Male birds of many species feed the female they are courting as part of the pair-bonding function. The purpose is to create and maintain the strong relationship needed for breeding, nesting, and raising young. Research also suggests that females who receive more food in this fashion lay larger clutches. Here, a pair of Northern Cardinals exchange a sunflower seed on a feeder in our backyard. It looked to me as I watched this for a couple of minutes that the female was the one passing the seed to the male. She has it in this photo, and the male eventually opened his bill to receive it.
