Year: 2016
Type: article
Abstract: We analyzed variation in body mass, wing chord, and culmen in the Mexican Jay (Aphelocoma ultramarina) in relation to age, sex, month, and year using linear regression.All measurements were taken from color-banded individuals of known sex and age as part of a long-term study in the Chiricahua Mountains of Arizona.There was no significant variation among observers for mass, but there was for wing chord and culmen.Therefore, analyses of the latter measures were restricted to data of one observer.Males were heavier than females.Mean body mass declined from winter to summer.Mass increased over the first two years in each sex but not in older birds.Males had longer wings than females.Mean wing chord increased considerably from age 1 to 2 and increased significantly even after age 2. Males had significantly longer culmens than females in summer but not winter.A discriminant function separated yearling males from females in winter.The sexes in older birds could be discriminated in summer but not winter.
Authors: Jerram L. Brown, Nirmal Bhagabati
Language: English
Topic: Avian ecology and behavior
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W2495648444