Trumpeter Swans Hatch at Brookfield Zoo’s Indian Lake
Birds Will Be Released to Wild in Spring 2011
Guests taking a leisurely stroll around Brookfield Zoo’s tranquil Indian Lake may notice five new additions: trumpeter swan chicks. The young birds, also known as cygnets, hatched on May 28 and can be seen with their parents during regular zoo hours.
However, bird watchers who want to see them should not procrastinate, because after this Labor Day, the swans will be transported to Iowa as part of the state’s Trumpeter Swan Restoration Program. The Chicago Zoological Society, which manages the zoo, has a long history of making significant contributions to successful reintroduction programs. Since 2002, the Society has been a participant in Iowa’s program and has assisted in releasing 17 birds, not including this year’s clutch. Prior to that, the Society participated in Minnesota’s Department of Natural Resources Trumpeter Swan Restoration Project by providing 10 eggs and 28 cygnets between 1984 and 1992.
Since the adult swans at the zoo were introduced to each other in 2005, the pair has produced five successful clutches consisting of 19 chicks. The male swan was brought to Brookfield Zoo after the female lost her previous mate the year before. He is from Kellogg Bird Sanctuary, a rehabilitation center in Michigan. His left wing is slightly curled, with feathers sticking out at an unusual angle, caused by a fused fracture he sustained prior to coming to the zoo. The injury prevents him from flying, which would be critical for his survival in the wild.
Trumpeter swans were all but eliminated in the late 1800s and early 1900s due to a combination of hunting and loss of breeding habitat as the human population expanded. Since early settlement, there has been a 98 percent loss in wetlands, which is critical for swan rearing and for habitat for swan populations. By the 1930s, the majestic birds were thought to be nearly extinct. To protect this species, the U.S. Fish & Wildlife Service began captive breeding and reintroduction programs with the help of states and conservation organizations such as zoos.
The efforts are paying off as trumpeter swans continue to make an incredible recovery. For instance, Iowa’s Trumpeter Swan Restoration Program has released nearly 1,000 swans to the wild, with several pairs nesting in southern Minnesota and Wisconsin, as well as the first successful nest in Missouri in more than 140 years in 2005 and the first successful nest in over 170 years in Illinois in 2006. Over the years, many of the swans banded by Iowa’s Department of Natural Resources have been observed not only in Illinois but as far east as Virginia, south into Texas, north into Canada, and to the west in Colorado. Several of the swans donated to the program from Brookfield Zoo have been sighted. A female released in spring 2005 had a successful clutch of three chicks in 2007.
“We are thrilled to be able to participate in Iowa’s Trumpeter Swan Restoration Program,” said Tim Snyder, curator of birds for the Chicago Zoological Society. “It is extremely rewarding to be able to see the success of such a program and to know that we helped in the conservation efforts of these incredible birds, which were nearly extinct.”
There are three distinct populations of trumpeter swans in North America: Pacific Coast, Rocky Mountain, and Interior (Midwest), all of which have increased since the last status report, which was conducted in 2000 by the U.S. Fish & Wildlife Service. A new report is scheduled to be published later this year, but biologists estimate that there are approximately 50,000 trumpeter swans in North America, of which about 6,500 are found in the Midwest region.
Trumpeter swans, which mate for life, are the largest North American waterfowl, weighing up to 35 pounds (females slightly less) with up to an 8-foot wingspan. They are completely white except for a jet-black bill that dramatically contrasts with the snowy background of their feathers. Juvenile trumpeters are grayish and slightly darker on the head, with a black-trimmed pink beak.
Sometime between late March and early May, they build their nests, choosing locations close to the water, either on shore, small islands, or muskrat and beaver lodges. A male (called a cob) gathers nest material, uprooting marsh plants such as cattails, sedges, bulrushes, and horsetail, and brings them to the female (called a pen) for placement. The nest mound, which takes about two weeks to build, reaches a diameter of 6 to 12 feet and an average height of 18 inches. The same nest site may be used for several years.
Celebrating its 75th year, the Chicago Zoological Society inspires conservation leadership by connecting people with wildlife and nature. Open every day of the year, Brookfield Zoo is located off First Avenue between the Stevenson (I-55) and Eisenhower (I-290) expressways and is also accessible via the Tri-State Tollway (I-294), Metra commuter line, CTA, and PACE bus service.