Thursday, March 2, 2017

Animals in their habitat: Desert Sparrows

Animals in their habitat: Black-throated Sparrows are character birds of our SW desert. All during spring their metallic song can be heard around our house in the bajada of the Tucson Mountains, but I've also found a nest in the grasslands around Cochise Stronghold on a friend's property. True to style, even that nest was hidden in a cholla cactus. But one of the five eggs in it was bigger and whiter than the other four. A cow bird had smuggled in a little parasitic guest. Th...e nest was very well protected with spiny jumping cholla branches, but my friend, being an entomologist in search of dung beetles, was armed with very long forceps. So he removed the cow bird egg. I was ambiguous about this interference, but he did the math: minus one cowbird means plus 4 sparrows, because the early hatching CB chick would have pushed the sparrow eggs out of the nest.

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