The impact of loggerhead shrikes on nesting birds in a sagebrush environment

Publication Type:

Journal Article

Authors:

Reynolds, Timothy D.

Source:

Auk, American Ornithologists' Union, Volume 96, Issue 4, p.798-800 (1979)

Call Number:

A79REY02IDUS

URL:

https://sora.unm.edu/node/23356

Keywords:

Lanius ludovicianus, Loggerhead Shrike

Abstract:

Although shrikes (Lanius spp.) are known to prey on small vertebrates, most authors consider birds to be a minor portion of their diet. Miller states that "birds at no time comprise more than 15% of the food." Craig, in his analysis of the predatory behavior of Loggerhead Shrikes (L. ludovicianus) in California, does not record a single instance of shrikes preying on other passerines. Analysis of the stomach contents of Loggerhead Shrikes indicates that birds account for only 1-8% of their annual food intake. Thus, in most situations the incidence of avian prey in a shrike's diet is relatively low. However, the impact of this limited predation on the avifauna of a particular area has not been assessed. This paper documents a situation in which Loggerhead Shrikes reduced the density of other passerines nesting in a sagebrush environment and effectively eliminated the production of young by the three species commonly nesting this habitat. Information presented here was gathered in conjunction with an investigation of avian populations on the Idaho National Engineering Laboratory (INEL) Site, approximately 48 km west of Idaho Falls, Idaho.