I was reading a comic from XKCD which inspired me to ask this question: "well, where do they go when it rains?" I know that when it rains you usually don't see any birds flying through the sky.
I imagine they normally hide in trees or under other kinds of cover. But for migratory birds, I don't think it is possible to hiding under cover until the rain passes. There might not be any cover (trekking across seas) or it might stay rainy for a very long time (and therefore cold...).
I did some research, but the answers are conflicting. Some people say they do stay in trees, others say they AVOID trees (because trees can snap in a storm, plus if there's lightning then sitting in a tree will net fried birds). Then there's people saying that birds have a waterproof coating... but that's a bit contradictory with me not seeing birds when it rains.
So where do birds go when it rains?
I assume that different bird species and groups of birds will behave in different ways. I am interested in the case of migratory birds because they are likely to encounter different climates and have perhaps devised strategies to be safe. I would appreciate any well-referenced examples.