A method for estimating the ages of nestling Northern Harriers ( Circus cyaneus )

A model for predicting the age of nestling Northern Harriers (Circus cyaneus) is presented. The model requires measures of body mass, wing chord, and the presence or absence of tail feathers. Ninety-five percent confidence intervals of predicted ages are approximately ± 1.5 days, and the ages of chi...

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Bibliographic Details
Published in:Canadian Journal of Zoology
Main Authors: Saunders, Matthew B., Hansen, Gay L.
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1989
Subjects:
Online Access:http://dx.doi.org/10.1139/z89-259
http://www.nrcresearchpress.com/doi/pdf/10.1139/z89-259
Description
Summary:A model for predicting the age of nestling Northern Harriers (Circus cyaneus) is presented. The model requires measures of body mass, wing chord, and the presence or absence of tail feathers. Ninety-five percent confidence intervals of predicted ages are approximately ± 1.5 days, and the ages of chicks may be determined throughout the nestling period regardless of sex. This particular model was selected as it is highly accurate and employs variables that are easily obtained in the field.