Another week of fall has brought another slate of wacky birds to the Cape and Islands. Whether late lingering landbirds are your thing, or southern seabirds are what tickles your fancy, as usual, we can accommodate you here on this birdy archipelago.
For example, have you ever seen a bird with an underbite? If not, and it’s on your bucket list for some reason, then get on over to Seagull Beach in Yarmouth. Since early October, this beach has hosted an on again-off again flock of up to eight young Black Skimmers.
Skimmers are the only species whose lower mandible is longer than the upper – hence the underbite. But these bizarre relatives of terns and gulls aren’t trying to look bulldog tough – the longer lower bill serves a purpose. Skimmers feed by, well, skimming the surface of the water by dragging that lower beak. When they sense a fish, the bill snaps shut and the minnow is toast. Since they feel for their dinner, they can feed at dusk and even at night, unlike their close relatives. Their brains are apparently quite different from those other species as a result, with a smaller optical lobe and larger sensory areas.
It’s an eerie sight to see a skimmer feeding in the dark – often the disturbance made by that lower bill slicing through the water is all the evidence you have of their presence. The best by far of the colorful old 19thcentury names for these birds was the “cutwater”, especially since the other names, like “flood gull” and “sea dog” didn’t make much sense.
Skimmers are big, striking seabirds. Their “jet black above and white below” plumage gives them that same bird-in-a-tuxedo look that penguins have. And of course there’s that odd, boldly orange and black bill. The longer lower bill isn’t the only strange thing about them – their head is also weirdly bulbous, and at most distances they appear to have no eyes because they blend in with the surrounding black feathers, giving them a ghoulish look.
If you’ve never seen a skimmer around here you’re not alone – they are mostly a southern bird, so we’re at the northern fringe of their range. A few pairs of skimmers have often nested in places like Monomoy or Plymouth Beach, but in recent years Martha’s Vineyard has cornered the market, with beaches near Edgartown hosting most or all of the state’s pairs, which is usually less than 10.
The folks at Biodiversity Works have been working with the Trustees of Reservations and Mass Wildlife to place field readable bands on the Vineyard chicks. Away from the one or two breeding areas, your best bet to see them is at barrier beaches in late summer when young wandering birds tend to show up on occasion, but they are a rare sighting anywhere. But to see them in Massachusetts this late in the year is decidedly strange – this group of young birds in Yarmouth may be the first November record of Black Skimmers for Cape Cod.
Of course there’s a lot more to skimmers than what I’ve told you – if you want to know more you’ll need to do some research on your own. Because in this short essay about this endlessly fascinating bird, I’ve really just barely skimmed the surface.