The trunk and top branches of the Buckeye tree outside my (somewhat dirty) porch windows are brightly illuminated with the morning sun, making it the perfect place to bask in whatever heat the sunlight can provide on this chilly morning.
A chilly start…
Early in the morning, I’ve noticed a variety of birds and squirrels using the buckeye as a basking spot.
You don’t normally see White-breasted Nuthatches at rest in this posture (head up). Notice how the bird is plastered right up next to the trunk of the tree with its feathers maximally fluffed. Is it possible that the tree surface is actually “warm”? (well, probably warmer than the air…)
Red-bellied Woodpeckers apparently like the buckeye as a basking spot as well. This bird was sitting at rest, not foraging in this spot.
Even the much larger-bodied Gray Squirrels enjoy a little basking time on the trunk of the tree when the temperatures dip into the -20 F range. Belly and tail are plastered tightly to the trunk of the tree to soak up whatever warmth it can provide.
Usually we associate basking behavior with reptilian thermoregulation — sun-loving turtles and lizards, for example. Even crocodilians lie around in the sun letting its heat warm them while they digest their latest meal. But basking becomes important to birds and mammals as a means of economizing on the high metabolic expense of staying warm in extreme cold.
Here’s a bird that specializes in basking to warm up on cool mornings.