With mosquito season nearing its peak after all our rains, so, too, will come the peak of swallows congregating on the coastal marshes in the next few weeks in preparation for their long journey south. The swallows have only started to gather on Plum Island and will peak by mid-August. Along the Parker River Wildlife Refuge on Plum Island, they cover the bayberry and beach plum on the dune side of the road and sit atop the cattails and reeds on the marsh side. Their numbers will climb into the thousands — they look like swarms of giant locusts as they take flight to feed. They often cover the road, forcing cars to stop and proceed at a crawl as the swallows disperse. They bring back memories of Africa when we watched the swarms of queleas cover the road, as well as every tree and bush in sight. Though the queleas were a hundred times more abundant (yes, hundreds of thousands), the mass of swallows that occur on Plum Island every August still conjure up those images.
On a mid-August day, you might find all six local swallow species among the numbers on Plum Island. The majority of the swallows here are tree swallows, probably making up 80 to 90 percent of the individuals. The adult tree swallows have a deep iridescent blue back and bright white front. The young tree swallows are brown on the back. These are the swallows that nest in the boxes that line the marshes in Essex County. Tree swallows are aptly named because they nest in cavities in trees. But a lot of their natural habitat has disappeared, and many tree cavities have been taken over by starlings and house sparrows. Nesting box programs have helped the tree swallow become more plentiful, which, in turn, helps curb the flying insect population around the marsh areas where they breed. Adding a nesting box to your yard if your live near a field or marsh might attract these beneficial birds to your yard in the spring. You may recall that we had a pair of tree swallows nesting in a house outside of our store a few years ago.