摘要:

Observations of freshwater drinking in Eiders feeding primarily on mussels led us to hypothesize that the highly saline sea water enclosed in mussels could cause salt‐related dehydration problems in the ducks, since they consume entire mussels. The proportion of sea water increases with increasing mussel size. Smaller duck species are more sensitive to the higher salt content of larger mussels than are larger ducks; however, salt stress may be avoided by feeding in habitats with lower salinity, by feeding on less salty food items, by utilizing smaller mussels, by drinking fresh water, or by employing low energy foraging techniques. A possible evolutionary strategy for solving the salt problem might be to increase body mass, enabling ducks to utilize larger mussels without passing an upper salt consumption limit. At the same time, foraging on larger mussels is more economical. Although large size facilitates the utilization of brackish and marine environments, it may be selected against in ducks breeding in fresh water, where fish competition may reduce optimal food item size. In conclusion, salinity is an important habitat barrier in both breeding and overwintering diving ducks, but there are various ways of crossing this barrier. To understand better how ducks utilize their habitats, however, it is necessary to measure habitat salinity levels and the size of both ducks and their preferred and less‐preferred food ty

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1988.tb00960.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Hooded Crows Corvus cornix, Great Black‐backed GullsLarus marinusand Herring Gulls L. argentatus were the main nest predators in an Eider population in southwest Sweden. The clutch sizes of Eider nests within gull colonies did not differ from those outside gull colonies. The proportion of Eider nests destroyed by predators was significantly lower within than outside gull colonies, especially on islands with Lesser Black‐backed Gulls L. fuscus. Although the difference was not significant, the survival time of simulated Eider nests was higher within than outside gull colonies. On Eider islands with gull colonies, foraying crows spent more time within the colony area than expected by chance. However, crows apparently avoided an area around each gull nest, and we suggest that the colonies, to some extent, protected Eider nests against predation. The density of Eider nests was higher on gull islands than on gull‐ free islands, and higher within than outside the gull colonies. However, the association with gulls was weak compared to that displayed by some other wate

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1988.tb00961.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The peculiar crossover origin of the cervical Musculus splenius capitis was studied in 32 hummingbird species. In this avian family the cruciform neck muscle exhibits extreme intra‐ and interspecific variations independent of age, thus taxa clustering for phylogenetical purposes according to the muscle's distinctive features is impossible. It is argued that the Musculus splenius capitis serves primarily to control precisely fast sideward head movements of hummingbirds while they are preying on insect

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1988.tb00962.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Book reviewed in this article:Brown, B. T., Carotheks, S. W.,&Johnson, R. R. 1987. Grand Canyon Birds.Brown, D. E. 1985. Arizona Wetlands and Waterfowl.Cheng, T.‐H. (Zheng, Z.). 1986. Birds of the World: Latin, Chinese, and English.Feige, K.‐D. 1986. Der Pirol. Pp. 216, 92 figures (many black‐and‐white photographs), 24 tables. Die Neue Brehm‐Biicherei 578. Wittenberg Lutherstadt: A. Ziemsen Verlag.Fraga, R.&Narosky, S. 1985. Nidificacion de las Aves Argentinas (Formicariidae a Cinclidae).GWINNER, E. 1986. Circannual Rhythms: Endogenous Annual Clocks in the Organization of Seasonal Processes.Harwood, M. (ed.) 1985. Proceedings of Hawk Migration Conference IV. Pp. 393, various tables and figures. Hawk Migration Association of North America.Hilty, S. L.&Brown, W. L. 1986. A Guide to the Birds of Colombia.Ito, J., Brown, L.&Kikkawa, J. 1987. Animal Societies: Theories and Facts.Kavanau, J. L. 1987. Lovebirds, Cockatiels, Budgerigars: Behavior and Evolution.Knystautas, A. J. V.&Sibnev, J. B. 1987. Die Vogelwelt Ussuriens.Lane, B. A. 1987. Shorebirds in Australia.MEDMARAVIS and MonbailliuX. (eds). 1986. Mediterranean Marine Avifauna: Population Studies and Conservation.Narosky, S., Fraga, R.&de laPe∼a, M. 1983. Nidificacion de las Aves Argentinas (Dendrocolaptidae y Furnariidae)Fraga, R.&Narosky, S. 1985. Nidificacion de las Aves Argentinas (Formicariidae a Cinclidae)Noval, A. 1986. Guia de las Aves de Asturias.O'Connor, R. J.&Shrubb, M. 1986. Farming and Birds.Paz, U. 1986. The Plants and Animals of the Land of Israel.Perrins, C. M. 1987. Collins New Generation Guide to the Birds of Britain and Europe.Perry, K. 1987. The Irish Dipper.Ridley, M. (ed.) 1986. Proceedings of the Third International Symposium on Pheasants in Asia, Chiang Mai, Thailand. 26–28 January 1986.Rubenstein, D. I.&Wrangham, R. W. (eds) 1986. Ecological Aspects of Social Evolution: Birds and Mammals.Skutch, A. F. 1987. Helpers at Birds' Nests: a Worldwide Survey of Cooperative Breeding and Related Behavior.Solomonov, N. G. (ed.) 1987. Red Data Book of the Yakut ASSR: Rare and Endangered Species of Animals. (Russian.)Ulrich, T. J. 1984. Birds of the Northern Rockies.Wink, M. 1987. Die Vogel des Rheinlandes, III. Atlas zur Brutvog

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1988.tb00964.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Andreev, A. V.&Kretchmar, A. V. (eds) 1986. Experimental Methods and Results of their Application in Northern Birds Studies.Blondel, J.&Frochot, B. (eds). 1987. Bird Census and Atlas Studies.Chatfield, J. 1987. F. W. Frohawk, his Life and Work.Davidson, I. H. 1986. Birds of Lapalala Wilderness, Waterberg, Transvaal, Southern Birds 13.Dendaletche, C. (ed.) 1987. Oiseaux des Pyrenees (1).Eai.es, T. 1986. Countryman's Memoirs.Edwards, E. P. 1986. A Coded Workbook of the Birds of the World Vol 2. Passerines.Eriksson, M. O. G. (ed.) 1987. Proceedings of the Fifth Nordic Ornithological Congress, 1985, Onsala, Sweden, 5–9 August, 1985.Freethy, R. 1987. Auks: An Ornithologist's Guide.Flegc, J. 1987. The Blue Tit.Ilyichev, V. D. (ed.) 1986. Contemporary Problems of Ornithology. Proc. All‐Union Orn. Soc. 1. (Russian.)Instituto deInvestigaçaoCientíficaTropical. 1986. Anuario de Actividades 1986.Kinzelbach, R.&Kasparek, M. (eds) 1986. Zoology in the Middle East.Mees, G. F. 1986. A List of the Birds Recorded from Bangka Island, Indonesia.Muller, Y. 1985. L'Avifaune Forestiere Nicheuse Des Vosges du Nord sa Place dans le Contexte Medio‐europeen.NationalGeographicSociety. 1987. Field Guide to the Birds of North America.Roche, J. 1986. Les Oiseaux Nicheurs des Cours d'Eau du Bassin de la Saône. Étude Ecologique des Peuplements le long du Gradient Amont‐aval.Snow, D. W. 1987. The Blackbird.Sokolov, V. E.&Dobrvnina, I. N. (eds) 1987. Ringing and Marking of Animals in the Years 1983–1984.Sultanov, F. F. (ed.) 1979. Proc. Acad. Sci. Turkmen. SSR Ser. Biol. Sci. (4).Syroechkovskiy, E. V. (ed.) 1987. Ecology and Migrations of Swans in the USSR. (Russian.)Taylor, M. 1987. The Birds of Sheringham.Tomkies, M. 1987. On Wing and Wild Water.Weaver, P. 1987. The Lapwing.Zwinger, A. 1986. John Xantus, the Fort Tejon Lett

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1988.tb00965.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1988.tb00966.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY