Yellow-headed blackbirds take the best nesting sites from red-winged blackbirds.
Yellow-headed blackbirds are much larger then their red-winged counterparts. Every spring, I notice that it's the red-winged blackbirds that show up first to stake out a territory for breeding. If they have chosen a nesting area that has some reeds and shallow water, it is unlikely that they will be evicted. However, when the larger yellow-headed blackbirds show up, all bets are off if they have chosen a large reed bed in deep water (up to 3 or 4 feet). Red-winged blackbirds are not super choosy about where they nest, as long as there are some reeds and standing water present. More successful males will want a better territory, one that one or more females will approve of. And they will defend it, against other males of the same species. Yellow-headed blackbirds are more picky, insisting on large reed beds in deep water. They also usually arrive later than the red-wings do, but that is not a problem for them. That's because they are bigger, both in si...