House Sparrows Put On Their Winter Coats

House sparrow in British Columbia, Canada (photo from Wikimedia Commons)

Birds that eat insects leave Pennsylvania for the winter but the omnivores, like this house sparrow, stay behind.  Food won’t be a problem but it’s going to get cold so the house sparrows get ready in advance.

A study by Lowther and Cink in 1992 found that house sparrows (Passer domesticus) prepare for winter by molting into heavier plumage. Plumage weight increased 70% between August and September alone.  Summer weight is 0.9 grams; winter weight is 1.5 grams.

In September the house sparrows put on their winter coats.

(photo from Wikimedia Commons; click on the caption to see the original. 
This article was inspired by page 153 of Ornithology by Frank B. Gill, 3rd edition.) )

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