The Ordeal of the Wood Ibis
Northerners fighting snowdrifts during the grim winter just ending smirked when they learned of pallid tourists fleeing Florida in droves and of hotel owners crying the blues and holding out free meals as bait. Ice on palm trees may be funny from a distance, but to Flondians adding up the state's losses it was no smirking matter. To fleeing tourists they had to add ruined citrus crops, frostbitten vegetable farms, dying cattle—and dead storks.
The storks were wood ibises, the only true stork in the United States. The wildlife losses of the winter are hard to evaluate in numbers, dollars or esthetic values, but in the case of the wood stork ornithologists have come up with a detailed picture of what happens to subtropical bird colonies when hit by cold, rain and wind. The past winter may have an important bearing on the continuance of wood storks as a part of the rich bird life which attracts so many visitors to Florida.
The record is more detailed for the wood storks because ornithologists, already worried over their declining numbers, were making a study of the species when the winter storms struck. Drought, drainage, lumbering and other factors have affected the status of this spectacular bird. Twenty years ago there were more than 100,000 of them. Today their numbers probably do not exceed 4,000.
During the two previous winters their nesting efforts in the Corkscrew Swamp, which had the largest remaining colony, had been unsuccessful because of excessive drought. This swamp, with cypress trees more than 800 years old, is a sanctuary owned and guarded by the National Audubon Society. When I visited it 19 years ago it harbored 15,000 wood stork nests.
Last fall conditions were right for a good nesting. There had been rain; sloughs and ditches were full of water; minnows, crayfish and other natural food were abundant. As though to compensate for their previous nesting failures the wood storks soared into the big cypress trees and began nesting earlier than they ever have before.
On November 20 Warden Hank Bennett, custodian of the colony, was elated as he watched the wood storks coming to the nesting trees. On wings spreading five feet or more they circled over the swamp, then dropped their landing gear as they approached the treetops. The first eggs were laid on November 29, and Hank heard the voices of the first young on December 29. A later airplane reconnaissance resulted in a final estimate of approximately 1,000 breeding pairs.
By January 1 many young had been hatched, and the colony was off to a good start. Things were looking up for the race of wood storks. At 11 o'clock on that same night a light rain started, accompanied by a little wind. By midnight the rain had become heavy and the wind, which was from the north, increased with gusts up to 20 miles per hour. At 7 a.m. on January 2 all adults were sitting, but no young could be heard. Light rain and a steady wind continued, and the temperatures dropped sharply. The wind rose during the night and probably reached 30 miles per hour.
On January 3 the rain began to let up, but the wind remained high and the temperature low. In the afternoon an inspection of some of the nests indicated that two-thirds of them were deserted. Crows, turkey vultures and black vultures were flying over the treetops. Later, vultures were observed standing on deserted wood stork nests. Late in the day the rain stopped, but the wind increased to 35 miles per hour and the temperature dropped below freezing. On January 5 a few birds with eggs were still sitting. On January 6 the wind was 20 miles per hour. Five adult wood storks observed the day before were missing. By January 12 all nesting attempts had ended. Ornithologist Alexander Sprunt IV wrote: "Two wood storks seen over the trees. There isn't a single occupied nest anywhere in the swamp."
By this time the nearby farm lands were inundated, and Sprunt wrote of the curious sight of fruiting tomato plants under water.
THE LAST COLONY
Five smaller colonies which the wood storks had established in south Florida suffered fates similar to the one at Corkscrew. A colony of 150 nests in the Sadie Cypress was wiped out by the same storm. A small colony of 25 nests was lost at Monroe Station. On January 12 there were two colonies still hanging on in the Everglades National Park, one at Cuthbert Lake and one at East River. Dr. William B. Robertson, park biologist, found about 300 pairs at each place. They had survived the first storm, but in late January another storm knocked out both colonies.
At the end of January, Robert P. Allen, ornithologist studying the wood storks, took me along to check the only remaining colony, a group of only five nests in Joe Bay at the southern tip of the Florida mainland. The five nests were deserted. Allen pointed out that normally there is an annual loss of about 30% among the adult birds.
Fifty years ago, when the American and snowy egrets were nearly wiped out by the plume hunters, the wood storks escaped because they lacked the fancy plumage then so much in demand. In succeeding years they prospered, and there were many rookeries in Florida. Then the drainage of the Everglades, coupled with the severe drought of the '30s, deprived them of much of their feeding ground. In addition, lumbering operations continued to take away the big cypress trees in which they preferred to nest. Now the perils of cold weather during their nesting season are making it still harder for the wood storks to survive.
"If they don't get a successful nesting soon," Allen said, "the wood stork will be added to the list of rare birds."
PHOTO
DAVID GOODNOW