Preening Tree Swallow

Here's a female Tree Swallow taking a little time to do some feather preening. (I'm pretty confident the gray coloring instead of a shiny blue indicates this is the more modestly colored female.)

While bat wings are mostly a thin membrane of skin, much of the functional part of a bird's wing consists of its feathers. Feathers are also important for warmth and (especially among waterfowl) waterproofing. Unfortunately for birds, their feathers become dirty, wet, infested with parasites, and the feather barbs become separated, all of which can reduce their effectiveness. Thus it's important for birds to preen themselves to keep their feathers working properly. Preening is done quite a bit by the conscientious bird.

Sometimes (as in this picture) a preening bird will essentially "nibble" on a feather to dislodge dirt/parasites and to smooth it out. In other cases they'll pass their bill over each (reachable) feather to accomplish the same result. In many species of bird, including Tree Swallows, they'll also "oil" their feathers from secretions from what's called a preen gland located near the end of their tail.

Preening head feathers needs to be done differently since they can't be reached with their bill. Many birds use their feet or wings to do the best they can to preen their head feathers, though some birds will get help from a trusted friend bird to get their head feathers preened.

May 25, 2023 at Duke Farms
Photo 292816262, (c) jpviolette, some rights reserved (CC BY-NC)