Spizella pusilla (Wilson & A 1810)

Spizella pusilla (Wilson)

Kondla and Pinel (1971) have recorded the field sparrow (subspecies S. pusilla menaced) as a victim of the brown-headed cowbird (M. ater artemisiae) in southern Alberta, the northwesternmost area yet reported for this victim. Actually Alberta is just north of the range of the host as given in the 1957 A. O. U. Check-List (pp. 616–617). Either the sparrow is extending its range or the paucity of local observers has limited our knowledge of its occurrence in southern Alberta before now. While the field sparrow is a frequent victim of the cowbird, with over 125 records of parasitism (Friedmann, 1963:164–165), there were only 2 earlier records for the race S. pusilla arenacea, both from South Dakota.

Mr. F. F. Nyc, Jr. has informed us that he found a parasitized nest of the field sparrow in Caldwell County, Texas. The brown-headed cowbird in that area is of the race M. ater obscurus, a subspecies of the parasite not previously noted as affecting this sparrow.

Since the 1963 compilation some 66 additional instances of parasitism on the nominate race of the sparrow have come to our notice. In the collections of the Western Foundation there are 122 sets of eggs of the field sparrow, 9 of which (7.4 percent) were parasitized. In Ontario, of 179 nests reported to the files at Toronto, 36 (20.1 percent) were parasitized.

WHITE-CROWNED SPARROW