Friday, September 21, 2012

Do all birds migrate?

In general, it's estimated that of the over 200 species of birds nesting in Michigan, about 90 percent migrate to some extent. Whether it’s from the U.P. to mid-Michigan or from our state to Mexico or Central America depends on the bird.

.In Michigan, birds can belong to several groups:

Permanent residents or non-migrating birds like Downy Woodpeckers, Black-Capped Chickadees, White Breasted Nuthatches, or House Sparrows are common year round residents..

Summer residents like the Ruby throated hummingbirds, orioles, swallows, or rose-breasted grosbeaks arrive in our northern backyards in the spring, nest during the summer and return south to winter.
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Winter residents like
Red Breasted Nuthatches and juncos, not seen in our area during the summer, think mid-Michigan is the perfect place to spend the winter..
 
Transients like the White-throated and White-crowned Sparrows are migratory species that nest farther north than our neighborhoods, but winter farther south and we see them only a few weeks during migration, as they pass through.
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Other bird species seen at the feeder year round may also be migratory. While we see
American Goldfinch throughout the year, some of the ones we see in the winter may have nested in Canada. And Song Sparrows that breed in Michigan may migrate to the southeastern United States, or may remain a year-round resident. They are obligate partial migrants, meaning only part of the population migrates annually. And sometimes circumstances such as a good breeding season followed by poor winter crops can lead to irruptions of bird species not normally seen in our area like the Pine Siskins or Redpoles.
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It’s not easy getting every bird’s travel plans straight. For example one my favorite birds, the
Northern Cardinal, has expanded its range greatly since the days of John James Audubon. Originally a southern bird, the cardinal began expanding its range into northern states around the 1900’s. During the early days of the expansion the birds would migrate back south during the winter, but in time they became a year round resident in Michigan.
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Migration isn’t an exact journey. Using published literature, bird observer reports, and observations of bird watchers it has been found that many factors like the temperature changes and land development are very likely influencing birds’ migratory patterns and will continue to alter patterns in the future.

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