SEX RATIOS AND BILL GROWTH IN NESTLING BLACK-CHINNED HUMMINGBIRDS

Abstract

Implicit in the analysis of sex ratios in wild bird populations is the assumption that equal numbers of males and females are conceived, hatched, and fledged. Sex ratios biased in favor of females have been reported for the Broad-tailed Hummingbird (Selasphorus platycercus) by Calder et al. (1983) and Calder (1990), and for the Ruby-throated Hummingbird (Archilochus colubris) by Mulvihill et al. (1992) and Bill Hilton (in litt.).