A record number of whooping cranes are wintering along the Texas Gulf coast. Aransas National Wildlife Refuge near Rockport and the surrounding area are home to 237 whooping cranes, up from 220 a year ago.
United States Fish and Wildlife Service Biologist Tom Stehn has been monitoring the birds since 1982. "I'm going on my 25th year with the whooping cranes," Stehn said. "The number of birds here at Aransas has basically tripled in those 25 years."
Stehn attributes the 17 bird increase to extremely good nest production last summer. A record 62 nesting pairs fledged 49 chicks on nesting grounds in the Northwest Territories of Canada.
"It is really satisfying because the recovery efforts are working, but it is kind of like a detective story where you are not sure how it is going to come out," Stehn said. "Every year you don't know whether there is going to be more or less than the previous fall."
Whooping cranes almost disappeared by the middle of the last century due to hunting and habitat loss. "They were down to 15 birds back in 1941, and of those 15 birds about four of them were adult nesting females," Stehn said.
They may not have ever been very numerous, and it has been estimated that only 500 to 1,400 whooping cranes inhabited North America by 1870. In addition to shooting and extensive habitat loss several other factors contributed to their decline. Many cranes died from collisions with power lines while others succumbed to disease and lead poisoning.
Their long migration from Canada to the Gulf coast exposes them to many natural hazards such as sleet, snow, hail storms and droughts. Also, whooping cranes delayed breeding maturity and small clutch size renders the population less capable of rebounding.
Larry Ditto of McAllen, retired United States Fish and Wildlife Service biologist was assistant manager at Aransas 36 years ago. "I was there in 1971," Ditto recalled. "It was my first station from 71-74. There were only 57 cranes, and we were scared to death that something would happen like an oil spill."
"They were the largest bird I ever saw, but the thing I will always remember is the call," Ditto said. The call is like a bugle and will carry across the marsh for miles. It is kind of hard to describe, but it is one of those magic calls of the wild you will never forget. To me it is right up there with the howl of the wolf, a loon, or an elk bugling. Those are the four calls of nature that I find outstanding."
Whooping cranes are the tallest birds in North America with adults standing nearly five feet. Mature cranes are white with a conspicuous red crown and a long dark pointed bill. Black wing tips can be seen in flight on adults. They have a wingspan of seven and a half feet.
Their only known breeding ground is in Canada at Wood Buffalo National Park and adjacent land. This remote location was not discovered until 1954, when a pilot spotted a pair of the rare cranes.
They do not reach breeding maturity until they are four years old, and they establish life long mates. In early spring, sometimes while still on their wintering grounds in Texas, they initiate enthusiastic courtship dances consisting of wing flapping, head bowing, strutting and tremendous leaps into the air by one or both birds. This is accompanied by loud, bugle like trumpeting.
They nest on the ground in late April to mid May, usually on a slightly raised area in a marsh. They normally nest only once each year, unless their first clutch is destroyed and then they will sometimes lay another. Occasionally, they will skip a nesting season if conditions are unsuitable such as when drought prevails. The female lays one to three eggs with hatching occurring a month later. The parents share incubating and rearing duties, but females assume the primary role in feeding. However, usually no more than one young survives. Whooping cranes can live for some 25 years.
Chicks have reddish-cinnamon colored feathers, and while they can swim almost as soon as they hatch they will not fledge for nearly three months and are vulnerable to predators. Slowly over their first winter juvenile plumage is replaced. By the following spring they are mostly white, with full adult plumage achieved by late in their second summer.
This winter, a record 45 young cranes completed their first 2,400 mile migration to Texas. Particularly noteworthy, were seven whooping crane pairs with two chicks each. "The presence of seven families with two chicks each is especially exciting since it surpasses the previous high of four sets that occurred way back in 1958, Stehn said. "This is a special year for the birds."
Fall migration begins in September, and they usually migrate in small flocks of ten or less. They arrive at Aransas between late October and mid December where they will spend approximately six months. In April, the birds journey back to Canada.
In addition to the world's only naturally migrating flock of whooping cranes that travel annually between Canada and the Texas coast there are 145 birds in captivity. There is also a non migratory flock of 53 birds that has been established in central Florida. A second migratory flock of 83 birds has also been established that journey between Wisconsin and Florida. These additional flocks are important in case a disease outbreak or other disaster strikes the Texas flock.
"As positive as the recovery program has been, there are certainly some long term threats including sea level rise, climate change and development of the Texas coast," Stehn said. Decreased freshwater inflows into the fragile estuaries the cranes frequent and continued loss of marsh habitat are two prominent dangers to continued recovery.
"If we are going to have room for the population to continue to grow we are going to need more land probably thru conservation easements with private landowners," Stehn explained.
When whooping cranes arrive on the Texas coast after their perilous migration across the nation they divide up into family territories. Many of these territories straddle the intracoastal and a barge accident or oil spill could be disastrous. They eat minnows, crabs clams, frogs, insects, small rodents and berries. While much of their time is spent in marshes they also utilize upland areas.
As the whooping crane population slowly expands and their wintering territory enlarges then their chances of survival increase. Someday, they may even begin to winter further south along the Texas coast and that lends even more incentive to protecting the Laguna Madre and adjacent ranch land.
If you are interested in seeing whooping cranes then there are several tourist boats that work out of the Rockport area. If you are a photographer and want to perhaps get a little closer to the birds then Larry Ditto leads a limited number of photo trips to the area. The best way to contact Larry is thru his website Larry Ditto Nature Photography. "I try to charter with local guides who know the area well. We go on a small boat with a small group of just photographers. We are often able to float in without alarming the birds, and of course are very careful to never disturb the birds."
I recall vividly the first time I saw these majestic birds and thrilled to their call of the wild. It is a proud and haunting trumpeting made all the more poignant when you realize how close we came to losing their call forever.
Copyright 2007 Richard Moore