More About White-striped and Tan-striped White-throated Sparrows

Last spring I posted an article containing many photos of the two colour “morphs” of the White-throated Sparow.

https://mileshearn.com/2019/05/03/white-striped-and-tan-striped-white-throated-sparrows-at-sunnybrook-park-may-3-2019/

Chris Earley’s book: Sparrows and Finches of the Great Lakes Region and Eastern North America (Firefly Books) contains some other fascinating details.

White-striped White-throated Sparrow
Tan-striped White-throated Sparrow

The White-throated Sparrow is unique because it has a mating pattern like no other bird. There are two colour morphs, white-striped and tan-striped, and males and females can be either morph. The unique part is the fact that a pair is usually made of one of each colour morph. This apparently occurs because white-striped males are aggressive compared to tan-striped males.

White-striped White-throated Sparrow
Tan-striped White-throated Sparrow

Also, white-striped females sing, whereas tan-striped females do not. Because the white-striped females sing, the white-striped males are aggressive towards them and thus mate only with tan-striped females. This leaves the less-aggressive tan-striped males to mate with the white-striped females.

White-striped White-throated Sparrow

Tan-striped White-throated Sparrow

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