Anhingas in the south pond wing flapping.
When I look across the pond and see anhingas wing flapping, I think these fallen and now sunbleached tree limbs are a silver lining from Hurricane Irma. This is a favorite perch for anhingas.
The one on the left is a juvenile female (looking at the photo) and on the right, I believe it is an adult female. I used to think anhingas flapped because they did not have oiled wings. There is new information:
The structure of cormorant and Anhinga feathers decreases buoyancy and thus facilitates underwater pursuit of fishes. Hence their plumage is not water-repellent, but "wettable." It has been suggested that the function of the spread-wing postures in these birds is to dry the wings after wetting. Biologists once thought that deficient production of oils from the preen gland necessitate wing-drying behaviors. We now know, however, that the degree of waterproofing of feathers is primarily due to their microscopic structure, not to their being oiled. In addition to helping wing feathers to dry, other suggested functions for these postures include regulating body temperature ("thermoregulation"), realigning of feathers, forcing parasites into motion to ease their removal, and helping the perched bird to balance. (Standford University, Spread Wing Postures)
This is a female juvenile.
I think this is a female adult.
The next day, another wing drying session with yet another anhinga, this one an adult male:
And look at the size of their feet! That makes for skilled swimming.
Wildewood Springs. July 5, 2018.
