We have been fortunate this winter to have an ermine periodically come by our house. I first saw its tracks in the snow on our porch and around our woodshed in late November but did not actually see it until Christmas day. Early that morning after preparing giblets for our turkey dressing, I hung the remains of a turkey neck from a string on a nearby tree limb so that chickadees could feed on the remaining tissue lodged amongst the vertebrae. Then just before we sat down to eat our Christmas dinner we saw the ermine repeatedly leaping from a tree limb to reach the turkey neck; it was a constant blur of activity. We didn't see it again until New Year's Eve when I photographed it and saw it several more times later, most recently on Jan. 20.
Ermine, also known as short-tailed weasels (scientific name Mustela erminea), have very elongated bodies with short fur, legs, and ears and no apparent shoulders or hips. These are adaptations for flexible movement in highly cramped spaces below the ground and beneath snow where ermine hunt small mammals. Its unusual body shape helps them maneuver in constricted spaces. Weasels are so flexible they can turn 180 degrees in a burrow and actually pass their hindquarter going into a burrow as their head and shoulders are coming out. They are also extremely strong for their small size and can readily carry prey equal to their own weight.
But their super-slender shape also has disadvantages: their long, thin body rapidly looses heat, which means they must maintain a high metabolism and constantly catch prey to survive. Furthermore, they do not store body fat because it would interfere with their flexibility while hunting voles and mice in cramped spaces. Thus ermine are almost always on the move. Above ground, ermine hunt by coursing back and forth, zigzagging from one place to the next where small mammals may be hiding under debris or beneath the ground or snow. Watching one or tracking one reveals their boundless energy. To follow the travel route of an ermine that is hunting in the snow is extremely difficult because of the multitude of tracks it leaves going in different directions.
Ermine are one of three species of weasels in North America; all are of the mammal genus Mustela. The name "Mustela" is derived from two Latin words: "Mus" for mouse and "telum" for spear; thus weasels are "mouse-spears" -- an appropriate name since all weasels prey mainly on small mammals, especially voles and mice. Ermine are circumpolar because they are found throughout northern North America, Europe and Asia; they are known as stoats in Europe. There are two other species of weasels in North America; the tiny pigmy or least weasel (Mustela nivalis), another circumpolar species, and the large long-tailed weasel (Mustela frenata) found only in the central part of North America south into northwestern South America.
Ermine are common on the Kenai Peninsula especially when voles are abundant, but the smaller least weasel is rare. In northern areas the fur on both species turns white in the winter to help conceal them from above-ground predators especially hawks and owls. But they are still vulnerable. While snow-tracking an ermine at the edge of a bog on Jan. 17, I saw where a raptor -- probably a goshawk -- repeatedly attempted to capture an ermine and left wing, talon and tail marks in the snow among a myriad of running and dodging ermine tracks. But it appeared that the ermine escaped by tunneling deep under the snow because I found no blood or fur that indicated the raptor was successful.
New Zealand biologist Carolyn King, who has extensively studied weasels and has written the definitive book on them, refers to weasels as "hair trigger moustraps with teeth." She wrote that Native North Americans used ermine skins to trim the ceremonial bonnets and costumes of their chiefs. The white pelts of ermine (with black tips on the tail) were also reserved for nobility in medieval Europe and English judges traditionally wore ermine fur. In 1937, 50,000 ermine skins were reportedly sent from Canada to the United Kingdom to make robes used during the coronation of King George VI. Consider yourself fortunate this winter if you see one of these beautiful creatures esteemed by chiefs and nobility and even more fortunate if you are able to photograph one of these bundles of boundless energy.
Ted Bailey is a retired Kenai National Wildlife Refuge wildlife biologist who has lived on the Kenai Peninsula for over 33 years. He maintains a keen interest in the Kenai Peninsula's wildlife and natural history.
Previous Refuge Notebook articles can be viewed on the Refuge Web site http://kenai.fws.gov/. You can check on new bird arrivals or report your bird sighting on the Kenai National Wildlife Refuge Birding Hotline at 907-262-2300.
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