Safe dates. That could refer to romantic encounters where the participants sit 6 feet apart. Or it could refer to a date on the calendar when Maine’s breeding birds are presumed to be finished migrating.
Seriously, how do young people date these days? No movies, no dances, no snuggling? In my day, safe dates meant a chaperone.
On the other hand, safe dates pertaining to bird migration are of utmost importance to the Maine Bird Atlas now in progress, under the auspices of the Maine Department of Inland Fisheries and Wildlife. Volunteers are fanning out across the state, mapping the locations of every breeding bird they can find. Such surveys are conducted every 20 years or so. By comparing current data with past results, biologists can get an idea of how much our environment has changed.
And, yes, it has changed. Although the 5-year project is currently in its third year, trends are emerging. With changes to climate and habitat, we’re seeing southern birds moving north, and northern birds disappearing. Grassland birds are vanishing. Aerial insect-eaters have taken a huge hit. This includes swallows and flycatchers, but also whip-poor-wills and nighthawks.
It’s not enough to know merely which birds are present each year. Some may be just passing through. We need to know which ones are actually making babies in Maine, and where. Since most birds go to great pains to hide their nests, researchers rely on additional clues. A singing male certainly suggests that he’s protecting a nesting territory and seeking a mate. But the hormonal urge to sing often kicks in well before the bird arrives on his nesting grounds. Even some of our year-round birds strike up a chorus long before they’re ready to procreate.
To make sure researchers are counting only breeders and not passers-by, the protocol adds “safe dates” to each species. Any bird showing romantic inclinations before that date is ignored, since it might be just passing through. It’s safe to presume that any bird singing its heart out after that date is trying to mate. The survey counts it as a “possible” breeder in that location.
That’s where it gets tricky. Every species gets its own safe date. Some birds nest earlier than others. Great horned owls start courtship and territorial defense in January. Barred owls and bald eagles get romantic in March. Mourning doves are frisky in April.
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Warblers, vireos and thrushes may not be on their nesting territories until June. If found engaged in romantic behavior after June 1, it is finally safe to assume they are home. A few birds start even later. The safe date for Wilson’s warbler, Canada warbler, bay-breasted warbler, blackpoll, common nighthawk and American goldfinch is June 5. Eastern wood-pewees are typically the last flycatchers to arrive, and it’s not safe to assume they are nesting until June 10.
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Here’s why safe dates matter to you. You can now join the throng of atlas birders, observing the romantic behavior of birds, and not have to worry about whether it’s safe to count them. By mid-June, they’re all safe. One need not be an expert to participate. The project needs data on even the most common backyard birds.
Indeed, some birds are so common, we take them for granted. The project has inspired me to watch my own birds more closely. For instance, there’s a crow sneaking through my shrubs. Usually, crows are brazen. This one is furtive. I’m pretty sure one of the trees in my neighbor’s yard has a nest. Bald eagles also occupy a nest not far from my house. Every time one of the eagles passes by, this shy crow comes alive and charges the eagle, screaming the whole way.
I’m now watching my backyard woodpeckers, chickadees, nuthatches and titmice more closely. All of these are cavity-nesters, and I want to see if any of them are disappearing into holes, especially if they are carrying food. I watched one chickadee improving a hole in an old birch log, while its mate sat nearby. Bingo! Confirmed breeder.
Surveying can be done at home, in the neighborhood, or wherever you go. I found the nest of a northern goshawk near Greenville while walking a logging road a couple of weeks ago. No hawks were on it yet, but the male was circling and calling, in obvious hopes of finding a mate.
Seriously, anybody can do this. Get started by visiting www.maine.gov/ifw/fish-wildlife/maine-bird-atlas/. Help figure out which birds are having unsafe dates during their safe dates.
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 firstname.lastname@example.org.
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