Biology ETDs

Publication Date



Mobbing behavior of Mexican Jays (Aphelocoma ultrarmarina) and Scrub Jays (A. coerulescens) to a Great Horned Owl (Bubo virginianus) was studied in field and laboratory experiments during 1970 and 1971. In both series Mexican Jays had a stronger response to the owl in rate of calling, and a longer lasting response. Population distribution patterns and social compatibility of flock members are considered the most important differences in explaining the stronger response of Mexican Jays to the owl. Hand-reared naive Mexican and Scrub jays were also tested in the laboratory. At age 80 days Scrub Jays mobbed the owl. The naive Mexican Jays did not mob the owl until a later age. Their response was also unlearned. In the wild Mexican Jays probably learn to mob earlier as the young birds associate with adults. Differences in development are attributed to the opportunities of juvenile Mexican Jays to observe adult behavior, whereas Scrub Jays are separated from adults at an early age.



Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

J. David Ligon

Second Committee Member

James Smith Findley

Third Committee Member

Marvin LeRoy Riedesel

Fourth Committee Member

James Roman Gosz

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Biology Commons