The Big Yard: Notes from a Pajama Birdwatcher

No Box of Chocolates for this Male Cassin’s Finch.

February 14, 2023

Valentine’s Day.  Male Cassin’s finches show their passion by blushing red.  “Red!” I hear Lola, the cabaret performer and drag queen in Kinky Boots, shout.  “Red! Is the color of sex!” 

In birds, feather coloration comes from two kinds of pigments: melanins and carotenoids.  Melanins give plumages their blacks and browns and grays, colors derived from deposited granules found in even fossil feathers dating back 160 million years.  Carotenoids produce the vivid oranges and scarlet reds—the colors love.  Since birds cannot synthesize these pigments, they must obtain them from their diet—from seeds and the fruits of pyracantha in the case of Cassin’s finches.

But today, something unusual among the dozen or more Cassin’s briskly and efficiently (dexterously?) hulling sunflower seeds with their thick, short bills.

A yellow male.

Maybe it was something he ate...or didn’t eat.

Male Cassin’s finches normally sport an attractive raspberry red crown and breast. What the drab, brown-patterned (camouflaged?) females find alluring as breeding season approaches.  But on rare occasions, a male may show yellow instead.  When the birds molt, their diet determines the colors of their new feathers.  Pale orange or yellow, rather than the usual studly red, according to experimental studies, means insufficient amounts of carotenoids from food. 

Like, too much junk food. 

Which tells me if you’re looking for a hot date this Valentine’s Day, stay away from the Cheez-Its and Little Debbie Cosmic Brownies. 

And please pass the kale chips.

A “Lonely” Yellow Male House Finch. The variable yellow-to-red plumage of male house finches is a classic example of a sexually selected indicator of quality in birds. Numerous field and laboratory studies point to female house finches choosing male house finches with the reddest plumage for the “associated reproductive benefits.”

Yellow Male Cassin’s Finch. In the Valentine’s Day dress code, red means “Already Booked.”  Yellow means “Failure in Love.”

A Male Cassin’s Finch “Wallflower”—ignored by the girls.

Happy Valentine’s Day!

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