john@nmt.edu (John Shipman) (12/15/90)
An earlier posting asked about the feeding habits of shrikes, especially allegations that shrikes would take on prey larger than themselves, and that they would scavenge carrion. I finally had time to get out my references, so here are some relevant quotations from A. C. Bent's ``Life Histories of North American Wagtails, Shrikes, Vireos, and Their Allies:'' ...[the Northern Shrike] has been known to kill: chickadee, snow bunting, downy woodpecker, vireo, kinglet, field sparrow, goldfinch, siskin, myrtle warbler, mourning dove, cardinal, longspur and horned lark.... ^^^^^^^^^^^^^ Carrion is sometimes eaten. Prof. F. E. L. Beal, while at Ames, Iowa, in January, 1880, saw a butcherbird fly over the brown frozen prairie to a carcass of a cow, where it lit on one of the ribs and greedily tore off shreds of the flesh. [p. 117] The shrike's usual method is to rise above its victim and dive down upon it, felling it to the ground with a stunning blow from its powerful beak, which often proves fatal by breaking the little bird's neck or its back. The shrike follows it to the ground immediately and, if necessary, kills the bird with a blow at the base of the skull or by biting through the vertebrae of the neck. [p. 120] The prey spectrum of the Loggerhead Shrike runs smaller than that of the Northern, but Bent quotes one case of predation on a 16.5" rough-scaled green snake, _Opheodrys_aestivus_: ``I know that the shrike was handling much more than its own weight.'' [p. 142] Shrikes are nasty little customers by all accounts, an their habit of impaling their food on thorns and ripping pieces out of it gave rise to their nickname of ``butcherbird.'' Interested parties may wish to try their local library for copies of Bent's ``Life Histories'' series, always a fascinating reference. -- John Shipman/Computer Science Department/New Mexico Tech/Socorro, NM 87801 (505)835-5301; john@jupiter.nmt.edu