Bird Fossils

Most of the caves we have excavated in Southeast Alaska contain few, if any, bird remains. The one notable exception is On Your Knees Cave, where nearly ten thousand bird bones have been recovered. At least 30 bird species are represented from this site, dominated by sea birds such as auks, diving ducks, geese, cormorants, gulls, sand pipers, and loons (see table below). The most abundant birds are the common murre, parakeet auklet, tufted puffin, oldsquaw, common eider, and Canada goose. Remains of bald eagle, grouse, ptarmigan, and perching birds--representing the terrestrial fauna--are very rare in the cave fauna. Bird remains have been radiocarbon dated to before, during, and after the Last Glacial Maximum.

Class Aves                          Bird common names

Order Gaviiformes
  Family Gaviidae
    Gavia cf. pacifica              Pacific Loon
    Gavia cf. immer                 Common Loon

Order Pelicaniformes
  Family Phalacrocoracidae
    Phalacrocorax cf. auritus       Double-crested Cormorant
    Phalacrocorax cf. pelagicus     Pelagic Cormorant

Order Anseriformes
  Family Anatidae
    Chen caerulescens               Snow goose
    Branta cf. bernicla             Brant
    Branta canadensis               Canada goose
    Anas cf. platyrhynchos          Mallard
    Somateria mollissima            Common Eider
    Clangula hyemalis               Oldsquaw
    Melanitta perspicillata         Surf Scoter
    Melanitta fusca                 White-winged Scoter
    Bucephala cf. clangula          Common Goldeneye
    Bucephala albeola               Bufflehead

Order Falconiformes
  Family Accipitridae
    Haliaeetus leucocephalus        Bald eagle

Order Galliformes
  Family Phasianidae                Grouse & Ptarmigan

Order Charadriiformes
  Family Scolopacidae               Sandpipers

  Family Laridae
    Larus philadelphia              Bonaparte's Gull
    Larus cf. canus                 Mew Gull
    Larus cf. glaucesens            Glaucous-winged Gull

  Family Alcidae
    Uria aalge                      Common Murre
    Cepphus columba                 Pigeon Guillemot
    Brachyramphus marmoratus        Marbled Murrelet
    Cyclorrhynchus psittacula       Parakeet Auklet
    Cerorhinca monocerata           Rhinoceros Auklet
    cf. Ptychoramphus aleuticus     Cassin's Auklet
    cf. Aethia pusilla              Least Auklet
    Fratercula cirrhata             Tufted Puffin
    Fratercula sp. (large)          Large Puffin

Order Passeriformes                 Perching Birds

Why are bird remains so abundant at On Your Knees Cave? Arctic fox fossils occurs with the bird remains throughout Late Pleistocene sediments of On Your Knees Cave, and this fox is the likely accumulator since it is known to feed in sea bird rookeries. Many of the fossil bird bones have distinct bite marks from a fox-sized carnivore. This fox is absent from early Holocene deposits where bird remains are rare.

Some of the puffin bones at left are larger than the modern species. Many bird bones have distinct bite marks that match arctic fox (above).

The study of the bird remains from the caves of Southeast Alaska is still in the initial stages. Most of the species identified thus far still live in Southeast Alaska today, which is not surprising since most northern birds make long seasonal migrations. But the most abundant species in the cave fauna are not always the most abundant in the local waters around northern Prince of Wales Island. Two of the most common birds seen along the local coast, pigeon guillemot and rhinoceros auklet, are only moderately abundant in the cave. Puffins and diving ducks, which are abundant as fossils in the cave, are not seen in the local waters. Prince of Wales Island may have supported more sea bird rookeries and favored a somewhat different bird fauna before the development of the dense rainforest.

   
© 2002 by Timothy H. Heaton