As I watched this chipping sparrow nest I noticed that one mouth was quite a bite bigger than the others. As it grew. It was just as I thought. A brown headed cowbird had laid one of her eggs in this nest. Mom & dad chipping sparrow were feeding like crazy to feed this baby along with 3 of their own. This is common practice with cowbirds. Who are twice the size of a chipping sparrow. I have seen song sparrows struggle to feed these gentle giant babies before. And like a true mom. They give it there all.