Migration Madness

The night sky in spring may seem serene, where nothing is going on. But in fact, it is bustling with energy and activity.

Why do birds migrate? First, to take advantage of a plentiful food source at their destination. Most birds in forest habitats feed on caterpillars and other invertebrates, fruits, and nectar. All are abundant during the warmer months. Also, there is less competition for nesting territories than in the tropics. During the day, most migrants land to rest and feed. Warblers—small, colorful “butterflies of the bird world”—flit from branch to branch to feed on the caterpillar and other insect “hatches” that they depend on as they migrate north.

Black-throated Blue Warblers (Setophaga caerulescens) winter in the Caribbean and nest in Mountain Laurels and Rhododendrons in mature deciduous forests in the Northeast and southern Canada down through the Appalachians.
Photo by C Wood

Most people don’t look up to notice them in the trees or realize they are even there. Nor do they hear their songs, a combination of trills and buzzes. As long as there are the right native trees, shrubs, and other plants with insects feeding on leaves, you will find warblers and other migrants passing through even in cities.

Worm-eating warblers (Helmitheros vermivorum) are named after eating caterpillars not worms. After spending the winter in tropical forests in the Central America and the Caribbean, they migrate north to breed in mature deciduous forests from Connecticut to Missouri.
Photo by C Wood

It’s not easy being a migrant. Many species of neotropical migrants are experiencing long-term population decline due to habitat loss at both their breeding and wintering grounds, not to mention their re-fueling stops. And there are other threats. Birds collide with skyscrapers, attracted by bright lights at night or fooled by reflections in the glass during the day. Millions are killed every year by predators, such as free-roaming cats. Climate change may make the availability of food out of sync with the birds’ arrival.

Some Blackpoll warblers (Setophaga striata) that breed in western North America migrate up to 6,000 miles (10,000 km) to their breeding grounds after making a nonstop, trans-ocean flight from South America. When you hear or see a blackpoll warbler, the spring’s neotropical bird migration is almost finished.
Andy Reago & Chrissy McClarren / CC BY (https://creativecommons.org/licenses/by/2.0)

What can you do? Actually, you can help birds greatly by providing critical stopover habitat in your own yard or neighborhood. Plant native trees such as willows, oaks, cherries, and birches. For planting information in your area, go to the National Audubon Society’s Plants for Birds or the National Wildlife Federation’s Native Plant Finder. Consider converting your lawn for birds. Our lawns are actually biological deserts and we are a turf nation. The amount of turf in the United States equals the size of New England. Imagine if each year we committed to taking out just some of the grass in our yards, lots, and parks and planted native trees, shrubs, and wildflowers. We would increase our local biodiversity and those warblers might just stop by.

Published by Jim Sirch

Jim Sirch is the author of Beyond Your Back Door, a weekly blog about nature in your neighborhood. He is also Education Coordinator for the Yale Peabody Museum, a UConn Master Gardener and board member of his local land trust. As a trained naturalist, he brings a deep understanding of geology, plants and wildlife and how they interact within a particular ecosystem. He holds a B.S in Forestry from West Virginia University, a B.S. from Miami University in Science Education; and an M.S. in Environmental Studies Administration from Antioch University. He is also the 2014 Sigmund Abeles Award recipient from the Connecticut Science Teachers and Supervisors Association for outstanding science teaching and professional development.

4 thoughts on “Migration Madness

  1. My choke cherry bushes, started from seed from your class a couple years ago, are alive and well. A rabbit gave them( and a cohort of blueberry bushes and ‘possum haw viburnum) a severe pruning in the fall before I could fence them in, but I hope to have a nice feeding stop in a few years.


    1. That’s great and nice to hear from you Patricia! They were chokeberry Aronia, right? I spray mine with deer/rabbit spray occasionally and that seems to help. I also have choke cherry which is another great plant that came in on its own in my yard.


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