Sunday, June 02, 2013



The raucous Red Winged Blackbird is an easy bird to identify, and very common any place where there is a bit of water. The black males have a red shoulder with a yellow band below. Most of the photos I have show him with mouth open. When the nest is nearby, he is constantly defending his territory or chasing away intruders.

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. No wonder he's always so defensive!

Occasionally, you may see a black bird with only the yellow band. Is that a different kind of bird? A juvenile perhaps? No, it is the adult may when he's not in an assertive mood. At feeders he'll look like this, sending the message "Hey guys, I'm just looking for a bite to eat and don't want to start a fight right now."

His seldom seen mate is also a very attractive bird. The first time we ever saw one we spent half an hour searching through all the sparrows in the field guide looking for the biggest sparrow we could imagine! Of course, she must blend in with the cattails where she builds her nest.

When you live in the marsh, you have to land on anything available, even if you do the splits!

The female of any species lays only one egg per day. The brown splotches on these are added just before they are laid, and each egg has a different pattern. Looks like they've been pooped on. Predation of eggs and nestlings is quite common. Nest predators include snakes, mink, raccoons, and other birds, even as small as marsh wrens. The Red-winged Blackbird is occasionally a victim of brood parasites, particularly Brown-headed Cowbirds. Since nest predation is common, several adaptations have evolved in this species. Group nesting is one such trait which reduces the risk of individual predation by increasing the number of alert parents. Nesting over water reduces the likelihood of predation, as do alarm calls. Nests, in particular, offer a strategic advantage over predators in that they are often well concealed in thick, waterside reeds and positioned at a height of one to two meters. Males often act as sentinels, employing a variety of calls to denote the kind and severity of danger. Mobbing, especially by males, is also used to scare off unwanted predators, although mobbing often targets large animals and man-made devices by mistake.

No comments: