Episode 28
Copyright © John Page Williams, Jr. all rights reserved.
This is John Page Williams with another reading from Chesapeake Almanac. The month is September and this chapter is called "Terns: Bright Sparks of Life."
My daughter Kelly and I were looking for bluefish at the mouth of the Potomac on a slick calm morning. The fish were spread out, but there were plenty of them around. The largest concentrations were chasing dense schools of menhaden, and several charter boats were working around them.
We, however, found a school of three- to four-inch anchovies dimpling the water like raindrops. Every couple of minutes several bluefish boiled through the anchovy school, which was less obviously visible than the menhaden, so we had it all to ourselves, at least with respect to other humans, which suited us just fine. Kelly caught a couple of six-pounders trolling around the anchovies, and three more by casting when they were breaking on the surface. I maneuvered the boat and handled the net.
Five of these blues were a gracious plenty, so we quit fishing and watched what was going on around us. It was then we realized that we and the blues weren't the only fishermen working the anchovies. There were half a dozen common terns diving on them as well. While the bluefish were certainly impressive as they herded the little silver minnows to the surface and attacked them, the turns showed great skill in hovering over the water, choosing their tiny targets, and diving unerringly onto them. They'd set their wings and plummet like stones, hitting the water with resounding splashes. Almost immediately, they'd recover, reach high with their wings, and pull up away from the river, stopping after a couple of wing beats to shake in midair. I thought of the nickname "minner hawk" which the author John Hay attributes to tern-watchers along the Mississippi Gulf Coast. The terns' skill made even an osprey look slow and ponderous in his fishing and certainly showed up the laughing gulls that were feeding on the menhaden schools.
Intrigued with the birds and curious for more detail, I went home and re-read John Hay's "Spirit of Survival: A Natural and Personal History of Terns. Hay wrote that, on looking at a tern skeleton, he was most impressed with the size of the eye sockets and the large space given over to back muscles. In summer plumage, our terns have black caps which seem to hide our eyes, but those organs are large and bright, sharp enough to spot a three-inch anchovy near the surface from an altitude of 50 feet and then keep track of it during a high-speed dive.
Back muscles are the ones that lift the birds wings, while breast muscles supply the powerful downstrokes. The latter would seem to be more important, but terns spend a lot of time hovering near the water, a maneuver that requires them to reach high with their wings. and they must reach high again when taking off from the water after a dive. It is at these times that those large back muscles play a key role.
Back and breast muscles drive long, narrow wings with pronounced elbows. The wings are too narrow for soaring, which sets the terns apart from their close cousins, the gulls, but turns have more maneuverability. Compared to terns gulls appear to be almost laid back, soaring for long periods and sitting on the water in flocks. Terns seem to be in constant motion, and their wings suit them well.
More than half a dozen species of tern are present on the Bay in the summer and early fall. The common, Forester's, Caspian, and least terns are the most numerous. The first two are what most of us consider "typical" terns. The Caspians, on the other hand, are larger, almost gull-sized with blood-red bills to go with their crested black caps. The least terns are tiny and more likely to be seen on the lower Bay or the seaside Eastern Shore. Other species include the bull-billed tern, which has a black bill, and the royal turn, which is nearly as large as the Caspian but has a lighter orange bill. The most useful distinguishing marks of the species include bill color, tail length, and shading of gray and white on the wings. A good field guide is a big help in distinguishing them.
With a number of tern species living in the same general area, there must be some divisions of diet and habitat to keep them from competing directly with one another. While most terns feed on fish, for example, Caspians feed on smaller birds and eggs, and the gull-billed terns catch insects in flight--yet another indication of aerial ability. Forster's and common terns are very closely related, but the former, which has slightly longer legs, nests in marshes, while a latter, with shorter legs, prefers sandy beaches.
On the Chesapeake, terns breed and nest on isolated marsh islands and beaches. They don't need much land, but they do need security from predators like crows, owls, raccoons, foxes, and black snakes. The chain of Eastern Shore islands that stretches from Barren and Hoopers down through Smith and Tangier provides important habitat, as do isolated spots like the Hole in the Wall at the southeastern corner of Gwynn's Island and the Big Salt Marsh at Poquoson. Least terns appear to be more tolerant of people than the other species and sometimes nest relatively close to cities and towns. Even so, they need large salt marshes like the Grandview Natural Preserve at the mouth of Back River in Hampton.
The nests are casual affairs. Common terns simply scrape out a shallow depression in the sand.If a storm destroys the nest, they haven't invested a lot of labor in it; the terns move, scrape out a new one, and lay another clutch of eggs.
From their nesting colonies, the terns spread out in a broad area to feed. It's quite possible that the terns that Kelly and I watched in the mouth of the Potomac had come from the northern end of Smith or even from South Marsh Island.
Human population pressure is harder on terns than on gulls. While gulls need isolation from people at nesting time, they are opportunistic omnivores that can get by they pick over our trash at landfills in the winter, follow farmers as they till their fields in spring, beg pieces of bread from waterfront public parks in the summer, and feed on scraps from watermen's pots and nets in summer and fall. Terns are much more dependent on fish, especially small ones like anchovies and silversides. They are also susceptible to destruction of breeding habitat, especially the least terns, which lost whole colonies in the lower Bay as marshes were filled and developed before the tidal wetlands laws began to take effect in the early 1970s. They appear to be coming back slowly now, partly due to those laws and partly to good land preservation practices by local governments and private organizations like The Nature Conservancy.
In a month or so, "our" terns will head south, stringing themselves along the coast of Florida and south across the Caribbean to Central and South America. These migrations seem to pale beside the pole-to-pole trips of Arctic terns, but they are immense distances for small birds--a strong testimony to their toughness and endurance. Their long narrow wings allow them to fly into the wind with relative ease, so they can weather storms by working with them instead of fighting their way along.
For now, the terns will be active, feeding as heavily as they can to fuel up for their travels. They won't be as numerous or as obvious as gulls, and it will be easy to overlook them, but they will be there. look for them and spend a little time watching them work. They are bright sparks of life, admirable for their toughness and skill.
