Friends of the Wild Whoopers …. striving to conserve wild whooping cranes

Whooping cranes are the symbol of conservation in North America. Due to excellent cooperation between the United States and Canada, this endangered species is slowly recovering from the brink of extinction. There are several ongoing efforts by government and private organizations to protect and manage whooping cranes. The U.S. Fish and Wildlife Service and the Canadian Wildlife Service are the primary governmental agencies responsible as caretakers of the Aransas-Wood Buffalo National Park population (AWBP). These cranes nest in northern Canada’s Wood Buffalo National Park and winter on the Aransas National Wildlife Refuge in Texas. It is the only remaining wild, self-sustaining migratory population of whooping cranes in the world. Friends of the Wild Whoopers (FOTWW) is one of the private groups whose mission is to assist the agencies in their role.

FOTWW’s goals and objectives are:

  1. Educating and keeping people informed about the only remaining wild, self-sustaining migratory population of whooping cranes in the world and management options to protect and increase the population.
  2. Later on, in a year or so, after increasing interest in FOTWW we will consider becoming a formal organization.
  3. During future months, make an effort to interest more people about FOTWW with emphasis on people along the Aransas-Wood Buffalo Population (AWBP) flyway, including Canada.

 

Whooping cranes are the tallest birds in North America standing at a height of approximately 5 feet. They have a 7 ½ foot wingspan measured from tip to tip.Whooping crane showing black tips of primary feathers.

          Whooping crane showing black tips of primary feathers.

They weigh only about 15 pounds even though they appear larger. Whooping cranes are almost entirely white. The body and wing feathers are a bright white, except on the tips of the outer wings. The tips of the primary feathers are black and can be observed only when their wings are outstretched as during flight.

A large red patch on the head is an obvious characteristic of the whooping crane. The red patch extends from the cheek, along the bill and over the top of the head. The red patch is made of skin and is almost featherless. Their eyes are yellow and their long legs are black. While in flight, their long necks are kept straight and their long dark legs trail behind. Whoopers are graceful flyers and picturesque dancers.

The baby chicks, known as colts, have a soft buff brown covering. When the chicks are about 40-days-of-age, cinnamon-brown feathers emerge. When they are one-year-old white adult plumage replaces the cinnamon-brown feathers. Whooping cranes live about 20-25 years in the wild.

Their preferred habitats are wetlands, marshes, mudflats, wet prairies and fields. They are omnivores and primarily eat crustaceans, small fish, amphibians, reptiles and insects. They also consume grains, marsh plants and acorns.

Their calls are loud and can carry several kilometers. They express “guard calls” for warning their partner about any potential danger. The crane pair will jointly call (“unison call”) in a very rhythmic and impressive way in the early morning , after courtship and for defending their territory. The first unison call ever recorded in the wild was taken in the Whooping Cranes’ wintering area in the in December 1999 and is documented here. http://www.craneworld.de/rufe/schreiduett.wav

Whooping-cranes-making-unison-call-at-nest-site.-photo-by-Brian-Johns.jpg

During the 1800s, whooping cranes were more abundant. Nesting was more widespread with records of nest in Iowa, Illinois, Minnesota, the Dakotas and northward through the prairie provinces of Canada, Alberta, and the Northwest Territory. Wetland drainage and clearing of areas for farming destroyed whooper habitat and hunting reduced their numbers. The only wild population that survived by the 1940s was the isolated one nesting in Canada’s Northwest Territory. This population struggled but, with improved protection and public education the slow increase of birds has continued.

The AWBP population increased from 16 individuals in 1941 to approximately 300 wild birds in September 2013. It is the only whooping crane population that maintains its numbers by rearing chicks in the wild. Efforts to increase the whooping crane population are ongoing in an experimental Eastern Population which migrates between Wisconsin and Florida. The Whooping Crane Eastern Partnership rears birds in captivity and releases them into the wild. Approximately 108 birds that they reared in captivity and released into the wild survive currently in this population. In addition, two experimental non-migratory flocks have been initiated in Florida (20 birds in 2014) and Louisiana (33 birds in 2014). An additional 162 whooping cranes are held in captivity to provide eggs to further increase the three experimental flocks and for research purposes.

Whooping-crane-current-and-former-range-and-migration-route

Whooping crane current and-former range and migration routes.

Although there has been progress in increasing the numbers of whoopers, only one population maintains its numbers by rearing chicks in the wild. This flock now contains an estimated 300 birds that nest in Wood Buffalo National Park, in the Northwest Territory of Canada. After rearing their chicks, they migrate to Aransas National Wildlife Refuge on the Gulf Coast of Texas and bordering private land where they spend the winter. It is on this wintering ground where they are especially vulnerable. A chemical or oil spill could damage or destroy their food supply. Or a hurricane could destroy their habitat and kill birds. And a growing, equally dangerous problem is diversion of river waters that flow into the crane’s habitat.

Competition is severe for the fresh water which is being used upstream for agriculture, business and for human uses in cities. Litigation is in progress to hopefully settle this problem. The steadily diminishing flow of fresh water into the bays and estuaries is making the area less productive for whooping crane foods. These foods are essential to keep the birds healthy for their 2,500-mile migration back to Canada where winter is just ending. And once there the nesting pairs need reserve energy for producing more young.

During March and April the cranes migrate from Texas back across the Great Plains and Saskatchewan to reach their nesting area in Wood Buffalo National Park. Whoopers begin pairing when 2 to 3 years of age. Their interesting courtship involves dancing together and a duet called the “unison call”. Once pairs are bonded, whooping cranes mate for life. Females begin producing eggs at age 4 and generally produce two eggs each year. Typically only one chick survives but survival of both chicks is not unusual. Whooper pairs return to the same location (“territory”) each spring. If trespasser whoopers are in their nesting area territory, they are chased away. Nesting territories may include a square mile or larger area. Chasing other cranes away ensures there will be enough food for them and their chicks. During night whoopers stand in shallow water where they are more secure from danger.

Whooping crane nesting habitat, Wood Buffalo National Park, Cana photo by Brian Johns

Whooping crane nesting habitat, Wood Buffalo National Park, Canada                         photo by Brian Johns

When the whooper pair settles in, they build a nest in a shallow wetland, often on a shallow-water island. Their large nest typically measures about 4 feet across and 8 to 18 inches high. It is assembled from plants that grow in the water (sedges, bulrush, and cattail). The two eggs are laid one to two days apart so one chick emerges before the other. Parents take turns keeping the eggs warm and they hatch in about 30 days. Chicks are called “colts” because they have long legs and appear to gallop when they run. Young colts can walk and swim short distances within a few hours after hatching and may leave the nest when a day old. They grow fast so they will be strong for the imminent migration back south. In summer, whooping cranes eat crayfish, minnows, frogs, insects, plant tubers, snails, mice, voles, and other baby birds. Colts become good fliers by the time they are 80 days of age.

During September through November the adult whoopers lead their young and retrace their migration pathway to escape harsh winters and reach the warm Texas coast. As they migrate they stop occasionally to rest and feed on agricultural and weed seeds that fell to the ground as farmers harvested their fields. When they reach the Texas coast they live in shallow marshes, bays, and tidal flats. Pairs and their young return to the same area each winter. As they did on their nesting territory, they defend their winter territory by chasing away other cranes. Winter territories normally encompass 200 to 300 acres. Winter foods are predominantly blue crabs and soft-shelled clams but include shrimp, eels, snakes, cranberries, minnows, crayfish, acorns, and roots.

Whooping crane winter habitat on Aransas NWR, Texas photo by USFWS

Individual whooping cranes may live as long as 25 years. However, they face many dangers in the wild. And while they can defend themselves and their young from many enemies, they must continuously stay on guard. Bobcats, coyotes, wolves, and golden eagles kill adult cranes. Crows, ravens and bears eat eggs and mink eat crane chicks. As they migrate, especially during storms or poor light, they occasionally crash into power lines and kill or injure themselves. In addition, they die of several types of diseases similar to all creatures.

 

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Migratory Behavior of Whooping Cranes.

mirgratory behavior of whooping cranes
Two adult Whooping Cranes in flight. ~Chuck Hardin

Probably less than a dozen persons in the past 50 years have actually witnessed the northward departure of whooping cranes (Grus Americana) from their wintering grounds on and adjacent to the Aransas National Wildlife Refuge on the Gulf Coast of Texas. Few, if any, have observed a more spectacular exodus than the junior author watched on the morning of 6 April 1966.

On this clear, sunlit day he was conducting a combination routine and spring whooping crane departure date patrol through traditional crane habitat along the east shore road of the refuge. While traveling southwesterly one-half mile north of the northeast corner of whooper feed plot No. 1, he counted 32 of the giant birds within this managed crane feeding area. When he was about 1,000 yards from the cranes, 12 of them arose and flew eastward about one mile and lit along the northwest edge of Sundown (Mullet) Bay. While watching the 12 birds alight, he heard the obstreperous calling of most or all of the remaining cranes and turned to see that these birds had taken to the air. It became apparent later that they were en route to their remote northern nesting area.

Migratory behavior

Shortly after taking to the air, the flock quickly divided into groups of 3, 3, 2, 7, and 5 birds and circled clockwise, upward, and northward in a spiraling motion. The groups of 7 and 5 birds were thought to be yearlings and non-breeders. The remaining groups were family units. The horizontal and vertical separation of the individual groups varied and was estimated to range from 400 to 1,200 feet. The diameter of the circle was judged to be one-fourth mile.

The 20 cranes left the ground at 9:00 am; 12 minutes later they were only visible as tiny airborne specks, and in a few more moments they were no longer discernible through a 7 X 50 binocular.

Winds at the time of departure were from the southeast at about 18-20 mph. Each turn of a group of cranes into the wind resulted in a gain in altitude. As the birds spiraled upward, they maintained their respective positions with no noticeable change in the size or shape of the spiral. They “whooped” continuously as they moved upward and away from the observer. At no time were the 12 birds remaining on the ground heard calling.

Departure observed

Earlier that morning Benham had observed one immature and two adult whooping cranes feeding inside whooper feeding plot No. 2, approximately one mile north of the main body of birds. They had not flown as he passed about 1,500 feet from them. On his return past this spot he noted the three cranes about 500 feet off the ground, spiraling and calling loudly in a manner similar to the previously departed birds. The time was 9:14 am. At 9:19 am, Benham lowered the binoculars to rest his eyes. When the three cranes were last seen, they appeared larger than the 20 birds at last glimpse, so it is possible constant surveillance with the binoculars would have rendered the trio visible for longer than five minutes.

It is reasonable to assume calls of the first departing cranes were heard by the later migrating family because of wind direction, audibility of the cranes’ piercing whoops, and the close distance between the two groups when the airborne flock flew over or within one-half mile or less of the family unit. We hypothesize that the exodus of the 20 birds precipitated the departure of the lone family group.

It is interesting that the first contingent of migrating cranes displayed some aerial territorialism, although they were all observed feeding side by side within the food plot a few minutes before departure.—Robert H. Shields, Bureau of Sport Fisheries and Wildlife, Portland, Oregon, and Earl L. Benham, Bureau of Sport Fisheries and Wildlife, Austwell, Texas.

[The Auk, April-June 1968, Volume 85, Number 2, Page 318]

 

 

 

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