Kirtland’s Warbler, scientific name Setophaga kirtlandii is a small grey and yellow bird native to the area around the great lakes. In the winter, they migrate through much of the US east coast on their way to the Bahamas. They lay 4-5 eggs at a time, which the female incubates for fourteen days, and the young usually stay with their parents for 9-10, once hatched.
It is classified as endangered, and was nearly extinct until the 1990’s, with a population of only ~200 singing males. There are many reasons for this, with the two most prominent being their exacting nesting requirements and cowbird parasitism.
Kirtland’s Warblers require jack pines for nesting. They nest on the ground near young jack pines that are 5-20 feet tall and 6-22 years old. These two factors, height and age, have been found to be crucial for Kirtland’s Warbler’s nesting, though the reason for this is unknown. For a pair of Kirtland’s Warblers to nest, they require at least eight acres of young jack pine surrounding them, and 30-40 acres may be required for raising young.
Kirtland’s Warbler also fall victim to cowbird parasitism. The brown headed cowbird, who wouldn’t naturally be found in the same areas as Kirtland’s Warblers, is a brood parasite. That means that, rather than raising their young, they leave their own eggs in the nests of other birds. Brown headed cowbird hatch before and are larger than most songbirds, so they often push the others out of the nest. Brown headed cowbirds have been able to reach the jack pines forests in Michigan because of the large amount of logging that occurred there, thinning the forests greatly.
There is currently a recovery plan for Kirtland’s warbler, the aptly named Kirtland’s Warbler Recovery Plan. This plan has five main objectives: to develop and maintain 36,000 to 40,000 square acres for nesting by rotation cutting 140,000 square acres of jack pines, protecting warblers along their migration routes, reducing the main factors harming Kirtland’s warblers, monitoring breeding patterns to evaluate their response to habitat changes, and develop emergency measures to prevent extinction.
Kirtland’s Warblers aren’t the only species that need a large amount of space. Many other organisms are also evolved to live in the deep woods, and are unable to transition into other habitats. Habitat fragmentation, discontinuities in an organism’s environment, threaten not only Kirtland’s Warbler, but many other species we take for granted today.Sources:
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When was the recovery plan started? Has there been any population increase since the plan was enacted?
ReplyDeleteThis is a well-organized popular science article. The context is clear and easy to read. The ending is another significant part, for it declares the reason why we should pay attention to Kirtland's Warbler as one of the endangered species.
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