Thursday, March 7, 2013

Sexual Attraction in the Cedars: Female Cardinals Like Their Guys Bright

On February 22, I wondered aloud here about the brightest red Northern Cardinal I have ever seen. My family members had noticed the same thing; my wife even remarked that that Daddy Cardinal looked absolutely "neon." And I posted this picture, which doesn't quite do justice to how red he is, but gives some idea:

Well, I'm fairly sure it is a coincidence and not a reply to my blog, but the Cornell Lab of Ornithology has just blogged a possible answer in a post entitled, "Why So Red, Mr. Cardinal? NestWatch Explains."

The anomaly is why a male Cardinal singing from a high perch would not have shed his breeding plumes for a drab winter coat to avoid being an easy target for a hawk. The answer is (as it is so often in all species) -- sex. The males are bright and red "to advertise what good mates they'd make." Here is what Jason Martin and Robyn Bailey wrote that explains why some, like the one in my backyard, are so brilliantly red:

"According to the 'Birds of North America Online,' brighter males have higher reproductive success, hold better territories, and offer more parental care. The intensity of a cardinal's redness is related to what he's been eating. So when females see a bright male, it's a signal that he's healthy and holds a good territory. . . .

"By responding to redness as a sign of a promising mate, females have encouraged the evolution of bright coloring in males. This process is called sexual selection, and it's an everyday example of a process that can lead to extraordinary creatures like the birds-of-paradise. At the same time, the female's muted colors provide her (and her nest) with a protective camouflage that the male lacks. Furthermore, cardinals tend to have higher survival rates, possibly because they don't endure the stress of migration. The oldest recorded cardinals lived to be at least 15 and a half years old (one recorded in Pennsylvania and another in Virginia)."

Fascinating. All I can say is that my most reddish of all Redbirds must have been in great demand among the females out there in the cedars just beyond my feeder. If the quality of my birdseed helped make him become glowingly red, he owes me much thanks and some nice songs.

© Robert G. Holland  2013




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