It’s interesting to me that Red-winged Blackbirds are so cordial toward their own species and other species during migration. In the spring and summer they are fiercely territorial against other birds and even humans.
Yet dozens of male Red-winged Blackbirds visit my feeders together every spring. Earlier this week at least 50 or more of them were sitting closely together in the top of an oak tree just singing away.
The Red-winged Blackbird is a highly polygynous species, meaning males have many female mates – up to 15 in some cases. In some populations 90 percent of territorial males have more than one female nesting on their territories. But all is not as it seems: one-quarter to one-half of nestlings turn out to have been sired by someone other than the territorial male.
Male Red-winged Blackbirds fiercely defend their territories during the breeding season, spending more than a quarter of daylight hours in territory defense. He chases other males out of the territory and attacks nest predators, sometimes going after much larger animals, including horses and people.
