Rock Sandpiper Calidris ptilocnemis Scientific name definitions

“One flock of about 20 birds was found at Cold Bay. . . . They were found as usual huddled closely together on a slippery, spray-washed rock, apparently oblivious of everything, and showing no particular interest in life.”

Osgood 1904 Osgood, W. H. (1904). A biological reconnaissance of the base of the Alaska Peninsula. North American Fauna 24:1–86. Close : Biological reconnaissance of the base of the Alaska Peninsula, North American Fauna

Osgood's anthropomorphic view of Rock Sandpipers in Alaska in mid- October is typical of many who have experienced this species at that time of year. Whether observed foraging on surf-splashed shores, huddled together during a blizzard awaiting low tide, or residing for months on substrates that regularly freeze, the Rock Sandpiper defies most conceptions about shorebirds. Not only does it winter farther north than any North American shorebird, but its pagophilic adaptations are unique among all shorebirds during the nonbreeding season.

This small but stocky sandpiper is truly a bird of Beringia, where at least 4 recognized subspecies have evolved within the region. Each has a distinct breeding plumage, but only one a unique winter dress. The total population of the species likely does not exceed 100,000 individuals; some subspecific populations are limited to several thousand birds and confined to a few islands in the central Bering Sea. The Rock Sandpiper favors low-elevation heath tundra for breeding, but it can also be found nesting at higher elevations throughout coastal mountains of western Alaska. It has a territorial, socially monogamous mating system and, in noninsular populations, often occupies habitat with Black-bellied Plovers (Pluvialis squatarola), Western Sandpipers (Calidris mauri), Dunlin (C.alpina), Ruddy Turnstones (Arenaria interpres), and Bar-tailed Godwits (Limosa lapponica). During the short breeding season, the Rock Sandpiper feeds primarily on adult and larval insects on the tundra; the remainder of the year, it resides on intertidal areas, where it subsists primarily on invertebrates, especially marine clams and snails. In autumn, it is not uncommon to find concentrations of tens of thousands of molting birds at single estuaries, especially along the coast of the Yukon Delta and Alaska Peninsula. The species' common name is somewhat of a misnomer, since almost the entire population of one subspecies and large segments of another have recently been found throughout the nonbreeding season on intertidal areas with soft substrates almost devoid of rocks. Migration strategies vary markedly among the various subspecies: one sedentary population engages in only local seasonal movements, whereas another embarks on annual round-trip flights of up to 9,000 kilometers between Russia and northern California.

For such a geographically restricted species, a fair-sized body of information exists, but it is weighted heavily toward subspecific characteristics, taxonomy, and distribution (Ridgway 1919 Ridgway, R. (1919). The birds of North and Middle America: A descriptive catalogue of the higher groups, genera, species, and subspecies of birds known to occur in North America, Part 8. U.S. National Museum Bulletin 50. Close , Conover 1944b Conover, H. B. (1944b). The North Pacific allies of the Purple Sandpiper. Field Mus. Nat. Hist. Zool. Ser. 29. Close , Gabrielson and Lincoln 1959 Gabrielson, I. N., and F. C. Lincoln (1959). The Birds of Alaska. Stackpole Company, Harrisburg, PA, USA. Close , Kozlova 1962b Kozlova, E. V. (1962b). Fauna S. S. S. R., Zool. Inst. Akad. Nauk S. S. S. R., nov. ser., no. 81. Ptitsy 2, no. 1, pt. 3. [Birds, Charadriiformes, Suborder Limicolae.]. Moscow-Leningrad: Akad Nauk S. S. S. R. Close , Portenko 1981 Portenko, L. A. (1981). Birds of the Chukchi Peninsula and Wrangel Island. Volume 1. Translation of Russian text by Amerind Publishing Company Pvt. Ltd., New Delhi, India. Close , Kessel 1989 Kessel, B. (1989). Birds of the Seward Peninsula, Alaska: Their Biogeography, Seasonality and Natural History. University of Alaska Press, Fairbanks, AK, USA. Close , Paulson 1993 Paulson, D. R. (1993). Shorebirds of the Pacific Northwest. University of Washington Press, Seattle, Washington, USA. Close ) and less toward aspects of reproductive ecology (Hanna 1921 Hanna, G. D. (1921). The Pribilof Sandpiper. Condor 23:50-57. Close ; Kondratiev 1982 Kondratiev, A. Y. (1982). Biology of waders on the tundra of northeast Asia (in Russian). Nauka, Moscow, Russia. Close ; Tomkovich Tomkovich 1985b Tomkovich, P. S. (1985b). Territoriality of some monogamous species of Calidridinae sandpipers. Paper read at Acta XVIII Cong. Intern. Ornithol, at Moscow. Close , Tomkovich 1994b Tomkovich, P. S. (1994b). Site fidelity and spatial structure of population in the Rock Sandpiper Calidris ptilocnemis and Dunlin Calidris alpina on Chukotsky Peninsula. Russ. J. Ornithol. 3:13-30. [In Russian]. Close ) and vocalizations (Miller et al. 1988a Miller, E. H., W. W. H. Gunn and B. N. Veprintsev. (1988a). Breeding vocalizations of Baird's Sandpiper Calidris bairdii and related species, with remarks on phylogeny and adaptation. Ornis Scandinavica 19:257-267. Close , Miller 1996a Miller, E. H. (1996a). Acoustic differentiation and speciation in shorebirds. In Ecology and Evolution of Acoustic Communication in Birds (D. E. Kroodsma and E. H. Miller, Editors). Cornell University Press, Ithaca, NY, USA. pp. 241–257. Close ). Autumn staging ecology has been addressed by Gill and Jorgensen (Gill and Jorgensen 1979 Gill, Jr., R. E. and P. D. Jorgensen. (1979). Preliminary assessment of the timing and migration of shorebirds along the northcentral Alaska Peninsula. Studies in Avian Biology 2:110-120. Close ) and Gill and Handel (Gill and Handel 1990 Gill, Jr., R. E. and C. M. Handel. (1990). The importance of subarctic intertidal habitats to shorebirds: a case study of the central Yukon-Kuskokwim delta, Alaska. Condor 92:709-725. Close ), winter ecology and habitat use by Gill (Gill 1997b Gill, Jr., R. E. (1997b). Rock Sandpipers wintering in Cook Inlet, Alaska. Field Notes 51:786-787. Close ) and Gill and Tibbitts (Gill and Tibbitts 1999 Gill, Jr, R. E., and T. L. Tibbitts (1999). Seasonal shorebird use of intertidal habitats in Cook Inlet, Alaska. In Final Rep: USDI, U.S. Geological Survey, Biological Resources Division, and OCS Study. Close ), foods and feeding ecology by Preble and McAtee (Preble and McAtee 1923a Preble, E. A., and W. L. McAtee (1923a). A biological survey of the Pribilof Islands, Alaska: I. Birds and Mammals. North American Fauna no. 46, U.S. Department of Agriculture, Biological Survey, Washington, DC, USA. Close ) and Smith (Smith 1952b Smith, W. G. (1952b). The food habits of a population of Black Turnstones, Aleutian Sandpipers, and Surf-birds wintering in southern British Columbia. B.A. thesis, Univ. of British Columbia, Victoria. Close ), regional population status by Buchanan (Buchanan 1999 Buchanan, J. B. (1999). Recent changes in the winter distribution and abundance of Rock Sandpipers in North America. Western Birds 30:193-199. Close ) and Gill and Tibbitts (Gill and Tibbitts 1999 Gill, Jr, R. E., and T. L. Tibbitts (1999). Seasonal shorebird use of intertidal habitats in Cook Inlet, Alaska. In Final Rep: USDI, U.S. Geological Survey, Biological Resources Division, and OCS Study. Close ), and conservation concerns by Gilland Handel (Gill and Handel 1981a Gill, Jr., R. E. and C. M. Handel. (1981a). "Shorebirds of the eastern Bering Sea." In The eastern Bering Sea shelf: oceanography and resources, edited by D. W. Hood and J. A. Calder, 719-738. Seattle: Univ. of Washington Press. Close ), Gill et al. (Gill et al. 1994 Gill, Jr., R. E., R. Butler, P. S. Tomkovich, T. Mundkur and C. M. Handel. (1994). Conservation of North Pacific shorebirds. Transactions of the North American Wildlife and Natural Resources Conference 59:63-78. Close ), Gill (Gill 1996 Gill, Jr., R. E. (1996). "Alaska shorebirds: status and conservation measures at a terminus of the East Asian-Australasian flyway." In Conservation of migratory waterbirds and their wetland habitats in the East Asian-Australasian Flyway., edited by D. R. Wells and T. Mundkur, 21-42. Tokyo: Wetlands Int.-Asia Pacific, Kuala Lumpur, Publ. no. 116, and Int. Waterfowl Wetlands Res. Bur.-Japan Comm. Close ), and Buchanan (Buchanan 1999 Buchanan, J. B. (1999). Recent changes in the winter distribution and abundance of Rock Sandpipers in North America. Western Birds 30:193-199. Close ). Data gaps include much-needed information on population demographics, status and trends of subspecific populations, and movements of subspecific populations during the nonbreeding season.