May Mating

This weekend I brought binos along on my morning walk and got a great look at the eagle’s nest. The female was in the nest with only her head visible. The male was perched on a branch about five feet away. The nest was massive. Based on the fact that a bald eagle is about 3 feet long from head to tail, I estimate that the nest was about 6 feet deep and 8 feet wide. Eagles often use nests over and over again, and I wonder if they built upon an existing nest.

Reading about eagles I discovered that they are monogamous for a lifetime. Other regional birds that mate for life include geese, swans, and some owls. Though they don’t all mate for life, it has been estimated that around 90% of birds are monogamous for at least a mating season. Recent studies suggest, however, that while most birds are socially monogamous (maintaining a paired relationship for child-rearing), they may not be sexually monogamous and often have what’s known as “extra-pair copulations”. Here is an interesting essay about that topic, as well as a book by the same author.

Bird spottings: Northern Harrier, Ruby-crowned Kinglet (!!), Mountain Bluebird, Killdeer, Yellow-rumped Warbler, Black-headed Grosbeak, and Hungarian (or Gray) Partridge (thanks to Dave’s eagle eye).