Birds

Summer Ocracoke beauties: Black Skimmers

Black Skimmer in flight. Note the much longer mandible. Photo: P. Vankevich

By Peter Vankevich

Among the many reasons to visit Ocracoke is that most of the island is part of the Cape Hatteras National Seashore and is undeveloped.

In the so-called off season–fall into spring–one can walk in places along the roughly 13 miles of beach and not see another person. But one is never alone. Scurrying around could be Sanderlings racing back and forth feeding at the intervals of the ocean’s ebb and flow.  Often, just beyond the breakers are frolicking dolphins.

As interesting as fall and winter can be, summer also has its natural beauties, two being spectacular black and white plumaged birds with unique colorful bills. They are the American Oystercatcher and the Black Skimmer, this month’s feature.

Primarily crepuscular feeders, Black Skimmers are best seen in early morning and from late afternoon into dusk gracefully gliding inches above the waterline in the surf.

Identification is not challenging. Their long, pointed black wings and white forehead and underparts are distinctive along with a large reddish and black bill.

Unlike any other North American birds, its asymmetrical bill structure is unique. The upperpart, called the maxilla, is noticeably shorter than the mandible, the lower half.  This unusual structure permits it to forage while in flight by skimming with its bill open, snatching up small fish.

Highly sociable, skimmers nest on open sandy beaches and sandbars and create a shallow scrape in the sand to incubate their eggs. It takes about 25 days from hatching to flying and the young are entirely dependent on the parents for feeding and care.

This season, about 220 pairs are nesting on the South Point of the island. Colonial water birds, they are comfortable nesting there alongside Least, Common and Gull-billed terns.

There is also a small colony of skimmers on Big Foot Island nesting alongside Royal and Sandwich Terns. Big Foot is the dredge spoil island in the Pamlico Sound off Ocracoke where the Cedar Island, Swan Quarter and passenger ferries pass by.

These locations make them susceptible to overwash due to storms during the critical nesting period before they can fledge. So far this season, no major storms have caused any harm.

But storms are not the only threat as there is a plethora of natural predators on Ocracoke as in many nesting areas. Mink, raccoons, feral cats and even ghost crabs can eat the eggs and young chicks. Unleashed dogs can be another problem.

And among the avifauna, there is no solidarity of “us birds against the rest of the world” as large gulls and black-crowned Night Herons, among others, prey upon the young and eggs.

One notable major nesting disaster occurred in 2015 on San Marco Island, the largest nesting colony in Florida, when a group of eight to 16 crows ate their way through a colony of about 600 nesting adults wiping out an estimated 1,000 eggs and young chicks for that season. This year, with careful monitoring, those in Florida are doing fine so far.

Head out to the beach from late afternoon into dusk and watch them fly closely by.

If you want a double-header nature experience, bring flashlights. As darkness approaches, look for the ghost crabs emerging from their burrows to head to the water to rehydrate. Tip: larger ghost crabs tend to be around the dunes.

 

Black Skimmer’s evening foraging on Ocracoke. Photo: C. Leinbach