About us: We own the Wild Birds Unlimited nature shop in East Lansing, Michigan,
a store that provides a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Thursday, December 20, 2018

Why don't all the birds leave Michigan in the winter?

How do the birds know to fly south to find food in the winter?
I wrote earlier about how this was going to be a good season for bird watching because Canada’s natural seed crops were horrible this year and lots of birds that usually like to winter further north are going to have venture south to Michigan to find food. Luckily birds have wings and most can forage as far as they need to in search of food for survival.

When the snows hit you'll be able to observe many birds taking advantage of feeders as a supplemental food source. Then come spring they'll heed their hormonal urge to return to a good nesting territory.

But not all birds fly south for the winter. Studies have revealed that more and more southern birds are moving north and sticking around mid-Michigan in the winter. Land development, a steady increase in global temperatures, and bird feeding during the last half of the 20th century may have played a small role in the northward expansion of some southern birds.

For example, the northern edge of the Cardinal’s range has expanded greatly since the days of John James Audubon. Originally a southern bird, the Northern Cardinal began expanding its range into northern states around the 1900’s. After nesting season Cardinals stop defending territories and begin to flock together. During the early days of their expansion they would migrate back south during the winter. But in time they became year round residents of Michigan.

The Tufted Titmouse, Norther Flicker, and Carolina Wren have also been expanding their range northward. Speculation for their expansion includes warming winter temperatures and the increase in mature woodland habitat.

Or take the Turkey Vulture. Once only a southern US bird, by the 1960's they had extended their breeding range into Michigan. The popular theory is that the interstate highway system increased the availability of food in the form of roadkill.

So what do we make of all this? How do animals know when and where to go? The usual explanation is that the migration is driven by instinct, hard-wired into birds. But birds might be evolving. Whether or not a bird flies south for the winter depends a lot on what food the species eats.

Every year we get more and more sightings of orioles, hummingbirds and other birds that normally migrate, sticking around. Amazingly, if a bird can get enough food, they can survive even the worst weather.

That’s why information gathered from the citizen science projects like the Great Backyard Bird Count, along with observations from the Christmas Bird Count, Project FeederWatch, and eBird, helps to us see the “big picture” about what is happening to bird populations. The longer data is collected, the more meaningful it becomes in helping scientists investigate far-reaching questions, like:

• How will the weather influence bird populations?
• Why winter finches and other “irruptive” species appear in large numbers during some years but not others?
• How will the timing of birds’ migrations compare with past years?
• How are bird diseases, such as West Nile virus, affecting birds in different regions?
• What kinds of differences in bird diversity are apparent in cities versus suburban, rural, and natural areas?

Related Articles:
Good News on the upcoming bird watching season https://more-birds-to-visit.html
Birdwatching: Look for the Out-of-Towners http://bit.ly/q6Pkco
How to participate in the Great Backyard Bird Count http://bit.ly/wxa766
Book Recommendations for Michigan Birdwatchers https://checklist-of-michigan-birds.html
Most common winter birds in Michigan http://bit.ly/ywWdfL

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