Sunday, July 30, 2017

late cardinal brood

Cardinal nestlings  Photo by Rex McDaniel

I'm two weeks late with this post. Rex McDaniel sent me these photos July 16. By now the cardinal nestlings in the photo have fledged. But nevertheless, it is still late in the season for northern cardinals to be in a family way. Raising young ones is not easy. That's an understatement. It's exhausting. Perhaps this may even be a third brood. It is July. 

My thinking is that cardinals are under extra pressure to reproduce because they are so flamboyant, especially the males. Female choice drives the bright colors in male birds. An unmated female cardinal will choose the brightest male available. Dull guys get left out, so as a whole, the species evolves towards brighter and brighter males. The dull guy genes fall by the wayside. 

The problem is that if you and I can see the flashy males, so can Cooper's hawks. So lots of bright males fall by the wayside as well, but their genes survive in the nestlings pictured above. Thus, in order to keep the population stable, three broods may be necessary. There would not be the same pressure on dull gray catbirds, another species that likes to hide in dense shrubbery and is about the same size.

If this is all true and it reasonable to believe it is, then does a mated pair of cardinals produce more male offspring than female to replace the high number of flashy males killed by predators because they have no natural camouflage?

Let's hope the hungry nestlings survived to fly away from this nest Rex found at Ijams Nature Center.

As always, Rex thank you for your attentive eye.

I have written about my friend Rex before. He is something of a flâneur. Click: strolling about.

Mom cardinal being protective of her young. 

Photo be Rex McDaniel.


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