Was that the call of an eastern phoebe, the small grey bird local to the Upper Valley?
Every spring, hundreds of species of birds can be viewed in the Upper Valley, many of which have migrated back to the area. The Dartmouth sat down with biology professor and ecology, evolution, environment and society program co-chair Matthew Ayres to discuss his work as an ecologist, the migration cycle of birds in the Upper Valley and how students can view birds this spring.
Can you tell me about your background as a biology and ecology professor and the kind of research you conduct?
MA: I’m an ecologist. I study animal populations, especially insects that eat plants and sometimes kill trees, change forests and affect people. I also dabble with birds and bats.
What is the migration cycle for birds in the Upper Valley region?
MA: It’s a marvelous thing. Most organisms, with changing seasons, just have to suck it up and deal with whatever happens. But birds, through the magic of being able to fly, have relatively low costs for transport, so they have the capability to navigate and travel thousands of miles between winter and summer. Around here, you can find 100 plus species of birds pretty easily. Seventy of those are migrants, so they’re just coming back now.
Somewhere right now in Jamaica and in Central America, there are warblers hopping around in mangrove swamps, and they’re starting to get an urge to travel, jump into the air and fly north. They’re not thinking about it, but they are able to perceive that it is approaching the correct time for them to migrate based upon changing photo periods.
Even though the days at this time of year are only changing by seconds per day, birds are actually surprisingly good at perceiving what the length of the day is. They’re able to basically predict what the weather is going to be like 1,000 miles away or farther.
How have climate change and other environmental changes begun to impact migration patterns?
MA: From work, mainly by my colleagues at the Hubbard Brook Forest, we know that in a year when the leaves come out earlier, the birds come back a little bit earlier. Some birds pretty much come back on about the same day no matter what, and some are more responsive. So there’s a variety of things happening. They come back pretty fast. Over the next week there’s just going to be a sea of new birds coming in. It’s so much fun.
What bird species can we expect to see around Dartmouth campus and the Upper Valley?
MA: You could easily see 100 different species of birds without leaving the Dartmouth campus over the next three or four weeks. Cardinals, song sparrows, robins, tufted titmouse and chickadees are particularly common. You can recognize them by their songs. That’s how the professionals do it.
What is the purpose of the bird songs that we hear in springtime?
MA: Bird songs are for mating, territorial establishment and maintenance. The birds that are singing are almost always males. They’re establishing a territory, and they’re telling other males that “I’m here, and I intend to defend this territory.” They’re telling females that, “there’s a male here, there’s a territory.” Males use it to position themselves in space, so they’re really good at distributing themselves across habitat, even as their abundances go up and down. That has a stabilizing effect on their population dynamics. Songbirds account for more than half of the species of all the birds in the world, and arguably it’s because they can sing.
I’ve lost track of the number of students who stopped by a year or more after they took my class, and go, “Hey, I was just walking across campus and I heard a tufted titmouse.” This world opens up. It’s genuinely beautiful.
What advice would you give to students looking to identify birds around campus?
MA: Learn to listen. The singing is by far the most reliable cue to the presence of birds, especially song birds. Everyone can learn and get better just by starting to listen, and it’s fun. It makes you feel good.
This interview has been edited for clarity and length.
