605

ANIMAL BONES FROM THE VIKING TOWN OF BIRKA, SWEDEN Bengt WIGH*

Summary Résumé Zusammenfassung In the spring of 1990 began the Ossements animaux de la cité viking de Die Tierknochen aus der Wikingerstadt largest archaeological investigations Birka, Suède. Birka, Schweden. thus far of the first urban centre in Swe­ Au cours du printemps 1990, ont Die bisher grojJten Ausgrabungen in den, called Birka. During the six years débuté les plus grandes fouilles archéo­ Birka, der frühesten Stadt Schwedens of the excavation, an archaeozoologist logiques effectuées à ce jour du premier begannen 1990 und wurden 1995 abge­ has been employed on site to organize centre urbain de Suède : Birka. Pendant schlossen. Wdhrend dieser Jahre sor­ and begin analysis of more than 5.5 les six années de fouilles, un archéozoo­ tierte und analysierte ein eigens ange­ tonnes of animal bones. This osteologi­ logue a été employé sur le site pour stellter Archdozoologe das Knochenma­ cal material has proved to be unique, organiser et commencer l'étude de plus terial. Bis heute ( 1994) sind von den bath qualitative/y and quantitative/y, in de 5,5 tonnes d'ossements animaux. Ce Archdologen 5.5 Tonnen Tierknochen the Swedish Viking Period. The analysis matériel ostéologique s'est révélé ausgegraben worden. Dies ist das bisher of the material (which has just begun) unique, à la fois sur les plans qualitatif grojJte und am besten erhaltene Materi­ will give us both new and extended et quantitatif, pour la période viking sué­ al aus der Wikingerzeit Schwedens. Die knowledge of Viking Period domestic doise. L'analyse du matériel vient de Analyse der Tierknochen aus Birka wird animais and wild fauna in Central Swe­ commencer ; elle livrera une connais­ uns neue und gesicherte Erkenntnisse den. This paper will present some of the sance nouvelle et approfondie des ani­ zur Haus- und Wildtieifauna der Wikin­ new results, together with some future maux domestiques de la période viking et gerzeit Schwedens liefern. Dieser Bei­ plans. de la faune sauvage de Suède centrale. trag stellt einige neue Resultate und für Cet article présente une partie des résul­ die Zukunft geplante Aktivitdten vor. tats ainsi que les perspectives d'avenir.

Key Words Mots clés Schlüsselworte Sweden, Viking Age, Early town-sett­ Suède, Époque viking, Premières ins­ Schweden, Wikingerzeit, Frühe Stadt, lement, Meat production, Fur-bearing tallations urbaines, Production de vian­ Schlachttiere, Pelztiere. mammals. de, Mammifères à fourrure.

Birka was situated on a small island, Bjürkêi, in Lake the craftsmen of the town manufactured a great amount and Malaren, about 30 km west of modern Stockholm (fig. l). variety of goods which formed the basis of Birka's econ­ The town of Birka was founded during the middle of the omy (Ambrosiani, 1991). eighth century AD, and existed barely 200 years before the Bjürkêi, upon which Birka Jay, had a very limited sur­ site was deserted around AD 975 in favour of a new town, face area during the Viking Period. Today the island is Sigtuna. When Birka was at its largest, it has been calcu­ somewhat larger, as a result of a land rise of 5 m over the lated that between 700 and 1000 people lived and worked past 1000 years. This implies that during Birka's occupa­ there. The site came to :be a central point for trade to and tion, the inhabitants were forced to import virtually all food from the Svea kingdom; V arious artefacts have been found from outside. As late as the nineteenth century, when (Arabian silver coins, Finnish and Slavic ceramics, and Bjürkêi was most intensively farmed, the area could supply cowrie shells from the Irrdian Ocean, among others) which meat and grain for only about 30 people (Ambrosiani and indicate very extensive and long-distance trade. Moreover, Eriksson, 1991 ).

* Birkagriivningen, Box 5405, S-114 84 Stockholm, Sweden.

ANTHROPOZOOLOGJCA. 1997, N° 25, 26 - 606

\ line. A jetty from the tenth century was found. These exca­ vations were the first in Birka to be carried out stratigraphi­ cally, which also implied that the extensive animal bone collection was more exactly datable (Ambrosiani et al., 1973). The problem with the finds from Stolpes excava­ tions is that they lack exact dating. Stolpe dug long trenches through the urban area without taking any notice of the sequence of layers. Parts of the material (ca 10%) from the 1969-71 exca­ vations have been analysed and published in a preliminary report (Ericson et al., 1988). Also, parts of the large amounts of bird bone material have been specially treated (Ericson, 1987a, 1987b). The bird bones indicate large scale hunting of migratory birds, particularly duck, during the Viking Period. The hunting was carried out during spring, in the outer areas of the Stockholm archipelago. Finds from Sigtuna indicate that the same method contin­ ued to be used after the end of Birka (Jonsson, 1989: 54ff). çr So, in 1990 it was time for the largest excavations since the time of Hjalmar Stolpe. During six years, an area yThe Ba/tic of 350 m2 with 2.5 m thick culture-layers was to be exam­ ined. The goal for this excavation was to establish some­ thing of the internai structure and earliest phases of the Fig. 1: Birka and its location in Sweden. town. This time, modern measurement techniques and computer programs have been used to help with the inves­ As early as 1871, the zoologist Hjalmar Stolpe carried tigation of the very complex stratigraphy (Ambrosiani, out the first archaeological investigations of Birka, in the 1992: 83ff). There is very little preserved wood from the so-called "Black Earth" (this is the local name for the very buildings, which means that the interpretation of the char­ charcoal - and ash - rich urban area). Stolpe had corne to acter of the different deposits is even more important. The Birka to investigate what he believed to be a naturally high animal bones have, therefore, great significance for the occurrence of amber, which proved to be the remains of the archaeological interpretations. During the five years which Viking town. Subsequently, he concentrated on archaeol­ the excavations have run, over 3000 layers have been ogy. He dugon Bjürko for 24 years, and during his excava­ recorded. Working with ail these takes time, but with the tions in the urban area, he began the first collection of ani­ help of computers, it is calculated that the work will be mal bones from the site (Clarke and Ambrosiani, 1993: complete during 1997. This is true also of the anal y sis of 67ff). In total, 1.5 tonnes of animal bone have been saved osteological material, which will be based on both archaeo­ from Stolpe's excavations (Wigh, 1994: 34). As a zoolo­ logical and osteological objectives. The very precise strati­ gist, Stolpe also made a certain amount of species identifi­ graphie excavation technique will make it possible to study cations, and wrote short summary reports on the bone indiviual households and their food waste, perhaps even at material (Stolpe, 1872: 11-17; 1873: 62-75). However, he a seasonal level, for the first time. did not have time to carry out more detailed analyses, . There is a virtual 100% retrieval rate for bone from the which he regrets in his reports (Stolpe, 1873: 62). present excavations. Ali soi! is water-sieved in a 3 mm The next large archaeological project in Birka was not sieve, from which ail visible bone is picked, and soi! sam­ to take place for another 100 years. Hjalmar Stolpe had ples are ~aken from each layer. To check the representativ­ established that the urban area consisted of very compli­ ity of the bone collection, random tests have been made on cated stratified deposits, and therefore no further investiga­ the contents of the soi! samples. These show that ail animal tion was permitted before excavation techniques and species found are represented in the 3 mm sieve, and no knowledge of Viking Period structures had been improved. extra species are found in the soi! samples. The only new During the three years between 1969 and 1971, archaeolo­ information added from the soi! samples was a number of gists investigated a small area on the Viking Period water vertebrae from smaller herring.

ANTHROPOZOOLOGICA. 1997, N' 2 5, 26 Section IV· Postpalaeolithic Europe I 607

Table 1: Identified species from Birka (Stolpe, 1872, 1873; Ericson et al., 1988 with additions).

Domesticated animais White fish (Coregonus sp.) Cattle (Bos taurus) Cod (Gadus morhua) Horse (Equus caballus) Burbot (Lota Iota) Pig (Sus scrofa dom.) Pope (Acerina cernu) Sheep (Ovis aries) Rudd (Scardinius erythrophtalmus) Goat (Capra hircus) Dog (Canisfamiliaris) Birds Cat (Felis catus) Great crested grebe (Podiceps crislalus) Cormorant (Phalacrocorax carbo) Domestic fowl (Gallus gallus) Domestic geese (Anser anser dom.) Whooper swan (Cygnus cygnus) Greylag goose (Anser anser) Fur-bearing animals Shelduck (Tadorna tadorna) Red fox (Vulpes v,ulpes) Mallard (Anas plathyrhynchos) Red squirre! (Sei urus vulgaris) Eider (Somateria mollisima) Pine-marten (Martes martes) King-eider (Somateria spectabilis) Brown bear (Ursus arctos) Long-tailed duck (Clangula hyemalis) Wolf (Canis lupus) Common scoter (Melanitta nigra) Lynx (Lynx lynx) Velvet scoter (Melanittafusca) Beaver (Castor fiber) Goosander (Mergus merganser) Ermine (Mustela erminea) Red-breasted merganser (Mergus serrator) Wolverine (?) (Gulo gu/o) Crow (Corvus corone cornix) Hare (Lepus 1imidus) Raven (Corvus corax) Badger (Meles me/es) Golden-eagle (Aquila chrysaetos) Otter (Luira luira) White-tailed eagle (Haliaetus albicilla) Polecat (Muslela pulorius) Sparrowhawk (Accipiter nisus) Peregrinc (Falco peregrinus) Pests Capercaillie (Tetrao urogallus) Black rat (Rclttus Rattus) Black grouse (Lyrurus tetrix) Water vole (Arvicola terrestris) Arctic skua (Stercorarius parasitus) Field vole (Microtus agrestis) Herring gull (Larus argentatus) House mouse (Mus musculus) Great black-backed gull (Larus marinus) Antier Razorbill (Alca torda) Elk (Alces alces) Black guillemot (Cepphus grylle) Reindeer? (Rangifer tarandus) Wood pigeon (Columba palumbus) Roe-deer ( Capreolus capreolus) Swallow (Hirundo rustica) Jackdaw (Corvus monedula) Fish Song-trush (Turdus philomelos) Perch (Perca fluvia1ilis) Pike (Esox lucius) Artefacts Pike-perch (Lucioperca Lucioperca) Whale (bone) Tench (Tinca linca) Walrus (ivory) Ide (Leusiscus idus) Amphibians Roach (Rutilus rutilus) Frog (Rana sp.) Bream (Abramis brama) Toad (Bufo sp.) Asp (Aspius aspius) Herring (Clupea harengus) Other mammals Sturgeon (Acipenser sturio) Sea! (Phoca sp.) Eel (Anguilla anguilla) Human bones (Homo sapiens)

After the bones have been washed in the water sieve, sible to study the species in the bone content of each layer they are dried and then taken over by the osteologist. Ali out in the field, and to note the presence of unusual species the material from the respective layers is roughly sorted in or amounts of bone. It is possible to adapt the digging the field into large taxonomie groups: cattle, horse, pig, according to need and osteological interest. sheep/goat, bird, fish, and game. The bone from each group Avery large number of animal species has been identi­ is then weighed. The result is then entered in a database for fied from the three largest excavations in Birka (Stolpe, further analysis (Wigh, 1995: 88-89). It is thus already pos- 1872, 1873; Ericson et al., 1988). Bone from most of the

ANTHROPOZOOLOG/CA, 1997. N° 25. 26 608

41% It is, however, not yet possible to date this transition to beef more exactly, as both the osteological and the strati­ 44% 19% graphie analyses have just begun. Therefore it is not yet possible, either, to explain the reasons for such a large 14% change in food intake. One problem is that we do not now know how trade 45% with the town's hinterland was regulated during the Viking Period. Food delivery may have been a form of tax or trib­ 8th cent. East part 9th cent. Northwest part ute to the local king, who then distributed provisions in the town. It may also have been a question of production from 41% the urban residents own, or their kinship's farms in the vicinity. • Cattle A hypothesis which may explain why a change took place in food intake is that, during a time near the begin­ 18% 1111 Sheep ning of Birka's existence, it was still possible for the urban D Pig residents to keep a number of smaller grazing animais on the island. During the ninth century Birka expanded so lOth cent. Jetty much that the population was forced to shift totally to importing meat, then beef. Another reason for the differ­ ence between these two groups may be that the oldest lay­ Fig. 2 : Distribution of cattle, sheep and pig in Birka. ers corne from a casting workshop, while the younger are (% number of fragments) primarily domestic in character. The food consumption pat­ terns may therefore have been different, as a result of the Swedish mammals, and many bird and fish species, has occupants' different economic conditions. During 1995, the been found. Amphibians are, however, very rare (tab. 1). stratigraphy of the casting workshop from the end of the Certain species are only represented in the form of horn or eighth and beginning of the ninth centuries will be investi­ antlcr as raw material for manufacturing: elk, and possibly gated, and then, perhaps, these questions may be answered. rcindeer (Stolpe, 1873: 68), or artefacts: whale, and possi­ In contrast to the pasture animais, it appears from bly walrus. many finds of immature pig bones that pigs may have been So far, it has not been possible to begin detailed stud­ kept in town during the whole of Birka's existence. The ies of the bone in the different layers apart from the weight proportion of pig bones is relatively constant over time. of the contents. The archaeological results are as yet not The number of pigs bred, however, was not enough alone ready. However, it is possible to do a rough division of the to support the population. For extra meat and eggs, the material into two groups from the stratigraphy: Birka occupants had hens and geese. Among the wild mammal finds, the bones of Swedish 1: bone from the eastern part of the excavations, fur-bearing animais clearly dominate. It is known from his­ primarily from layers associated with bronze cast­ torical sources that there was a large trade in furs in Swe­ ing, dating to around AD 750-800. den during the Viking Period, but never before have such amounts of fur-bearing animal bone been found. This is, 2: bone from the north-western part of the excava­ then, the first time that it has been possible to document tions, from domestic-type deposits dating to ca. this widespread trade with the help of archaeological finds AD 800 and later. (Ambrosiani and Eriksson, 1994: 46). What has now been found during the excavations is thousands of phalanges and The species distribution for the two periods is very dif­ metapodes from, primarily, fox, pine marten and squirre!. ferent. A substantial change in diet happened around the The furs have been brought to Birka untanned, with the beginning of the ninth century (fig. 2), from a dependence paws attached. In the town, craft workers have eut off the upon meat from sheep in the earlier time to a dominance by paws and worked the furs for sale. Left behind in rubbish meat from cattle in the later layers. This is also supported deposits are the articulated bones from complete paws. by the results from the 1969-71 excavations of the tenth Lesser amounts of paw bones from other fur-bearing ani­ century jetty area. mais have also been found, for example bear, lynx, hare,

ANTHROPOZOOIDGICA. 1997, N' 25. 26 Section IV: Postpalaeolithic Europe 1 609 polecat, beaver and wolverine. In contrast to the later town rat bones, though a lesser number of mouse bones have of Sigtuna, it does not appear that cat pelts have been been found. Mouse occurs with black rat sporadically in ail brought here. A great number of crania and bones from the types of the more recent la y ers. extremities of cats in Sigtuna bear eut marks from skinning It must also be said that fish and bird remains occur in (Harding, 1991: 106). No cat bones from Birka have simi­ great amounts, and are to a large extent undamaged by lar visible marks. Certain cats from Birka seem to have 1000 years in Birka's soi!. Around a tenth of the identified been left or even buried whole within the area. Of hare bone weight is fish and bird bone, which, in fragment bones, primarily phalanges and metapodes have been count, probably exceeds the number of ail other animal found, which indicates that the skin was more important bones. So far, no analysis or count of fish or bird bone than the meat. fragments has been carried out. The birds which dominate It seems that the fur trade existed from the time of are ducks, as mentioned above, and among the fish, fresh Birka's foundation to its abandonment. Primarily squirre! water species from the lake around the island are most and fox bones have been found in the very earliest layers, common. A considerable number of herring have also but the actual furrier' s workshop has not been found within corne to the island. It is as yet unclear whether the water of the area of the excavation. Fur-bearing animal bones have Lake Malaren was sufficiently brackish in the Viking been found spread over the whole area, but are more concen­ Period that there were local shoals of herring. Further geo­ trated in rubbish layers on the roads between the house plots. logical studies will answer this question. We do not now know whether tanning of other hides, In summary it can be said that the analysis of this very for example cow hide, took place, as no leather remains well preserved and interesting mass find of osteological have yet been found on the site. There are, however, finds material from Swedens first town has just begun. As this is of goat bone which suggest that goat hide was worked. The being written, the project has one further excavation season goat bones which can be identified, namely horn cores and left, with probably another one tonne of bone. After that is phalanges 1-3, suggest that goat hides were brought into finished, the first step is to carry out an archaeological the town. These bones have been interpreted elsewhere as phase and plot division of the material. Following that, cer­ remains of goat-hide tanning (Serjeantsson, 1989: 136). tain layers and parts of layers will be chosen for the The goat horn cores found at Birka have been most often archaeozoological analysis. It is not economically possible, removed from the rest of the body by cutting away the nor will there be time, to analyse the entire mass of the upper part of the frontal bone together with both the adher­ material in detail, so a number of tests will be made to cal­ ing horn cores. This is markedly different from the finds of culate the optimum size for the different samples from the cattle and sheep horn cores, which have been sawed away areas which will be studied. Each sample must be represen­ at the base of the horn. This was done so as to easily tative for the whole context from which it is taken. How remove the valuable horn from the bone. the tests will be carried out is as yet in the planning stage. Finally, it can be said that Birka, as the first urban set­ Thanks to the rough sorting of the whole material in the tlement in Sweden, experienced some of the more negative field, testing should be fairly easy. Furthermore, possible results of living in a closely built-up area. Besides prob­ "oddities", such as pathological specimens and unusual lems with rubbish disposai, the inhabitants of Birka were species have already been noted during the rough sorting of plagued by parasites, in the form of black rats and house each layer. These "oddities" or special occurences can be mice. During Hjalmar Stolpes excavations in the 1870s, easily located when needed with the help of the database bones from black rats were found, but these could not be and without needing to consider the sampling method. dated, so finds from Lund, in southern Sweden, dating to Sorne things which, among others, will be studied in the the eleventh century, have been counted as the eldest in analysis are species occurrence, species presence, and age Sweden (Bergquist, 1957). Black rats then appear in Sig­ and sex composition, to understand Viking Period animal tuna (Harding, 1992: 20f), and Eketorp III (Boessneck et management within and outside Birka. An understanding of al., 1979: 214f). Now, however, there is proof for a great what roll the capture of fish and wildfowl played in the sur­ number of black rats in Birka during the Viking Period, as vival of the town is very important for its archaeological early as the beginning of the ninth century. In total, there interpretation. With the help of bone measurements, it should are around 50 finds from the present excavations. The finds hopefully be possible to see from where domestic animais, have not yet been thoroughly examined, so as yet neither and possibly even fur-bearing animais, came. Unfortunately, an exact number of bones nor an exact dating can ben there is little well-preserved osteological material from the given. The oldest layers, however, do not seem to include surrounding area, but al! the archaeozoological analyses from

ANTHROPOZOOLOGICA. 1997, N° 25. 26 610

nearby sites will be used. Through studies of slaughter age of A very great amount of work remains to be done bath domestic animais, and fish and wildfowl, it may be pos­ with the analyses, but the results will be published in the sible to follow Birka's seasons, and with them the shifting excavation's report series Birka Studies, as soon as they patterns of food consumption and to answer the question of are ready. whether Birka was occupied the year round.

Bibliography

AMBROSIANI B., 1991.-Birka on the island BjorkiJ. Stockholm: Board of National Antiquities. AMBROSIANI B., 1992.- Excavations at Birka 1990-1994 : setting up the project. ln: B. Ambrosiani and H. Clarke eds., Birka Studies 1. Investigations in the Black Earth. Stockholm: RAÂ-SHMM, p. 83-86. AMBROSIANI B., ARRHENIUS B., DANIELSSON K., KYHLBERG O. and WERNER G., 1973.- Svartajordens hamnom­ râde. Arkeologisk undersèikning 1970-1971. Riksantikvariedmbetet Rapport C 1. Stockholm. AMBROSIANI B. and ERIKSSON B. G., 1991.- Birka - Vikingastaden volym 1. Helsingborg. AMBROSIANI B. and ERIKSSON B. G., 1994.- Birka - Vikingastaden volym 4. Stockholm. BERGQUIST H., 1957 .- Skeletal finds of Black rat from the Earl y Middle Ages. Archaeol. of Lund 1 : 98-103. BOESSNECK J., DRIESCH A. von den and STENBERGER L. eds., 1979.- Eketorp Befestigung und Siedlung auf Ôland/Schweden. Die Fauna. Stockholm. CLARKE H. and AMBROSIANI B., 1993. -Vikingastdder. Hèiganas. ERICSON P. G. P., 1987a.- Exploitation of seabirds in central Sweden during the late Iron age - conclusions drawn from the bird remains from Birka. In : G. Burenhult, A. Carlsson, À. Hyenstrand and T. Sjèivold eds., Theoretical approaches to arte­ facts, settlements and society. Studies in honour of Mats P. Malmer. BAR international series, 366 : 445-453. ERICSON P. G. P., l 987b.- Osteology of the Eider. Stockholm : The Museum of National Antiquities. Studies 5. ERICSON P. G. P., IREGREN E. and VRETEMARK M., 1988.- Animal exploitation at Birka. Fornvdnnen 83. Stockholm. HARDING B., 1991.- Vad benen berattar. ln: S. Tesch ed., Makt och mdnniskor i kungens Sigtuna Sigtunagrdvningen 1988- 1990. Sigtuna Museer. HARDING B., 1992.- Mat for dagen. Mathdllning och resursuttnyttjanden i Sigtuna under vikingatid och tidig medeltid. Upp­ sats i pâbyggnadskurs i Arkeologi. Stockholms universitet. (unpublished paper). JONSSON L., 1989.- Massfângst av sjofâgel och piilsdjursjakt. ln: Avstamp -for en ny Sigtunaforskning. 18forskare om Sig­ tuna. Kommitén for Sigtunaforskning. Sigtuna Museer. SERJEANTSSON D., 1989.- Animal remains and tanning tracte. ln: D. Serjeantsson and T. Waldron eds., Diet and crafts in towns. BAR British series, 199. STOLPE H., 1872.- Naturhistoriska och arkeologiska undersèikningar pâ Bjèirkèi i Miilaren 1. Ôfversigt af Kongl. Vet. Akad. Forhandlingar N° 1. Stockholm, p. 3-27. STOLPE H., 1873.- Naturhistoriska och arkeologiska undersèikningar pâ Bjèirkèi i Miilaren II. Ôfversigt af Kongl. Vet. Akad. Forhandlingar N° 5. Stockholm, p. 3-79. WIGH B., 1994.- Femtio tunnor grofre ben och 80 lâdor mindre ben. Populdr Arkeologi 1994, 1 : 34-36. WIGH B., 1995.-The animais bones from Birka 1991. ln: B. Ambrosiani and H. Clarke eds., Birka Studies 2. Excavations in the Black Earth 1990. Stockholm : RAÀ-SHMM, p. 88-89.

ANTHROPOZOOLOG!CA. 1997, N° 25, 26