Birders Look Up, Hoping to See Spring Overshoot Migrants

Apr 19, 2017

In last week’s report I griped about our typically cold and wet spring weather here on the Cape and Islands. I submit that it was a direct result of this griping that we then enjoyed nearly a week of atypically warm, sunny early spring weather. You’re welcome.

And while that kind of warm weather in April is good for curing your seasonal affective disorder, getting ahead in your gardening, and laying down your base tan for summer, it also produces one of my favorite ornithological phenomena – spring overshoot migrants.

As we speak, migrating birds are streaming north through Central America, Mexico, and the Caribbean, bound for North American breeding grounds. Many of these early spring migrants breed in the southeastern US, so should be going no further than maybe Georgia or the Carolinas. But under the right weather scenario, some of these birds will get caught in warm packets of northbound air and overshoot their breeding grounds, sometimes by more than a thousand miles. I’ve been known to drive past my exit now and again, but a thousand miles seems a little much. I usually figure it out after a hundred or so.

Over the last couple of weeks, birders have turned up some good examples of southeastern migrants that have overshot their breeding grounds, including the Prothonotary Warbler and Black-necked Stilt on Martha’s Vineyard, a Yellow-throated Warbler in Falmouth, a Tricolored Heron in Harwich, and Summer Tanagers in various places. But in the last few days there have been two reports of my absolute favorite spring overshoot migrant, the Swallow-tailed Kite.

If you’ve never seen a Swallow-tailed Kite, you should try and rectify that as soon as possible. Arguably the world’s most graceful hawk, they essentially live on the wing, where they hunt flying insects and pick small vertebrates from the tree tops. Strikingly black-and-white with a four-foot wingspan and a fifteen inch forked tail, they are hard to misidentify. Your best bet to see them is over swamps and pine flatwoods in Florida and Georgia in the summer, but who goes to Florida and Georgia in the summer?

This is mostly a tropical species, and even the Central American breeding population flies south to the Amazon for the winter. Imagine finding Costa Rica too chilly in winter – this is not a hardy bird. So when we occasionally see them in April on Cape Cod, you know there has been a grave navigational error.

Nevertheless, these overshoots happen almost every year, and the birds recently seen in Orleans and Falmouth could still be around. To find them, you’ll need to look up, because they are not going to come perch in your yard. Falmouth birder Karen Fiske was watching some flying Osprey on Monday when she noted a bird among them that looked like a giant flying pair of scissors. She had been seeing them in Florida just last month, so had no doubt that she was watching a Swallow-tailed Kite. They’ll always be a rare find, but as long as these spring overshoot migrants keep forgetting to stop and ask for directions, we should keep an eye out for them. I suspect they’re mostly males.

Of course, there’s a lot more to spring birding than finding rare birds. The simple pleasure of watching our common breeding birds arrive seemingly overnight, as happened in the last few days with Eastern Towhees, is one of spring’s great joys. So is watching our common local birds swing in to nesting mode, as evidenced by the Carolina Wren that has been collecting my dog’s hair from various surfaces on our deck all day, like some sort of flying Roomba. I may invite him inside – he could save us some serious vacuuming.