Buteo lagopus - Sexing autumn

Rough-legged Buzzard

SEXING:

3cy+: Most birds are possible to sex safely according to the below (based largely on Forsman [1999] and Forsman [in lit.]) but note that any ambiguous individual should be left unsexed.

2cy: In 2cy birds the situation is more difficult; the few birds which show clear male characters should be sexed as such, but since many males have yet to develop these traits, most birds should be left unsexed.

1cy: Not possible to sex according to plumage.

Note 1: Each single character is subject to extensive variation, and sexing should be based on an overall assessment. 

Note 2: There are additional sex-related characters, but those presented below are the ones we believe are the most reliable when working with hand-held birds. 

Male, 3cy+, October. Most males show a rather solid dark throat and upper breast. [9119055]

Male, 3cy+, October. A few male show a paler throat and upper breast. However, note the rather coarse and blotchy pattern created by large dark feather centres. [9119064]

Female, 3cy+, September. Throat and upper breast are generally paler, often showing a dark streaked pattern. [9119081]

Female, 3cy+, October, showing variation. Note that some females may be darker than the ones shown here, and may be confusingly similar to males. [9119084]

Male, 3cy+, October. Males generally show a slightly darker underwing with coarser dark barring to underwing-c, SS and inner PP. [9119062]

Male, 3cy+, October, showing variation. [9119064]

Female, 3cy+, September. Conversely, females generally show a slightly paler underwing with finer and more sparse dark barring to underwing-c, SS and inner PP. [9119081]

Female, 3cy+, October, showing variation. [9119084]

Male, 3cy+, October. Males show at least one (often two to four) additional narrow dark bars inside the broad subterminal bar. [9119059]

Male, 2cy+, October, showing variation. [9119064]

Female, 3cy+, September. Most females show only a broad dark subterminal bar to RR, but birds with one additional dark bar are not uncommon (exceptionally, two narrow dark bars may be present). [9119081]

Female, 3cy+, November. Many females show large diffuse dark patterns, making the bars less distinct. [9119071]

More Buteo lagopus:

Ageing autumn
Moult

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