Plumage Characteristics of Juvenile Black-Chinned Hummingbirds

Frank A. Baldridge
1983 The Condor  
Various criteria useful in separating adult female and juvenile Black-chinned Hummingbirds (Archilochus akxandrz] from similar species under favorable field conditions were discussed by Stiles (197 1). My purpose here is to describe juvenal plumage characteristics of A. akxundri that appear to be reliable indicators of sex, and to present a key for age and sex determination in this species. Plumages of Black-chinned Hummingbirds do not appear to have been studied in detail, as have those
more » ... s have those ofAnna' s Hummingbird (Culypte anna; Williamson 1956) and Selumhorus snecies (Aldrich 1956. Stiles 1972). Ridawav (1911) described juveniles as similar to adult females but with dorsal feathers terminally margined with buff, and throat coloration in juvenile females as immaculate, or with dusky spots and streaks smaller and less distinct than in juvenile males. Stiles (197 1) stated that the throat coloration of adult females is highly variable and that the throats of juvenile males average darker than adult females, while juvenile females are less heavily marked. Short and Phillips (1966) observed that females have acutely pointed inner primaries (3-7) but that the subterminal notch is less distinct than in males. Stiles (197 1) noted that the outer rectrices of adult females are bluntly pointed, and added that juveniles may lack this characteristic. Between August 1978 and September 198 1, I netted, banded, and released 2 12 Black-chinned Hummingbirds near Three Rivers, Tulare Co., California. The outer rectrices, fourth and fifth primaries (counting from inside), and representative feathers from the dorsum, throat, and primary coverts were obtained from 73 adult females and juveniles. These feathers were placed on notecards, along with band number, date, measurements, and other plumage notes. The degree of culmen corrugation (Or&Crespo 1972) was also noted. In analyzing these data, I separated adults from juveniles by the lack of culmen corrugations in the adults and by plumage characteristics (throat coloration of adult males
doi:10.2307/1367900 fatcat:cid5w7xxhvbgjmuw3uuwnstkia