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Refuge notebook: The lives of trumpeter swans revealed

Posted: May 30, 2013 - 5:11pm  |  Updated: June 4, 2013 - 4:42pm
Photo by Ted Bailey Former refuge pilot Bob Richey flew most of the early trumpeter swan surveys on the Kenai National Wildlife Refuge in the 1960s and helped neck-band the first swans on the refuge in 1972 with Dr. Bill Sladen from The John Hopkins University.  He is shown here in 1984 with a trumpeter swan to which a drop-off, radio transmitter harness was just attached.
Photo by Ted Bailey Former refuge pilot Bob Richey flew most of the early trumpeter swan surveys on the Kenai National Wildlife Refuge in the 1960s and helped neck-band the first swans on the refuge in 1972 with Dr. Bill Sladen from The John Hopkins University. He is shown here in 1984 with a trumpeter swan to which a drop-off, radio transmitter harness was just attached.

We on the Kenai Peninsula are fortunate to still hear the calls and witness the majestic elegance of North America’s largest waterfowl, the trumpeter swan. Adult males can weigh close to thirty pounds and reach over five feet in length. Once considered endangered because of their decimation in the Lower 48 , they were delisted in 1968 when trumpeter swan recovery began there and trumpeters were found nesting in Alaska.

Although trumpeter swans have undoubtedly been breeding on the Kenai Peninsula for thousands of years, it was not until the 1950s that the first attempts were made to document their status here and other areas of Alaska. The first systematic aerial survey of trumpeter swans began on the former Kenai National Moose Range in 1957 when refuge manager Dave Spencer reported 18-20 pairs of nesting swans north of the Kenai River. In 1964, refuge manager Will Troyer expanded the surveys to include detailed observations of swan behavior and movements. These and other findings were published in the 1971 Wildlife Monograph: The Trumpeter Swan in Alaska.

In the 1960s, a few swans were fitted with small metal leg bands to determine their migration routes and wintering areas. Instrumental in these early studies was Dr. William J. L. Sladen, from John Hopkins University, who was also studying the smaller tundra swans (formerly called whistling swans) in Alaska. Because only one percent of metal-banded swans were re-sighted on their wintering grounds, Dr. Sladen began using more visible, color-coded plastic neck and leg bands which increased re-sightings to 25 percent. Cygnets are captured before they can fly and adults are captured when they are flightless during their annual feather molt.

Beginning in 1972, refuge pilot Bob Richey helped capture and place these new bands on refuge trumpeter swans. Bob also flew most of the swan surveys on the refuge in the 1960s and early 1970s, as well as many other wildlife surveys, accumulating over 6,000 hours of flight time on the refuge alone, plus more hours flying elsewhere in Alaska before he retired.

My contribution to the refuge’s trumpeter swan surveys and studies began in 1977. My first aerial swan survey was the annual late brood survey with refuge pilot Vern Berns, now deceased. To map swan locations, I eventually memorized the hundreds of named and unnamed lakes, ponds and streams that were used by trumpeter swans on the refuge; today’s pilots and biologists rely on GPS.

From the late 1970s through the 1990s, I flew many swan surveys and helped band swans with U.S. Fish and Wildlife Service pilots Bob Richey, Bob Delaney, Wally Soroka, Bill Larned, Rick Johnston and Rick Ernst. In July 1979 my colleague Ed Bangs and I captured the well-recognized female swan 09VY and replaced the damaged neck band first placed on her in August 1972 by Bob Richey. At eight years old, she was the oldest swan then known on the refuge although wild trumpeters are known to live at least 24 years. From 1982 through 1986 we also attached small radio transmitters to determine nesting and cygnet-rearing habitat requirements and movement patterns on the refuge and the routes they took during fall migration. These studies showed the importance of the relatively few lakes used for nesting on the refuge, although many nesting swans also used up to seven nearby lakes and small ponds to successfully rear their cygnets. Swan families, especially if disturbed, sometimes walked their flightless cygnets overland up to 1.4 miles to reach another water body, exposing them to increased predation.

In the fall, marked swans flew over 26 miles to staging areas on the peninsula before migration; two important staging areas we discovered were the lower Moose River and Watson Lake. Migrating swans then flew to Chickaloon Flats, turned abruptly east, crossed the Kenai Mountains near Portage Glacier, and entered Prince William Sound where some flew directly across, stopping briefly on Hinchinbrook Island, before flying to Cordova and the Copper River Delta. Our pilot/biologist colleagues in southeast Alaska subsequently located our marked swans further down the coast at Cape Suckling, Icy Bay, Malaspina Glacier, Yakutat, Prince of Wales Island, and Ketchikan and at Burlington, Washington.

Depending on winter severity, Kenai Peninsula swans overwinter along the coast of southeast Alaska, British Columbia and in the Skagit River area of northwestern Washington. I visited the Skagit River in the 1980s and was amazed at the differences in winter habitat used by swans compared to their rather pristine and remote nesting habitat here on the refuge. Surrounded by development, roads and farms, their wintering areas also contained decades of accumulated lead shot which, when ingested, caused death by lead poisoning. Although lead shot has since been banned for waterfowl hunting, lead pellets remain in the soil. Over 1,000 trumpeter and tundra swans have died over the years in wintering areas in British Columbia and Washington. One report revealed that 92 percent of swan mortalities were trumpeter swans and 70 percent were due to lead poisoning. Sixty percent of gizzards from dead swans contained more than 20 lead pellets each.

Despite the mortality from lead poisoning in the Pacific Northwest, the North American trumpeter swan population expanded from 3,722 in 1968 to 46,225 in 2010. Alaska populations grew from 2,847 to 25,347 during the same period, but may now be approaching the carrying capacity of its forested wetland habitat. Global warming is believed to have allowed trumpeter swans to slowly expand their range northward since 1968 by providing more swan habitat and longer growing seasons.

On the Kenai Peninsula, as refuge biologist John Morton reported in 2011, the trumpeter swan population remained around 30 nesting pairs from 1957 through 1984, but then increased to more than 50 pairs only after aircraft were prohibited from landing on refuge lakes used by nesting trumpeters, tent camps were removed from several refuge lakes previously used by nesting swans, and a spring staging area was protected at the Skilak Lake outlet. Nesting trumpeters do not tolerate repeated human disturbances well. Most lakes outside the refuge boundary that were once used by nesting swans in the 1950s and 1960s have since been abandoned because of the construction of roads and residences along lakeshores and associated disturbances. Aside from a handful of private lakes, the Kenai National Wildlife Refuge provides the only remaining nesting habitat for the magnificent trumpeter swan on the Kenai Peninsula — they have nowhere left on the Peninsula to go.

Ted Bailey is a retired Kenai National Wildlife Refuge wildlife biologist who has lived on the Kenai Peninsula for over 37 years. He maintains a keen interest in the Kenai Peninsula’s wildlife and natural history. You can find more information about the refuge at http://kenai.fws.gov or http://www.facebook.com/kenainationalwildliferefuge.

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