sites,many from settlements distant from breeding sites aremore likely to have been caught with fishing gear. Thisspecies was also traded.Though small offshore islands in the north and west

of Scotland hold important breeding sites for gannets,the number of colonies was (and is) limited. From thebeginning of the 2nd millennium AD, the colonieswere in the ownership of different overlords, so accessto gannets was restricted (Serjeantson, 2001) and fish-ermen too probably caught many of these. Gannets,as discussed, could also have been obtained throughtrade.The little auk (Alle alle) could not have been caught

at the breeding site as it breeds in the Arctic. It is pres-ent around the shores of Scotland in winter so was mostlikely caught in herring nets. As it is prone to beingwrecked, it might alternatively have been introducedto settlements in seaweed.Bird bones, as discussed, hold important information

on both past human activities in the past and on formeravian distributions. When interpreting the significanceof bird bones from sites such as those discussed here, itis essential to understand the potential role of avianpredators as well as human hunting. It is also important

to bear in mind the possible means by which birdbones could have become deposited in settlementsaccidentally. While deliberate and targeted captureby people accounts for many bird bones, several wereprobably acquired as a bycatch of fishing.

Acknowledgements

I would like to thank Julia Best and Sheila Hamilton-Dyer for allowing me to quote unpublished results. Ialso thank Zbigniew Bochenski for comments that haveimproved this paper.

References

Anderson ORJ, Small CJ, Croxall JP, Dunn EK, Sullivan BJ,Yates O, Black A. 2011. Global seabird bycatch in long-line fisheries. Endangered Species Research 14: 91–106.

Armour-Chelu M. 1988. Taphonomic and cultural informa-tion from an assemblage of Neolithic bird bones fromOrkney. The Exploitation of Wetlands, P Murphy, C French(eds). British Series 186. BAR: Oxford.

Baldwin JR. 1974. Sea bird fowling in Scotland and Faroe. FolkLife 12: 60-130. DOI: 10.1179/043087774798240992

Barrett JH. 1997. Fish trade in Norse Orkney and Caithness:a zooarchaeological approach. Antiquity 71: 616-638.

Beatty J. 1992. Sula: Seabird-hunters of Lewis. Michael Joseph:London.

Belda EJ, Sanchez A. 2001. Seabird mortality on longlinefisheries in the western Mediterranean: factors affectingbycatch and proposed mitigating measures. BiologicalConservation 98(3): 357–363. DOI: 10.1016/S0006-3207(00)00178-6

Best J, Mulville J. 2010. The fowling economies of the ShiantIsles, Outer Hebrides: resource exploitation in a marginalenvironment. Birds in Archaeology: Proceedings of the 6th meetingof the ICAZ Bird Working Group, Groningen, W Prummel, JZeiler, D Brinkhuizen (eds). Barkhuis: Groningen; 87–96.

Best J, Mulville JA. 2014. A bird in the hand: data collationand novel analysis of avian remains from South Uist,Outer Hebrides. International Journal of OsteoarchaeologyDOI: 10.1002/oa.2381

Bramwell D. 1979. The bird bones. Investigations in Orkney, CRenfrew (ed.). Society of Antiquaries: London; 138–143.

Bramwell D. 1983. Bird bones from Knap of Howar, Orkney,pp. 100–103 in ‘Excavation of a Neolithic farmstead atKnap of Howar, Papa Westray, Orkney’ Ritchie, A. Pro-ceedings of the Society of Antiquaries of Scotland 113: 40–121.

Bramwell D. 1987. The bird remains. Bu, Gurness, and theBrochs of Orkney, Vol. 1: Bu, J Hedges, B Bell, B BallinSmith (eds). British Series 163. BAR: Oxford; 8.

Bramwell D. 1994. The bird remains. Four Millennia of OrkneyPrehistory: The Howe excavations 1978-1982, B Ballin Smith

287Diverse Origins of Bird Bones from Scottish Coastal Sites

Copyright © 2014 John Wiley & Sons, Ltd. Int. J. Osteoarchaeol. 24: 279–288 (2014)

(ed.). Monograph 9. Edinburgh: Society of Antiquaries ofScotland; 153–157.

Cartledge J. 2005. Bird bone. A Norse Farmstead in the OuterHebrides: Excavations at Mound 3, Bornais, South Uist, NMSharples (ed.). Oxbow: Oxford; 145.

Cartledge J. 2012. Birds. A Late Iron Age Farmstead in the OuterHebrides. Excavations at Mound 1, Bornais, South Uist, NMSharples (ed.). Oxbow: Oxford; 195–196.

Cartledge J, Grimbly C. 1999. The bird bones. Between Landand Sea: Excavations at Dun Vulan, South Uist, M ParkerPearson, NM Sharples, J Mulville, H Smith (eds). SheffieldAcademic Press: Sheffield; tables 10.51.10.52, 10.53.

Ceron-Carrasco R. 2005. ‘Of Fish and Men’ (‘De iasg agusdhaione’): a study of the utilization of marine resources as recoveredfrom selected Hebridean archaeological sites. British Series 4000.BAR: Oxford.

Clark JGD. 1952. Prehistoric Europe: the economic basis.Cambridge: Cambridge University Press.

Clarke A, Cartledge J, Gale R, Serjeantson D, Sharples NM.2012. Exotic imports. A Late Iron Age Farmstead in the OuterHebrides: Excavations at Mound 1, Bornais, South Uist, NMSharples (ed.). Oxbow: Oxford; 250.

Eastham A, Ap Gwynn I. Manuscript report. National Museumsof Scotland. For publication in Skara Brae excavations,D Clarke (ed.).

Else R, Butcher R. 2011. Birds recorded at the Observatory in2011.North Ronaldsay Bird Observatory Bird Report 2011, vol. 1:13-70.

Fenton A. 1978. The Northern Isles. John Donald: Edinburgh.Gibbons DW, Reid JB, Chapman RA. 1993. The New Atlas ofBreeding Birds of Britain and Ireland: 1988 – 1991. Poyser:London.

Glue D. 1977. Feeding ecology of the Short-eared Owl inBritain and Ireland. Bird Study 24: 70–78.

Gray R. 1871. The Birds of theWest of Scotland. Oxford UniversityPress: Oxford.

Harland JF, Briscoe RA, Andrews JI, O’Connor TP, BarrettJH. 2013. Fowling: the bird bone. Being an Islander: Produc-tion and identity at Quoygrew, Orkney, AD 900-1600, J Barrett(ed.). Cambridge: McDonald Institute for ArchaeologicalResearch; 157–161.

Harrison CJO. 1988. The History of the Birds of Britain. Collinsand Witherby: London.

Higgs ES, Vita-Finzi C. 1972. Prehistoric economies: a terri-torial approach. Papers in Economic Prehistory, ES Higgs(ed.). Cambridge: Cambridge University Press; 27-36.

Ingrem C. 2005. Resource exploitation: the sea: fish. ANorse Farmstead in the Outer Hebrides: Excavations at Mound3, Bornais, South Uist, NM Sharples (ed.). Oxbow:Oxford; 157–158.

Kies B, Tomek T. 1990. Bird mortality in fishing nets in theGulf of Gdansk, Polish Baltic Coast. Pelagicus 5: 23–27.

Kitchener A. 2007. The fossil record of birds in Scotland.The Birds of Scotland, RW Forrester, IJ Andrews, CJMcInerny, RD Murray, RY McGowan, B Zonfrillo, MWBetts, DC Jardine, DS Grundy (eds.). Scottish Ornitho-logical Club: Aberlady.

MacCartney E. 1984. Analysis of faunal remains. Excavationsat Crosskirk Broch, Caithness, H Fairhurst (ed.). Monograph 3.Society of Antiquaries of Scotland: Edinburgh; 133–147.

MacPhersonHA. 1897.AHistory of Fowling. Edinburgh: Douglas.Martin M. 1716. A Description of the Western Islands of Scotland.London: Bell. https://archive.org/stream/descriptionofwes00mart#page/n3/mode/2up

Morales A. 1993. Ornithoarchaeology: the various aspects ofthe classification of bird remains from archaeological sites.In Special issue ‘Archaeornithology: birds and the archae-ological record’. Archaeofauna 2: 1–13.

Pennant T. 1809. A tour in Scotland and voyages to theHebrides in 1772. In Pinkerton, J (ed.) Voyages and Travelsin all parts of the World, Vol. III. London: 171–570.

Randall J (ed.) 2005. Traditions of Seabird Fowling in the NorthAtlantic Region. Islands Book Trust: Stornaway.

RSPB. 2010.Marine and coastal policy: seabird bycatch, 14April.Serjeantson D. 1988. Archaeological and ethnographic evi-dence for seabird exploitation in Scotland. Archaeozoologia2(1,2): 209–224.

Serjeantson D. 2001. The great auk and the gannet: a prehis-toric perspective on the extinction of the great auk.International Journal of Osteoarchaeology 11(special issue):43–55. DOI: 10.1002/oa.545

Serjeantson D. 2005. Archaeological records of a gadflypetrel Pterodroma sp. from Scotland in the first millenniumAD. Feathers, Grit and Symbolism: Birds and humans in the ancient,old and new worlds, G Grupe, J Peters (eds.). DocumentaArchaeobiologiae 3: 235–246.

Serjeantson D. 2007a. The bird bones. Investigations in Sanday,Orkney. Vol. 1: Excavations at Pool, Sanday, J Hunter (ed.).The Orcadian: Kirkwall; 279–285.

Serjeantson D. 2007b. Bird bones. Investigations in Sanday,Orkney. Vol. 2: Tofts Ness, Sanday, SJ Dockrill (ed.). TheOrcadian: Kirkwall; 216–227.

Serjeantson D. 2009. Birds. Cambridge Manuals in Archaeol-ogy. Cambridge University Press: Cambridge.

Serjeantson D. 2013. Farming and Fishing at the Udal, OuterHebrides, AD 600 to 1700. Archaeology Monograph 6.Highfield Press: Southampton.

Snow DW (ed.). 1971. The Status of Birds in Britain and Ireland.Blackwell: Oxford.

UKMPA. 2001. The UK Marine Special Areas of Conserva-tion Project. http://www.ukmarinesac.org.uk/activities/fisheries/f3_1.htm (accessed 9 April 2013).

Yalden D, Albarella U. 2008. The History of British Birds.Oxford University Press: Oxford.

288 D. Serjeantson

Copyright © 2014 John Wiley & Sons, Ltd. Int. J. Osteoarchaeol. 24: 279–288 (2014)