THE TIMING AND RELIABILITY OF BILL CORRUGATIONS FOR AGEING HUMMINGBIRDS

Abstract

The extent of corrugation on the bill has proven to be a useful method in determining the age of hummingbirds (Ortiz-Crespo 1972; Stiles 1972; Baltosser 1987; Russell 1996). Nestlings and post-fledging juveniles have soft bills with deep corrugation covering 50% or more of the bill, whereas adults have harder bills with little or no corrugation.