Blackbirds and Robins are a couple of common garden species you might see exhibiting this behaviour. Many other birds around the world also do so.
They lie down in the sun, spread themselves out and ruffle their feathers, and expose their skin to the heat of the sun.
It is thought this has two effects, it softens preening oil and helps it spread on to the feathers, it also it causes tiny ticks to move and they become easier to find and remove, during preening.
Now I knew this, but here is were it gets more interesting. Just checking these facts, led me to quite an amazing discovery.
Apparently, some of these tiny ticks that live on the birds, survive by eating the feathers, but even more unusual is that some species of ticks are only ever found one one particular species of bird !!
Fascinating... I have a number of blackbirds (mostly red-winged ones) and robins (the big North American ones)around here, but I've never observe this behaviour. Now I'll be keeping my eyes open for it.
