Density, habitat, and the mating system of the Western Sandpiper (Calidris mauri)
The hypothesis that intense predation, variable food availability, and increased social interactions in high density populations have been important factors promoting the evolution of polygynous and promiscuous mating systems in certain Calidridine sandpipers (Holmes and Pitelka, 1966) is examined in breeding populations of the Western Sandpiper (Calidris mauri) in subarctic Alaska.
Western Sandpipers breed in a habitat consisting of a complex mosaic of wet low-lying marshes and relatively well-drained, heath-covered tundra. They defend small territories and nest on the latter, while some feeding also occurs there. Most foods however are obtained off territory in the wet marshes and along the shores of lakes, rivers and sloughs.
Densities in the nesting areas ranged from 132–196 pairs/40 ha at the base of a low range of hills to 200–300/40 ha on hummocks surrounded completely by marsh. These densities, the highest reported for a Calidridine sandpiper, are relatively constant from year to year.
The mating system of the Western Sandpiper is monogamous, both sexes incubate and care for young. Correlated with a strong single pair-bond and stable populations is a strong tendency to return to the same site. Of sandpipers marked, an average of 57.6% of males and 48.8% of females returned in succeeding years, frequently to the same territory or its immediate vicinity. Of the pairs returning to the study area in subsequent years, 61.5% reunited.
The restriction of nesting activities to heath tundra is considered to be a result of the protection it provides for nests. With the separation of nesting and feeding areas and with relatively abundant food sources that are not significantly affected by weather, a large nesting area is not required, allowing high densities of Western Sandpipers to occupy the patches of heath-covered tundra. In this ecological context, the high intensity of social interactions has not resulted in the evolution of a nonmonogamous mating system. Indeed, the increased protection afforded offspring by the presence of both parents is probably the most important selective force promoting the evolution of the monogamous mating pattern in Western Sandpipers.
KeywordsMating System High Density Population Abundant Food Selective Force Ecological Context
Unable to display preview. Download preview PDF.
- Boyd, H.: Mortality and fertility of European Charadrii. Ibis 104, 368–387 (1962).Google Scholar
- Brandt, H.: Alaska bird trails, p. 1–464. Cleveland, Ohio: Bird Research Foundation 1943.Google Scholar
- Britton, M. E.: Vegetation of the arctic tundra. Arctic Biology-Oregon State College Biology Colloquium, 1957: 26–61 (1957).Google Scholar
- Brown, R. G. B.: The aggressive and distraction behaviour of the Western Sandpiper Erunetes mauri. Ibis 104, 1–12 (1962).Google Scholar
- Crook, J. H.: The evolution of social organization and visual communication in the weaverbirds (Ploceinae). Behaviour, Suppl. 10, 1–178 (1964).Google Scholar
- —: The adaptive significance of avian social organizations. Symp. Zool. Soc. Lond. 14, 181–218 (1965).Google Scholar
- —: Social behaviour in birds and mammals, p. 1–492. London-New York: Academic Press 1970.Google Scholar
- Drury, W. H., Jr.: The breeding biology of shorebirds on Bylot Island, Northwest Territories, Canada. Auk 78, 176–219 (1961)./Google Scholar
- Gabrielson, I. N., Lincoln, F. C.: The birds of Alaska, p. 1–922. Harrisburg, Pa.: Stackpole Co. 1959.Google Scholar
- Heldt, R.: Zur Brutbiologie des Alpenstrandläufers, Calidris alpina Schinzii. Corax 1 (17), 173–188 (1966).Google Scholar
- Hilden, O.: Zur Brutbiologie des Temminck-Strandläufers, Calidris temminickii (Leisl.). Ornis fenn. 42, 1–5 (1965).Google Scholar
- Holmes, R. T.: Breeding ecology and annual cycle adaptations of the red-backed sandpiper (Calidris alpina) in northern Alaska. Condor 68, 3–46 (1966a).Google Scholar
- —: Feeding ecology of the red-backed sandpiper (Calidris alpina) in arctic Alaska. Ecology 47, 32–45 (1966b).Google Scholar
- —: Differences in population density, territoriality, and food supply of Dunlin on arctic and subarctic tundra, p. 303–319. Symposium no 10 of British Ecological Society. Oxford-Edinburgh: Blackwell Publ. 1970.Google Scholar
- Holmes, R. T.: Ecological factors influencing the breeding season schedule of Western Sandpipers (Calidris mauri) in subarctic Alaska. Amer. midl. Nat. (in press, 1972).Google Scholar
- Holmes, R. T., Pitelka, F. A.: Ecology and evolution of sandpiper (Calidridinae) social systems. Abstr. XIV. Int. Ornithol. Congr., 70–71 (1966).Google Scholar
- Kozlova, E. V.: Fauna of U.S.S.R.—Charadriiformes, Limicolae], p. 1–432. Moscow: Akad. Nauk SSSR 1962.Google Scholar
- Lack, D.: Ecological adaptations for breeding in birds, p. 1–409. London: Methuen & Co. 1968.Google Scholar
- Orians, G. H.: The ecology of blackbird (Agelaius) social systems. Ecol. Monogr. 31, 285–312 (1961).Google Scholar
- —: On the evolution of mating systems in birds and mammals. Amer. Naturalist 103, 589–603 (1961).Google Scholar
- Parmelee, D. F.: Breeding behavior of the sanderling in the Canadian high arctic. The Living Bird 9, 97–146 (1970).Google Scholar
- —, Greiner, D. W., Graul W. D.: Summer schedule and breeding biology of the white-rumped sandpiper in the central Canadian arctic. Wilson Bull. 80, 5–29 (1968).Google Scholar
- Pitelka, F. A.: Numbers, breeding schedule, and territoriality in Pectoral Sandpipers of northern Alaska. Condor 61, 233–264 (1959).Google Scholar
- Soikkeli, M.: Breeding cycle and population dynamics in the dunlin (Calidris alpina). Ann. zool. fenn. 4, 158–198 (1967).Google Scholar
- —: Dispersal of dunlin Calidris alpina in relation to sites of birth and breeding. Ornis fenn. 47, 1–9 (1970).Google Scholar
- Southern, H. N., Lewis, W. A. S.: The breeding behavior of Temminck's stint. Brit. Birds 31, 314–321 (1938).Google Scholar
- Verner, J.: Evolution of polygamy in the long-billed marsh wren. Evolution 18, 252–261 (1964).Google Scholar
- —, Willson, M. F.: The influence of habitats on mating systems of North American passerine birds. Ecology 47, 143–147 (1966).Google Scholar