White-throated Sparrow

• In practice it has four sexes: two genetic morphs, white-striped and tan-striped, that almost always pair with the opposite one, so that there are males and females of each morph and only four of the possible combinations occur in nature.
• That difference is encoded in a chromosomal inversion that behaves almost like a second sex chromosome, and each morph behaves differently: the white-striped birds are more aggressive and less attentive parents.
• Its song, a pure whistle of descending notes, is popularly transcribed in Canada as a call to the country itself and is one of the most recognisable sounds of the boreal forest.

Skeleton type

Vertebrate - internal bony skeleton (bird)

Habitat and environment

Boreal forest with dense understorey for breeding; hedgerows and gardens of the eastern US for wintering

Birth weight

Altricial: born blind, naked or with sparse down and entirely dependent

Size at birth

Altricial: born blind, naked or with sparse down and entirely dependent

Sexual maturity

12 months

Gestation / incubation

13 days

Litter / clutch size

4

Sources consulted: https://es.wikipedia.org/wiki/Zonotrichia_albicollis

Best time: From April to June in the boreal forests of Canada, when it sings without pause; in winter it moves down into the eastern United States.