A Bird That Blew in the Back Door
In recent years frequenters of open space in the southern part of the country have been intrigued by a white bird, as tall as a chicken but not nearly as fat, that stalks grassy swards and pauses occasionally to wriggle its long neck in an ornithological version of the twist. The eye-catching newcomer in our midst is the cattle egret, Bubulcus ibis, an Old World heron that is causing the biggest stir in American bird watching since the passing of the last heath hen.
The cattle egret is the first bird in history to invade this continent without an assist from man. Other exotics, including the European starling, the Chinese pheasant and the English sparrow, were all brought in and deliberately liberated in the hope that they would like it here. (Some liked it only too well.) The cattle egret has come of its own volition, sneaking past border guards down South so unobtrusively that it was not discovered until it had made itself at home. Now it is found all over the East and as far north as Newfoundland, and almost overnight, as such things go, it is on the way to becoming common.
Bubulcus ibis caught bird watchers and professional ornithologists with their binoculars down. It is clear now that the bird had been stalking around in cattle pastures and meadows for some years before the birders became aware that there was a new species in town. It was not until April 23, 1952 that the first specimen was taken for scientific reference. Three birders, W. H. Drury Jr., A. H. Morgan and R. Stackpole, took the historic bird near Wayland, Mass.
The stranger achieved anonymity by the simple expedient of mingling in groups of its American cousins. Bird watchers were so used to seeing flocks of white herons out on marshy meadows and pastures that it never occurred to them to look closer for the buff-colored feathers on the crown that mark the cattle egret. During the breeding season this orange-buff color spreads down the neck and onto the upper back. One birder, Richard Borden, photographed some white herons on a Florida ranch and did not learn until later that cattle egrets were among them. He described his mortification at being the first man to photograph the new bird in America without knowing it in an article in the Bulletin of the Massachusetts Audubon Society. It was entitled Was My Face Red?
Alexander Sprunt Jr., who was leading Audubon tours in the same area at the same time, frankly admits that he was hoodwinked by the bird.
"My only explanation," he wrote for the Smithsonian Institution, "lies in the fact that white herons feeding with cattle were so much a part of the local scenery that they were simply pointed out to visitors as such, often at some distance."
It must be admitted on behalf of the embarrassed birders that from afar the cattle egret can easily be mistaken for the snowy egret or, perhaps, the little blue heron in its immature white plumage. But at close range the differences become apparent—not only in the buff coloring but in the stouter bill and in the legs which are yellow to dull reddish during the breeding season. It is not known just how long the bird had been getting away with its little game, but once the ruse was discovered the birders went after it like hounds on a hot scent.
Credit for being the first to find a nest of the cattle egret in North America goes to Samuel A. Grimes of Jacksonville, Fla. and Glenn Chandler, an Audubon warden. On May 5, 1953 they discovered it and the one egg it contained in a rookery on King's Bar, an island in Lake Okeechobee. Other nests later were found in the same rookery. The immigrant had moved right in and was sharing accommodations with native herons and all the other residents of these populous bird towns. The nests were loose platforms of sticks similar to those of other herons and usually contained three or four bluish-white eggs.
In the decade since 1952 the cattle egret has made good progress in its adopted land. Its numbers built up rapidly in Florida, and reports began coming in from the Atlantic seaboard. Several years ago I visited Fort Jefferson National Monument in the Dry Tortugas, across 65 miles of ocean beyond Key West. There, marching around the parade ground of the massive, pre-Civil War fort, were half a dozen cattle egrets.
Once they got a foothold, the birds displayed unusual tameness as they paraded around golf courses, airports and grassy roadsides in an endless search for insects. Those who watched a group for very long were sure to see them do the twist with their necks. No native American heron goes in for these curious gyrations. A cattle egret will be staring ahead intently when suddenly its neck will begin to undulate in a snaky rhythm. The dance, if that is what it is, is brief. While it is in progress the head appears to remain still. Sprunt describes it as a hula motion. Twist, hula or Indian rope trick, it is a comical habit and should be investigated further.
In this country the birds have proved their strong affinity for cattle. They stay close to the feet or grazing muzzles of their mammalian friends, snatching insects flushed by the cows. In return for this service they pick ticks and other insects from them. They walk right under cattle, and it is a wonder they do not get stepped on—but they always ease aside just in time. Sometimes they perch on the animals' backs. Mrs. Sprunt saw one following a cow, and when the cow entered the water to wade in a canal the egret hopped onto its back.
In 1961 the bird was doing so well that veteran bird man Allan Cruickshank saw a roost of 30,000 of them on Merritt Island, most of which is being taken over for the Cape Kennedy base. Birders making their Christmas counts in Florida reported a total of almost 10,000.
Then, in the spring of 1962, the cattle egret underwent its own population explosion. Riding air currents the birds pushed up the Atlantic coast all the way to Nova Scotia. Audubon Field Notes, the compiled records of many observers, reported them not only in New England, New York and New Jersey but out in Ohio, Illinois, Wisconsin, Minnesota and even Oklahoma and inland Texas. The first nesting for Canada was reported from Ontario.
Previous movements were mild compared to this eruption, which carried the birds over half the country and raised a few questions. Will the cattle egret compete with any of our native birds? Will it prove destructive or become a nuisance? Will its healthy appetite for insects prove beneficial on ranches afflicted by grasshopper plagues? Will it turn its appetite to other things? The bird bears watching—and it will be watched.
While awaiting the answers ornithologists have turned backward in their investigations to find out how the cattle egret got here in the first place. Having failed to find any evidence of a human assist they are pretty well agreed that a band of the birds probably rode the prevailing easterlies from Africa to the South American coast. A search of the records indicates that the first South American specimen was taken in British Guiana in 1937.
Later there were sightings in Venezuela, the Netherlands West Indies, Surinam and Colombia. Once Bubulcus ibis became established in South America only a little island-hopping was necessary to bring it to this country.
Although the sneakiness of its arrival here may be deplored, the birding fraternity is now alert to the opportunity of studying a species in the process of taking over and becoming adjusted to a vast new territory. What migration patterns will it establish? Will the western mountains prove to be a barrier? (English sparrows crossed the Continental Divide by riding in empty grain cars.) Will the bird itself undergo changes in its new environment? Dr. Robert Storer, curator of the U. of Michigan's Museum of Zoology, has suggested that a hundred specimens be taken now and preserved so that future scientists may make comparisons.
The questions posed by this slippery invader are many, but now hundreds of the nation's bird watchers are on its trail, determined to round up as many of the answers as they can. It is highly doubtful that Bubulcus ibis will be able to pull any more fast ones.
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