Some Interesting Bird Studies

I recently came across a website called Science Daily that collects and publishes articles on scientific studies and related issues. This includes, of course, birds. The link is now over on my steadily lengthening sidebar. Currently there are two interesting bird-related stories.

The first is that birds that migrate early increase their chances of reproductive success. This is not in itself surprising. Male birds that arrive early in the spring get a head start on setting up territories, which is a key component of finding a mate. The interesting part of this study is that birds that finish their breeding early and molt before heading south have an increased chance for reproductive success the following season. The reason seems to be that molting while still on territory, instead of in the midst of migration, leads to brighter plumage. Other studies have shown that female birds prefer brighter plumage in their mates. One of the birds studied was the American redstart, whose display includes fanning its tail feathers to show off the bright red markings on its tail.

The second avian sex story comes from central Asia, where researchers have found a species of eagle whose pairs mate for life. The species is the eastern imperial eagle. Researchers proved that the eagles mate for life through analyzing the DNA found in tail feathers left behind at nesting areas. The technique allowed the research to proceed without capturing the birds, which is important because human interfere can frequently discourage birds from breeding. While many raptors are least somewhat monogamous, not all bird species are.