Purple martins swarm South Jersey

The bird population in a tiny town in South Jersey swelled this month by the thousands. Purple martins fly in from hundreds of miles away to mark the end of another summer by gathering on the banks of the Maurice River. WHYY’s health and science reporter Kerry Grens visited the birds and has this report:

The sun is sinking west of the Maurice River in Cumberland County. A few gulls swoop overhead, but aside from the cars that pass over the river’s bridge, the scene seems pretty still.

Jackson: I think we need to get up on the bridge so we can see the birds coming in.

Allen Jackson is considered the area’s foremost purple martin expert and enthusiast, though it’s hard to believe some of the things he says.

Jackson: We estimate that there are over a quarter million martins that come in here each night.

A quarter of a million birds? We walk up the bridge. Light is fading fast. But I don’t see any birds. Jackson sets up a spotting scope, focused on marsh reeds about a quarter mile from the road we’re standing on.

Jackson: Look through here. Look in the sky. Ok?

Almost on cue, the black birds — countless numbers of them — lift from the marsh and circle frantically.

Jackson: Ok, now that is a good swarm. They were scared up out of the phragmites by something and so they’re just flying around in the sky. They’re everywhere Tom, you know?

Tom is Tom Millard, a birder from northern New Jersey. He came down to see this annual spectacle for the first time.

Millard: That was a lot of martins! I’m a bird watcher so I see a lot of birds. But I think that’s probably the most I’ve seen in one spot of any species of birds.

Millard is what’s called a “purple landlord.” He manages a small colony of martins by a lake near his house. Earlier this year he noticed one of his birds was wearing a purple anklet. It turned out to be a bird that Allen Jackson had banded a few years ago in Millville.

Millard: I don’t know how he found my little place in the mountains of northern New Jersey, but he likes it. This year with his mate they produced seven eggs of which six hatched. He might be out here tonight.

Birds from New England, Pennsylvania, Maryland and Delaware join the New Jersey birds at this roost. It’s a staging area before they leave for their wintering grounds in Brazil. Jackson has been banding the birds for a decade, as part of research through the US Geological Survey to understand more precisely where the birds travel. He banded eight thousands Martins this summer — including one from South Jersey that joined a colony in Louisiana.

Jackson: Which is just blowing everybody’s mind, that’s so far away from the natal colony where the bird was born. So we’re just getting all sorts of neat information.

When asked why he’s so passionate about purple martins, Jackson can’t say.

Jackson: I really don’t know. Other than, my martins know me. I go out each day – may sound stupid – but I go out and talk to them. They know what I look like, they know what I sound like.

The birds are necessarily close with humans; they are totally dependent on us for their habitat — those gourds and bird houses people put up in their back yards. Jackson does a lot of education work to get younger people interested in becoming purple landlords.

Jackson: They are very hard to attract but once you get them they have a very melodious song that you just love to hear…

Like this song a birder showed me on his iPhone.

Jackson: …and when they leave it seems like silence all around. As the light disappears, the birds drop back down to the reeds for the night. By early September they’ll be gone, and Jackson will anxiously await their return in the spring.