Many observers in our area have reported Rose-breasted Grosbeak (Pheucticus ludovicianus) sightings as these colorful birds make their way north toward their breeding grounds. We usually see some at our feeders, and this year was no exception.
In a post two years ago, I showed photographs of a Rose-breasted Grosbeak and a Cardinal (Cardinalis cardinalis) in a dispute over access to a bird feeder (http://www.gkochert.com/grosbeak-vs-cardinal). This pair of species must have some inherent animosity, because they were at it again this year. This time the fight was apparently about access to a suet feeder. However, I have never seen a Cardinal eating from any of our suet feeders. So why should it attempt to drive the Grosbeak away? At any rate, the Grosbeak won again, and got all the suet it wanted!