Far afield

Nearly 600 swans were recently tallied from an aeriel survey of Teton County. Of the 572 swans that were recorded, 99 were cygnets, or young swans.

At this time of year — the end of January, the beginning of February — birds start showing up about 7:30 a.m. The first birds are usually chickadees coming to the feeder and a magpie or two scouting for opportunities. I don’t know where the birds sleep, something I’ve always wanted to know but those two species obviously spend the night close to our house. I’d like to watch the first bird arrivals to admire their spirit, their endurance and even their grooming. Awake, refreshed and coiffed; a lot more ready to face the day than I am.

When birds arrive near the bird feeder or on the bird feeder, when branches are being tossed around by wind and the bird feeder is also in motion, I often reflect on the marvelous control that birds have to break their flight to land and perch apparently unerringly. They can land on branches, land on metal objects, land on wood or plastic, and that brings us to a little bit about how perching birds work.

Here’s another bird inquiry that calls for some answer: How can birds hang on, even when asleep, to perch that may be moving about erratically and violently (viz, a tree branch in heavy gusty wind)?

To get at this, let’s consider first what are considered to be perching birds. Of course, to some extend, all birds perch in one manner or another, but a “perching bird” has feet with four separate toes, three facing forward and one behind in opposition in an arrangement resembling the human thumb and fingers. An arrangement that’s perfect, essentially, for grasping.

The toe segments are the right lengths to allow the toes to bend snugly around even small-diameter branches. The tendons that flex the toes are tightened and thus the bird’s toes flexed around their perch just by the weight of the bird as it bends its legs. These tendons that flex the toes have, on their lower surfaces, hundreds of “tiny, firm, hobnail-like projections. When the bird perches on a branch, its weight forces the projections to mesh, rachet-wise, with hard ribs embedded on the inside surface of the adjacent tendon-sheath. As long as the weight of the bird is opposed under its toe by the branch, the tendons will remain hooked in their sheaths and the toes will retain their grip.” (Joe Carl Welty, The Life of Birds, third edition).

There are some 8,600 species of birds. As you will anticipate, foot structure varies among the major taxonomic groups. All four passerine birds’ toes join the leg at the same level of the foot. Many waterfowl and shorebirds have three forward facing toes at one level, but the hind toe is often greatly shortened and raised above the level of the foot and not in contact with the ground surface. Owls can turn their outer or fourth, toe, either forward or backward.

Kingfishers have their middle and outer toes fused for part of their length; it helps them to excavate their nest tunnels in the banks of rivers and streams. Woodpeckers have two toes pointed forward, two toes pointed backward; opposing toe help woodpeckers to cling to tree trunks. Ospreys have evolved spines on the soles of their toes to help them grasp slippery fish.

And then, of course, some birds walk and some hop. But enough for now.

— Excerpt from “They do just about everything but dance,” a Far Afield column printed Feb. 21, 2007.

Field notes: Leine Stikkel noted seven crossbills, both red and yellow varieties on Jan. 16. A pair of hooded mergansers, a dipper, three swans and a kingfisher were recorded on Jan. 17.

Deb Patla spotted seven hooded mergansers at Oxbow Bend in Grand Teton National Park on Jan. 23. Adrianne Ward recorded over 50 Bohemian waxwings on the same date.

Louise Wade spotted a great horned owl on Jan. 28 in the Daisy Bush subdivision. She also noted a regular visitor at her feeder, a northern flicker. Two adult trumpeter swans and three cygnets were also seen flying over her house. She also spotted a great blue heron on Jan. 27.

Many people have been remarking on the number of swans they are seeing in Jackson this winter and no wonder. On Jan. 8, Susan Patla, nongame biologist for Wyoming Game and Fish Department, conducted an aerial survey to count trumpeter swans in Teton County. She surveyed wetland habitat south of Grand Teton National Park to the Lincoln County line.

The grand total observed was 572 swans or 473 adults and 99 cygnets. Cygnets retain their gray, juvenal plumage throughout the first year so can be distinguished even from the air.

The swans were spread out as there have been plenty of open water habitat to use this mild winter. Over 40 percent of the swans were seen on creeks (many of these are spring-fed) and another 34 percent on constructed ponds. The Snake River held an additional 20 percent.

Swans require quiet, open shallow water as they feed mainly on aquatic vegetation. In winter, swans often use separate locations to feed and to rest,so fly between local areas daily. It is one of great sights of winter to see these largest of North American waterfowl, fly across our snowy landscape.

Only 60 some swans live year round in the Jackson area so a majority of the wintering swans are from interior Canada. They come from as far north as the Yukon and Northwest Territories. The migrants arrive in November and will depart again by mid- to late-March. Once swans settle into winter habitat, they will not move out of the area, even if conditions become severe. Their strategy is to wait out Arctic cold blasts until temperatures warm and they have access to forage once again. The only other important wintering areas in Wyoming include the Salt River and the Green River below Fontenelle Dam.

Susan requests that people report dead or injured swans or any seen marked with colored collars or leg bands to the WGFD office: 733-2383, extension 229.

Bert Raynes writes weekly about whatever suits his fancy with a dash of news on nature. Contact him at columnists@jhnewsandguide.com.

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