Birds, Mainers share migratory tendencies

By Bob Duchesne, Special to the BDN
Posted March 22, 2013, at 3:19 p.m.

“Excuse me, are you Bob Duchesne?”

That is not what I was expecting to hear while strolling the boardwalk at Corkscrew Swamp near Naples, Fla., two weeks ago. I was not aware that my photo was on post office walls in south Florida. Still, the inquisitor was vaguely familiar, and this was a nationally popular birding destination, so perhaps birding was the connection.

It turns out that this couple was on my tour at last year’s Down East Spring Birding Festival in

Lubec …1,800 miles away from this chance meeting in Florida. Small world. But as I pondered it further, it struck me that birds aren’t the only creatures that fly south in the winter. I was one of six Maine birders crammed into a Dodge Grand Caravan, touring the subtropics, and here I was, bumping into two more.

Where do Maine’s birds go in the winter? I have long wanted to write columns and produce slide shows on that topic. But it’s daunting. Once they leave Maine, our birds scatter everywhere south of us. Some linger in this country. Some head for the tropics. A few species go all the way to the southern tip of Argentina. We don’t even know where some go.

One of our most challenging birds is the Bicknell’s thrush. It is an alpine bird that inhabits Maine’s mountains above 3,000 feet. In 1995, it became its own species when it was split from the gray-cheeked thrush, a subarctic breeder that does not nest in Maine. They are similar in sound and appearance, though the Bicknell’s is slightly smaller. They were considered to be the same species until scientists discovered that the two populations do not summer or winter in the same places. Our Bicknell’s thrush spends the winter on the Caribbean island of Hispaniola. The gray-cheeked thrush flies right over the Caribbean and spends the cold months across the northern half of South America. This discovery was sufficient to convince the experts that the two merited separate species status.

The encounter at Corkscrew got me thinking about our birds that don’t migrate out of the country. I spent the rest of the week paying attention to them. For instance, many black-and-white warblers go to central and south America, but some stay in southern Florida. We found them everywhere we went. The same was true for the northern parula, a tiny warbler that was already beginning to sing its territorial song a month before returning to Maine. Pine warblers earn their name no matter where they go. In summer, they are denizens of our white pines. In winter, they are all over the slash pines of the south.

Palm warblers are secretive breeders in Maine, where they nest in bogs. You can find them in the Orono Bog along the boardwalk. They abandon their furtive ways in winter and are likely to walk right under your picnic table in Florida. Yellow-rumped warblers are abundant in Maine each summer, and most will never leave the country. Unlike every other warbler, they are able to subsist on waxy fruit such as bayberries and myrtle, which can be found all along the eastern seaboard.

Note that pine, palm, and yellow-rumped warblers are the first to return to Maine each year. Since they have less distance to travel, they begin to pop up in late April. The northern parulas and black-and-whites are right behind them, arriving around the first of May. It takes several more weeks for the remaining warblers to return from South America.

Ruddy turnstones in Florida make me guffaw. This medium-sized shorebird is skittish in Maine, but not along southern beaches. Flocks forage like pigeons among the beach blankets in the Florida Keys. In fact, shorebird watching in Florida is a very different experience than it is in Maine. First, birds foraging along Maine’s mudflats are nervous. They are transient, unfamiliar with local threats, and subject to predation from migratory falcons. They must feed voraciously in order to store up energy and it is important to avoid disturbing them up here.

But on their wintering grounds in Florida, they spend months on the same beach and get accustomed to people. They barely flinch as birders walk by. Also, shorebirds spending the winter in the subtropical sun bleach out. They are paler in color than those we are familiar with seeing, different enough to challenge an expert, let alone a lowly newspaper columnist.

Some winter Floridians have already returned. Turkey vultures have arrived, tanned and rested.

Bob Duchesne serves as a Maine Audubon trustee and vice president of its Penobscot Valley Chapter. Bob developed the Maine Birding Trail, with information at www.mainebirdingtrail.com. Bob can be reached at duchesne@midmaine.com.

http://bangordailynews.com/2013/03/22/outdoors/birds-mainers-share-migratory-tendencies/ printed on October 1, 2014