Bristled

There was a line-up for the suet today; at one point I counted 18 birds on the nearby branches.  All different varieties of birds, big and small, waited in the surrounding trees, jockeying for position, while the little red squirrel took his time chowing down.  A few spats took place during the long wait, which lead to feathers flying and heads bristling.  But eventually everyone took a turn and surprisingly there is still some suet left in the end.  

I thought this male hairy woodpecker had that look of irritation and impatience one gets while waiting in a long line.