Flat-out Fun

November 16^th, 2023 ~ This outing took place back in November, when the upper Gulf Coast was finally cooling off. The weather reports predicted cloud cover without rain, so I headed to Bolivar Flats, at the southern tip of the barrier island that extends along our Texas coast northeast of Galveston.

Grooming thousands of feathers, one at a time
1/2000 sec. f/5.6 ISO 2000
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)
(Click on any image once to enlarge in a new window; close that window to return here.)

A Long-billed Curlew, Numenius americanus, was using his long elegant bill to deal with one pesky feather…

Long-billed Curlew, at seaside
1/2000 sec. f/5.6 ISO 2000
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

…and then he posed for us, so we could see ALL of his (or her) bill.

I wondered about the little indentation near the tip of his bill, worrying that he had been injured. Nope. Long-billed Curlews, like many sandpipers that probe along the water’s edge for their favorite crustaceans and mollusks, have a specialized nerve center in the tip of their bill, sort of like the tip of your finger, that senses minute changes in water pressure as water passes objects in saturated soil (it is actually much more sensitive than your finger).

Ruddy Turnstones having a spat
1/2000 sec. f/5.6 ISO 2000
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

Two Ruddy Turnstones, Arenaria interpres, down from the Arctic for the winter, were arguing loudly. The aggressor kept after the subservient bird for several minutes, until finally the subservient bird actually lowered his tail, extended his neck, and laid his chin on the ground. The aggressor lifted one foot as if he was going to stomp the cowering bird’s face, but relented, and flew away, still squawking in agitation.

These two are showing their winter plumage, faded so as to blend almost perfectly into the wrack along the shoreline. I’m only sharing one shot of the action because a danged piece of trash spoiled the other images. I was able to remove it from this image, but in the others, it couldn’t be removed without impinging on the feather detail.

Graceful American Avocet
1/1600 sec f/5.6 ISO 2500
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

An American Avocet, Recurvirostra americana, placed one delicate blue foot thoughtfully after the other. Their blue toes are partially webbed, allowing them to swim for short distances. Their bill is curved upward (recurved), and the female’s bill is more sharply curved than the male’s. Chicks hatch with a much shorter, straight bill, but develop the long recurved bill by the time they are adults. Avocets typically feed by scything (stroking their bill side-to-side through shallow water, feeling for prey). It is not a common behavior; Roseate Spoonbills are one of the few other birds that use this method of feeding.

American Avocets in winter plumage
1/2000 sec. f/5.6 ISO 2000
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

A pair of American Avocets flew by in perfect synchronization. They often fly in unison, and they also flock in the shallow water in unison, all pointing their heads one way and their tails another. In the winter, they are black and white; during the breeding season, their head and neck will develop a pale cinnamon blush.

Black Skimmers at Bolivar Flats
1/2000 sec. f/5.6 ISO 2000
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

I was thrilled to see Black Skimmers, Rynchops niger, flying formation just above the gentle surf. Seeing skimmers skimming has been on my list of desired images for several years. Maybe I would get lucky.

A Black Skimmer cutting across the water
1/2000 sec. f/5.6 ISO 2500
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

And there they were! A small group of approximately twenty skimmers flew back and forth, at one point coming within about 75 feet of the water’s edge.

Black Skimmer fly-by
1/2000 sec. f/5.6 ISO 2500
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

The birds wheeled and returned along the shallow surf line, then turned again for another run. Black Skimmers feed all day, but are most active at dawn and dusk. Their eyes have narrow vertical slit pupils, like those of a cat, which give them excellent vision in near-dark situations, permitting them to feed at night.

Black Skimmers, skimming
1/2000 sec f/5.6 ISO 2500
Nikon D850 with Nikkor 600mm f/4 + 1.4x TC (850mm total)

In the image above, the bird in the foreground is an adult in non-breeding plumage, showing gray dappling along the neck and shoulders. In breeding season, this will be sharp well-defined black against the rest of his pure-white body.

The skimmer has an unusual bill. They are in the Family of gulls and terns, but unlike the gull’s thick cylindrical bill, the skimmer’s bill is shaped like a knife blade, wide from top-to-bottom for strength, but almost invisibly thin from side-to-side, for slicing through the water. Although the birds hatch with upper and lower bills of the same length, by adulthood the lower bill extends a good inch farther than the upper bill. The young can grasp their own ground-dwelling bugs or crabs, but the adults eat only water-borne animals (mostly fish and shrimp in the winter) that they trap when the water sweeps the prey between their bills, triggering a reflex that snaps the upper bill down on the captured prey.

Range maps for four species of birds found in winter at Bolivar Flats, courtesy of All About Birds

The wide expanse of Bolivar Flats is perfect for watching birds in, on, near and above the water, as the flat landscape doesn’t hinder visibility, and you can wander freely over the sand, between ponds, dunes and tidepools. The eBird hotspot map shows over 300 species of birds have been recorded here at the Flats, and as you can see from the range maps of each bird featured in this post, the Flats offer a safe and productive winter ground for many of those species.

The skimmers are here year-round, but the avocets, curlews and turnstones are only here in the winter. It was fun to see such a wealth of birds, and to range with them across the Flats.