Tuesday, January 16, 2018

Stripe-headed Sparrow

Stripe-headed Sparrows are found in western Mexico and western Central America. Mexican birds lack the gray breast band. Erika and I saw several in small trees and shrubs along a roadside near the Ensenada Lodge in western Costa Rica on 8 July. These birds are the only New World sparrows that breed cooperatively, where offspring help fledge their parents’ subsequent brood (Cornell Neotropical Birds). Evolutionary biologists wonder why the young would sacrifice their own reproductive potential in favor of their parents. Presumably time spent “baby sitting” improves the young’s chance of successful reproduction when the young get around to breeding.

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