Mountain Bluebird Feeding a Spider

A Perfect Circle

While checking bluebird nest boxes, we found these six mountain bluebird nestlings arranged in a perfect circle. Our local Audubon chapter has maintained and monitored this bluebird trail of 100 boxes for over 40 years.

A most substantial nestbox

I first noticed this female Mountain Bluebird sitting atop a piece of machinery with an insect in her mouth. Realizing she was feeding nestlings, I stopped to watch where she flew to, and saw her land on this railroad car coupler (which was on a scrapped flatcar, the nest was not at risk). I noticed the strands of grass in the coupler pocket and realized she had built her nest inside this mass of iron that weighs several hundred pounds, perhaps the most substantial ‘nestbox’ ever used by a bluebird.

Cornell Lab of Ornithology

Cornell Lab of Ornithology