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.