Wow, heard a 'twack' on the plate glass of one of our windows or sliders in the other part of the house. Went to investigate and saw a wee goldfinch (or zebra?) twitching on the deck by a slider... I figured it was a goner. Couldn't bare to watch, so decided to let it die with dignity. Went back ten min later and it was standing in the same spot, & as it saw me approach, flew off to a nearby tree! They're made of tough stuff those wee feathery immigrants!