April brings nest initiation.
Thanks for the info, BleuBijou. For some reason it had never occurred to me to follow the spring/summer rainfall. I'm curious as to what specific details you look for - do you just note where in rains the most/most consistently, where it hails, etc? I took a quick look at the 2015 precipitation history for the 4 areas I hunt most often and the places I found the most birds didn't seem to directly correlate to where it rained the most.
Then again, that probably just means I need to get better at finding birds