American tree sparrows were likely the most abundant sparrow around your feeding this winter, but will soon be shifting their breeding grounds. Photo by Ariana van den Akker courtesy Maine Audubon

The spring bird migration is really ramping up, as we’re hearing an audible increase in blackbirds and seeing waterways filled with waterfowl (appropriately). While we celebrate each day with the arrival of new species — I can’t wait for the first eastern phoebe to return, or my backyard pine warbler to be singing from the treetops — I wanted to draw your attention to some of the species that are leaving soon. Maine hosts many species of birds in the winter that will be departing for breeding grounds across Canada’s boreal forest, right up to the arctic tundra. We will get a few more weeks with them, and as their breeding behaviors start to kick in, we have some unique but fleeting opportunities to see unusual actions right here in Maine.

One species we will be saying goodbye to soon is the American tree sparrow. For most Mainers, this would have been the most abundant sparrow around your feeders throughout the winter. It has a rusty cap, unstreaked gray belly with a dark spot on the middle of the chest, brown above with white wing bars, and (if you can see it) a uniquely yellow lower mandible.

While these birds winter in the northern half of the lower 48 states, their breeding grounds shift to the northern half of Canada and into Alaska. This is actually one of the worst-named species (OK, ring-necked duck is worse), since they typically nest in areas where there aren’t trees. They got the name “tree sparrow” because of their physical resemblance to Eurasian tree sparrow. They essentially get replaced by the also similar-looking chipping sparrow, so look closely!

The main reason I want to call them out is because they are starting to sing. As the days get longer, they will start to practice their songs before returning to their nesting grounds. I think of it as one of the rarest songs in Maine, since we get to hear it for just a couple of weeks in March and April. It can be a bit difficult to pick this one out of the cacophony of songs we’re hearing each morning, but the song is a series of sweet high notes, usually with three or four introductory notes, a couple of paired ascending notes, then a few more paired notes that drop in pitch. I tried looking up a helpful mnemonic but all I could find was the onomatopoeic: “e-teeootay-tahtah-geo geo zip.” If that helps you, great, if you’re more like me, you may benefit from listening to a recording on Cornell’s All About Birds website (allaboutbirds.org) or their free Merlin app.

Moving from the woods to the water, there are some really cool ducks in Maine during the winter, and many are going to be leaving soon. Just like the tree sparrow, we can catch these ducks doing some early breeding behavior before they depart. Some ducks actually need to find a mate here, hundreds of miles from where they’ll breed, because they need the open water for doing their elaborate mating displays (and copulating) since they run the risk of finding their summer lakes and ponds frozen when arriving back.

These mating displays are often just as comical as they are impressive: Bufflehead males will quickly scoot around, chasing females and doing quick wing flaps, throwing in the “popcorning” head movements, quickly bobbing up and down throughout. Red-breasted mergansers are worth watching for a while to catch their comical courtships. These already funny-looking ducks, with their messy “hairdo” (feather-do?) and long narrow bills, will toss their heads to the sky before dipping their breasts deep into the water and letting out a loud raspy “yeow.” And black scoters can be seen in large flocks right now, and you’ll often hear them before seeing them: a slightly haunting, downward plaintive whistle. Look it up …

There are also a handful of passage migrants we should keep in mind over the coming months. White-crowned sparrows will make brief stops in your yard during the spring, most commonly in May, before moving north to the boreal forest for summer. And shorebirds are already starting to hit the Maine coast and marshes. Piping plovers, which will stay to breed on Maine beaches, were first reported on March 11. Please be careful if you’re walking beaches, especially with dogs, since these sensitive species are trying to get an early start nesting. Greater yellowlegs, which will breed in wetlands across the Canadian boreal forest, are also being seen in Maine already.

I know many people wait until May to dust off their binoculars and head out looking for warblers and other neotropic migrants, but they’re missing out. The spring push is coming already, and you’ll not want to miss the winter species being pulled north now. American tree sparrows were singing at Gilsland Farm during our weekly Thursday bird walk last week, and should be for a couple more. Join us at 7 a.m.

Have you got a nature question of your own? Email questions to ask@maineaudubon.org and visit www.maineaudubon.org to learn more about birding, native plants, and programs and events focusing on Maine wildlife and habitat. Doug and other naturalists lead free bird walks on Thursday mornings, 7 to 9 am, at Maine Audubon’s Gilsland Farm Audubon Center in Falmouth.