Observations on Food Habits of Incubating Female Blue Grouse

Abstract

Few data are available concerning foods eaten by incubating birds. We know of only two such references to tetraonids in North America, each of which deals with observations on use of feeding sites by two birds only (Schladweiler, J. Wildl. Mgmt. 32:426428, 1968; Pendergast and Boag, J. Wildl. Mgmt. 34: 605-611, 1970). Our data too are limited, consisting of crop samples from 19 incubating female Blue Grouse (Dendragapus obscurus) collected on Vancouver Island, British Columbia, in the summer of 1962. Nevertheless, these birds were taken from two structurally different habitats and give some insight into the range of foods acceptable to incubating Blue Grouse over a relatively short distance, the study areas being only 30 airline miles apart. The areas from which our birds were collected are Comox Burn (10 birds), near Courtenay, and Middle Quinsam (9 birds), near Campbell River. Comox Burn was swept by wildfire in September 1961; thus, birds here were collected from an area in the first growing season following burning. New plant growth was mainly from seeds or rootstocks that survived the fire. In contrast, about one-third of Middle Quinsam was burned by wildfire in 1938 and the other two-thirds in 1951. Succession was well advanced by 1962 and structure of the habitat and availability of plants were very different than at Comox Burn (Zwickel and Bendell, Proc. XV Int. Ornithol. Congr., In Press, 1972).