Thursday, April 10, 2014

Swan Song

From John Windau, Wildlife Communications Specialist, District Two, Findlay, Ohio

There are two species of swans native to Ohio, the tundra swan and the trumpeter swan.  Trumpeter swans are the larger of the two, both of which are native species of the United States. Although tundra swans do migrate through Ohio in the spring and fall, the trumpeter is the only native species that nests in Ohio. The adult trumpeter has snow white plumage with a black bill and feet. The young birds, or cygnets, are a sooty gray color with a pinkish colored bill and feet. The bill of a trumpeter swan may also have a red border on the lower jaw that gives the bird the appearance of wearing lipstick. The name trumpeter comes from the bird’s song, described as a resonant, deep and loud, trumpet-like call. In contrast, tundra swans, also known as whistling swans, have a much higher pitched call than trumpeter swans.
trumpeter swans and cygnets
photo from the Trumpeter Swan Society
tundra swan
Photo from the Trumpeter Swan Society

By 1900, trumpeter swans were extirpated from most of their historic range, including Ohio. In 1996, the Division of Wildlife began working on a project, in partnership with the Mississippi Flyway Council, the Cleveland Metropark Zoo, The Wilds and Ducks Unlimited, to restore trumpeter swans to Ohio. The reintroduction plan called for the release of 150 trumpeter swans in selected Ohio wetlands with a goal of at least 15 breeding pairs by 2006. This unique reintroduction was initiated to restore diversity to Ohio’s fauna and to promote wildlife enjoyment opportunities on Division of Wildlife managed wetland areas.

Today, trumpeter swans are classified as “Threatened” in Ohio and can be found in only 13 of Ohio’s 88 counties with 28 breeding pairs calling Ohio home in 2013. The Division of Wildlife’s trumpeter swan management goal is to increase its range within Ohio from the current 13 counties to 15 counties and to increase the number of breeding pairs from 28 pairs to 40 pairs within the state by 2020.

However, the chorus is not all radiant for the trumpeter swans. Another swan, ironically named the mute swan, is attempting to silence trumpeter swans in Ohio and neighboring states.
mute swan
Photo from the Trumpeter Swan Society
Mute swans are native to Eurasia and were introduced into North America during the late 1800s as decorative waterfowl. They have now established feral populations throughout North America from escaped and released birds. Mute swans were first recorded in Ohio in 1911 at Silver Lake in Akron where they were wing-clipped annually until 1934 when the birds were allowed to fly away. Mute swans are now an exotic, invasive species that threaten to displace native wetland wildlife.

Mute swans are sedentary birds that typically only migrate short distances when dictated by severe weather. Because of this, mute swans typically establish nesting territories 3 weeks earlier than trumpeter swans. Mute swans will aggressively defend their nesting territories against other native wildlife, including trumpeter swans. With only about 100,000 acres of marsh existing in Ohio, competition for limited habitat has the potential to negatively impact the success of the trumpeter swan restoration program.

In addition, mute swans feed almost exclusively on aquatic vegetation (up to 8 pounds per day!) In high densities, mute swan populations can severely reduce food availability for native waterfowl, uproot wetland plants and even destroy an entire wetland ecosystem.

Mute swans can be identified by their orange bill with a black knob at the base. Mute swans also hold their necks in an S-curve when on the water, unlike trumpeter and tundra swans. Despite their name, these birds are not actually soundless. They can make a variety of hisses, bugles and other sounds.
Photo courtesy of the Trumpeter Swan Society

Regionally, the populations of mute swans have begun to grow exponentially. The Michigan Department of Natural Resources reports that, in the last 10 years the number of mute swans has nearly tripled. Without management of mute swan populations, long-term detrimental impacts may occur to Ohio’s wetland habitats and native species like trumpeter swans.