Though I do not believe that a plant will spring up where no seed has been, I have great fai th in a seed. ...
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Martins & Swallows:
The Marsh’s Aerial Acrobats By Rae Griffiths of The Wetlands Institute
Purple martin colony
S
pring is, quite literally, in the air. While fall migration in Cape May is arguably more famous, with the hundreds of raptors, monarch butterflies, and songbirds gathering and waiting at Cape May Point for the perfect conditions to cross the Delaware Bay, spring migration holds many special moments as well. Whether it be the pairs of ospreys returning to their favorite nesting platforms on the creeks; the scores of red knots scouring the beaches along the Delaware Bay for horseshoe crab eggs; or the many species of colorful warblers traveling north from the tropics, the arrival of migratory birds from their southern wintering grounds comes with great anticipation each year. Every spring, we at The Wetlands Institute make special preparations to welcome back two aerial acrobats to the marsh, and this year was no exception. On March 23, we pulled our two “gourd racks” out of the shed and gave the plastic gourds a thorough cleaning before lining each one with a generous layer of fresh dry pine needles. Once these racks were ready, we raised them onto a pole about 20 feet off the ground to create a kind of skyline hotel and awaited the arrival of the first purple martin (Progne subis) “scout.” Scouts
are typically the oldest martins in a population, returning to previous nesting sites; they can be male or female birds. Over the next several weeks, more adults arrive, followed by the subadult fledglings from the previous year. This year, the first scout arrived at The Wetlands Institute on April 3. There are more than a dozen now, and our hope is that by mid-May, more purple martin pairs will fill the rest of our specially prepared gourd nest cavities to complete their nests and lay eggs. Purple martins use the pine straw we provide and add twigs, mud, and finally green leaves before laying an average of four to six small white eggs. The purple martin is the largest member of the swallow family in North America, and represents one of many types of birds that nest communally. Like other swallows, they catch insects as their main food source, swooping and diving about the marsh to grab dragonflies, moths, beetles, flies, and other flying insects – often at altitudes of 500 feet or more (higher than any other swallow). Unfortunately, mosquitos are not a major part of their diet, but we can thank martins for keeping the biting fly populations at bay. On the East Coast, purple martins nest almost exclusively in human-made nest-
Purple martin on a gourd
ing structures, while Western birds use natural nest sites like woodpecker holes in dead snags. Hundreds of years ago, well before Europeans arrived in the Americas, Native Americans used hollowed gourds to attract martins, probably recognizing their value as natural insect control. This, along with a loss of natural nest cavities, likely led to this shift in nesting behavior. While purple martins nest in colonies, preferring to construct their nests in close proximity to one another, continued on page 118
Seven Mile Times June 2023
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