Age determination of amethyst?throated hummingbird (lampornis amethystinus) and white?eared hummingbird (hylocharis leucotis)

Abstract

Age is one the most important parameters in avian biology, since life-history strategies and population dynamics can be strongly influenced by age. Two characters are generally used to age hummingbirds (family Trochilidae): presence of maxillar striations and presence of beige to cinnamon fringes of dorsal feathers in the juvenile plumage. However, their applicability varies among species. For this reason, development and use of species specific criteria are highly recommended. Here, we describe age- and sex-dependent variation of the central rectrix shape in Amethyst-throated Hummingbird (Lampornis amethystinus) and White-eared Hummingbird (Hylocharis leucotis). Juvenile central rectrices are more pointed than definitive ones. This criterion meets three crucial properties of aging techniques: high discriminant ability (78% for Amethyst-throated Hummingbird and 99% for White-eared Hummingbird), wide temporal applicability, and ease of use with minimum experience.