Yellow Bellied Sap Sucker

There was a yellow bellied sap sucker on the sidewalk on my way home from work yesterday, just lying there on the sidewalk. It was pretty sad for me, this beautiful looking bird dead with not a tree in sight for it to wrap on. I spread the wings out and it had white polka dots all over, and it had a red head and throat. It's breast was yellowey, hence their name I guess. How did it get here? It was on Milwaukee south of Grand, where that Pickens moving place is, a pretty urban spot. Was it overwhelmed by all the city around it? Poisin? Bird Flu? Who knows. I moved it to a spot under a bush. It was very light, I guess it would have to be to fly.