14 December 2021
White-throated sparrows are back for the winter. Here’s something to remember when you see them.
In the world of birds, the bright ones are male and the dull ones are female, right?
Not so for white-throated sparrows (Zonotrichia albicollis). In this species the bright white versus dull tan stripes are color morphs. The bright white-striped bird at top can be either male or female. The tan-striped below is also either sex.
The bird with bright yellow lores on the left could be female. The one with dull yellow could be male.
Amazingly the colors match up to personality traits regardless of sex.
White-striped birds are bold, aggressive, philandering and not particularly caring of their kids. They are not the best parents.
Tan-striped birds are gentle and very caring of their young. They’re the good parents among white-throated sparrows.
Since each bird can tell the other bird’s personality at a glance, you would think the gentle would mate with the gentle and the bold with the bold. But that’s not how they do it. They always mix it up.
White-striped (aggressive) males mate with tan-striped (care-giving) females and tan-striped (gentle) males mate with white-striped (philandering) females. Thus the color morphs and personalities persist.
You can’t tell a white-throated sparrow’s sex by its color but you pick out the good parents in the flock.
(photos from Wikimedia Commons; click on the captions to see the originals)