Many birds return to Maine in April. Here’s what to look and listen for.

This is the week the floodgates open. Up until now, there has been a steady trickle of birds migrating back into Maine. From here on, all heck breaks loose.

Common grackles, red-winged blackbirds and turkey vultures showed up before the end of March. Ospreys and great blue herons began to arrive during the first week of April. American robins and song sparrows came back around the same time. A week later, eastern phoebes followed.

Typically, I can hear spring arrive. I grab a cup of coffee first thing in the morning and step onto the porch for a quick listen. Most migrants arrive overnight and sing the next morning. Local birds also get noisier as winter releases its grip on them and spring turns their thoughts to love. This is such a loud phenomenon that I am now starting to hear spring arrive in other people’s ears. I get emails from readers.

Lately, I’ve received more than the usual number of messages from folks wondering what bird is making a whistled “sweetie” call. The first note is higher than the second. Sometimes, it’s three notes: “Hey sweetie.” Many people are surprised to learn that this is the song of the black-capped chickadee, sung to defend territory and attract a mate. The “chickadee-dee-dee” is their call, used for warnings and conversation. Although they can sing the song any time of year, the competition intensifies in mid-April, so they’re particularly vocal now.

Carolina wrens are popping up in greater numbers. I have received more than the usual number of emails recently, wondering what that loud, persistent, almost obnoxious bird is, flitting furtively around the backyard and singing “tea-kettle, tea-kettle, tea-kettle.” It’s a common bird from Florida to Massachusetts. It is one of those species that is moving north as the climate warms. They’ve reached eastern and northern Maine over the last decade. We’re at the top of their range, and a hard winter can knock them back a bit. But this was not a hard winter, and their loud song has been penetrating more backyards than usual this spring.

Starting today, and any warm, quiet morning, you are likely to hear the tidal wave of migrants returning. The first three warblers to arrive are pine, palm and yellow-rumped. Blue-headed vireos and ruby-crowned kinglets arrive this week. Yellow-bellied sapsuckers should become noticeable. Their unique, uneven drumming pattern will commence in every wooded neighborhood, and this is the woodpecker that most loves to bang on metal. Our other migratory woodpecker, the northern flicker, also arrives this week.

Tree swallows are back, the first swallows to arrive. Most early migrants have one thing in common: They never left the country. While the winter range of tree swallows includes Caribbean islands and Central America, it’s also a common winter bird throughout the southern states. Ditto for some of the more secretive birds — such as American bittern, American woodcock, hermit thrush and winter wren — which all had a short flight to their breeding grounds in Maine, arriving with little fanfare.

Broad-winged hawks are the long-distance exception. They will flood in on the first favorable wind this week, coming up from a winter spent in Central and South America. When it’s time to head north, a southerly breeze triggers many of them to ride the air current together. At a hawk watch on Bradbury Mountain in Pownal, only one had been seen as of last Friday. But when they arrive, hundreds pass the summit in a single morning. You should start to see them any minute now.

Maybe I’m too late in offering this wisdom. The relatively short winter has encouraged an early migration for some species. The eastern phoebes in my neighborhood arrived about four days earlier than usual — the sign of an early spring, or climate change, or a restless urge to travel, which a lot of people also have. The kinglets, flickers and pine warblers were also a week early at my house.

The flickers were especially amusing. They came in last Friday night. On Saturday morning, two males were already wooing a single female. One of them is going to be disappointed. Maybe both. After her long tiring flight, she seemed disinterested.

Enough said. Take this newspaper and a cup of coffee out onto the porch and listen. Once you know what your backyard sounds like, you might be surprised to hear your own birds returning. You may hear birds today that you didn’t hear yesterday. Spring is here, and it sounds terrific.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.