Willow Ptarmigan Lagopus lagopus Scientific name definitions

The largest and most numerous of North America's 3 species of ptarmigan, the Willow Ptarmigan is a characteristic feature of arctic, subarctic, and subalpine tundra. This species has developed a variety of behavioral and physiological adaptations for living in extreme northern environments, where temperatures and light levels vary dramatically and predators abound: feathered tarsi that function as snowshoes, use of snow burrows for shelter, and a complex pattern of molting that results in cryptic plumage year-round. Both the Willow Ptarmigan and its congener the Rock Ptarmigan (Lagopus muta), have Holarctic distributions; they are the only 2 grouse species with a circumpolar distribution.

Willow Ptarmigan are usually monogamous, but 5–9% of males may be polygynous. Unusual for grouse, pairs remain together from the beginning of the breeding season until their chicks are independent. This is the only grouse in which the male is regularly involved in parental care.

Field studies of the conspecific Red Grouse (Lagopus lagopus scoticus) in Great Britain and Willow Grouse (L. l. lagopus) in continental Europe conducted during the past century have yielded comprehensive information on the life history and behavior of the species, in addition to substantive contributions to wildlife population dynamics and life history theory (Jenkins et al. 1963 Jenkins, D., A. Watson and G. R. Miller. (1963). Population studies on Red Grouse, Lagopus lagopus scoticus (Lath.) in north-east Scotland. Journal of Animal Ecology 32:317-376. Close , Watson and Jenkins 1964 Watson, A. and D. Jenkins. (1964). Notes on the behaviour of the Red Grouse. British Birds 57:137-170. Close , Cramp and Simmons 1980a Cramp, S., and K. E. L. Simmons, Editors (1980). The Birds of the Western Palearctic. Volume 2. Hawks to Bustards. Oxford University Press, Oxford, UK. Close , Pedersen et al. 1983 Pedersen, H. C., J. B. Steen and R. Andersen. (1983). Social organization and territorial behaviour in a Willow Ptarmigan population. Ornis Scandinavica 14:263-272. Close ). Unlike its wily European counterpart, the Willow Ptarmigan in most of North America (with the exception of Newfoundland) is relatively tame and may be observed and captured readily. Population dynamics studies began more than 30 yr ago in Newfoundland (Peters 1963b Peters, S. S. (1963b). Population dynamics of the Newfoundland Willow Ptarmigan on the Avalon Peninsula. Ph.D. thesis, Cornell Univ., Ithaca, NY. Close , Mercer 1967b Mercer, W. E. (1967b). Ecology of an island population of Newfoundland Willow Ptarmigan. St John's: Newfoundland and Labrador Wildl. Serv. Close , Bergerud Bergerud 1970a Bergerud, A. T. (1970a). Population dynamics of the Willow Ptarmigan Lagopus lagopus alleni L. in Newfoundland 1955-1965. Oikos 21:299-325. Close , Bergerud 1970b Bergerud, A. T. (1970b). Vulnerability of Willow Ptarmigan to hunting. Journal of Wildlife Management 34:282-285. Close ) and in Alaska (Weeden Weeden 1965c Weeden, R. B. (1965c). Grouse and ptarmigan in Alaska: their ecology and management. Alaska Dep. Fish Game. Close , Weeden 1967 Weeden, R. B. (1967). Seasonal and geographic variation in the foods of adult White-tailed Ptarmigan. Condor 69:303-309. Close ). Studies on bioenergetics, nutrition, and biogeographic variation were conducted in Alaska (West and Meng West and Meng 1966 West, G. C. and M. S. Meng. (1966). Nutrition of Willow Ptarmigan in northern Alaska. Auk 83:603-615. Close , West and Meng 1968 West, G. C. and M. S. Meng. (1968). Seasonal changes in body weight and fat and the relation of fatty acid composition to diet in the Willow Ptarmigan. Wilson Bulletin 80:426-441. Close , Irving et al. Irving et al. 1967a Irving, L., G. C. West and L. J. Peyton. (1967a). Winter feeding program of Alaska Willow Ptarmigan shown by crop contents. Condor 69:69-77. Close , Irving et al. 1967b Irving, L., G. C. West, L. J. Peyton and S. Paneak. (1967b). Migration of Willow Ptarmigan in arctic Alaska. Arctic 20:77-85. Close , West West et al. 1968c West, G. C., S. Savage, L. Irving and L. J. Peyton. (1968c). Morphological homogeneity of a population of Alaska Willow Ptarmigan. Condor 70:340-347. Close , West 1972 West, G. C. (1972). Seasonal differences in resting metabolic rate of Alaskan ptarmigan. Comparative Biochemistry and Physiology 42A:867-876. Close ). Since 1980, multiyear studies of behavior, mating systems, reproductive ecology, and fitness of individuals have been conducted in northwestern British Columbia (Hannon Hannon 1983 Hannon, S. J. (1983). Spacing and breeding density of Willow Ptarmigan in response to an experimental alteration of sex ratio. Journal of Animal Ecology 52:807-820. Close , Hannon and Smith 1984 Hannon, S. J. and J. N. M. Smith. (1984). Factors influencing age-related reproductive success in the Willow Ptarmigan. Auk 101:848-854. Close , Martin and Hannon 1987 Martin, K. and S. J. Hannon. (1987). Natal philopatry and recruitment of Willow Ptarmigan in north central and northwestern Canada. Oecologia 71:518-524. Close , Mossop 1988 Mossop, D. H. (1988). "Winter survival and spring breeding strategies of Willow Ptarmigan." In Adaptive strategies and population ecology of northern grouse., edited by A. T. Bergerud and M. W. Gratson, 330-378. Minneapolis: Univ. of Minnesota Press. Close , Hannon and Martin Hannon and Martin 1992 Hannon, S. J. and K. Martin. (1992). Monogamy in Willow Ptarmigan: is male vigilance important for reproductive success and survival of females? Animal Behaviour 43:747-757. Close , Hannon and Martin 1996 Hannon, S. J. and K. Martin. (1996). "Mate fidelity and divorce in ptarmigan: polygyny avoidance on the tundra." In Partnerships in birds: the study of monogamy., edited by J. M. Black, 192-210. Oxford: Oxford Univ. Press. Close ); near Hudson Bay, Manitoba (Martin Martin 1984b Martin, K. (1984b). Reproductive defense priorities of male Willow Ptarmigan (Lagopus lagopus): enhancing mate survival or extending paternity options? Behavioral Ecology and Sociobiology 6:57-63. Close , Martin 1991a Martin, K. (1991a). Experimental evaluation of age, body size and experience in determining territory acquisition in Willow Ptarmigan. Canadian Journal of Zoology 69:1834-1841. Close , Martin and Cooke 1987 Martin, K. and F. Cooke. (1987). Bi-parental care in Willow Ptarmigan: a luxury? Animal Behaviour 35:369-379. Close , Martin et al. 1989 Martin, K., S. J. Hannon and R. F. Rockwell. (1989). Clutch size variation and patterns of attrition in fecundity of Willow Ptarmigan. Ecology 70:1788-1799. Close ); and in Ontario (Thomas 1984b Thomas, V. G. (1984b). Winter diet and intestinal proportions of Rock and Willow Ptarmigan and Sharp-tailed Grouse in Ontario. Canadian Journal of Zoology 62:2258-2263. Close ). Much remains to be learned, however, about migration patterns, scale of dispersal, and life history differences among subspecies.