I am an amateur bird watcher and I’ve been seeing some birds in my back yard doing some strange things lately. Today I saw a brown thrasher (which is unusual in itself because I’ve never seen any around here) walk along the ground, stop, and then suddenly lie down with its wings and tail spread out. It looked dead, but a few minutes later it got up and flew away. I’ve also seen blue jays doing this. I’ve consulted my Guide to Bird Behavior, but it doesn’t mention sunbathing anywhere.
If that wasn’t it, then what were they doing?
Well, birds do sunbathe, but it is quite possible it was engaging in a behavior known as “anting.”
From here
Perhaps some of the strangest behaviour indulged in by birds is Anting. Anting occurs in two different forms and for the sake of this essay it does not always involve ants.
Most anting, however, does involve ants and over 250 different species of birds have been recorded displaying this behaviour at one time or another. Anting occurs either as active anting, in which the bird picks an ant up and applies it to its plumage, or passive anting. Normally, the ant during active anting will be stroked along the feathers, usually the flight feathers. Starlings (Sternus vulgaris) actively seek out Formicine ants which suggests that the ants’ ability to spray formic acid is an important consideration. It has been observed by many people that during anting the birds appear to get exceedingly excited. After the ant has been applied to the feathers it is either discarded or eaten. Other active anting birds are Babblers, Tanagers and Weavers.
Passive anting involves the bird finding an ants’ nest and lying down among the ants. This process often likened to bathing in ants is not as well studied as active anting. Birds which are passive anters include the European Jay, Crows and Waxbills.
Sounds like your bird may have been doing passive anting.
In my opinion, the most likely reason for this behavior is control of parasites such as feather lice.
