mapping migrations
Sometime this winter, waterfowl experts from across Canada will gather for their annual "wing bee." Their task will be to sort through a small mountain of duck wings obtained from a randomly selected group of hunters, and assign the wings to piles by species, age and sex. Together with statistics from similar shindigs held in the United States, this information will provide a picture of the year's kill and will also offer hints about the ups and downs of duck populations.That may seem like a lot to learn from a heap of dried-up remains but, to Len Wassenaar of the National Water Research Institute in Saskatoon, a room full of duck wings is like an archive that can be studied for clues about each bird's life history and movements. Wassenaar and his colleague Keith Hobson of the Canadian Wildlife Service have developed a technique for reading a feather's chemistry and tracing it onto a map. The story begins with rain, which always contains a minute percentage of heavy water. That's regular H2O burdened with deuterium, a rare isotope of hydrogen. In North America, the amount of deuterium in rainfall is greatest along the Pacĩc coast and decreases to the east and south, as we
These perplexities would be easier to cope with if we knew precisely where scaups from the boreal forest go for the winter. Clark thinks the answers may lie in the scaup wings that are submitted for the annual bees. Scaups grow new feathers before leaving their breeding range, so their hydrogen signature should tell him where each bird spent the summer, be it on the plains or in the forest. By mapping this location and the spot where the duck was shot, he expects to build a detailed picture of scaup migrations and wintering grounds. The losses seem to be worst for scaups that nest in the boreal forest of northern Alberta and the southwest Northwest Territories. Is "something funny going on" in the north woods, as Clark suspects, or does the source of the problem lie farther south, along the birds' migration route or on their wintering grounds in Mexico and the U.S.? Last year, Wassenaar and Hobson used this fact to resolve a mystery that has troubled researchers for decades. Since the mid-1970s, we've known that monarch butterflies congregate for the winter in a dozen remote locations in central Mexico. Several hundred million monarchs from Eastern Canada and the U.S. settle onto the hillsides in orange drifts. But once the insects have landed, they all look the same to us, and we have no way
Some common words found in the essay are:
Northwest Territories, Clark CWS, Ontario Ohio, Savage Sometime, North America, Ontarians Ohioans, Wassenaar Hobson, Wildlife Service, Eastern Canada, Institute Saskatoon, boreal forest, wassenaar hobson, breeding stock, hydrogen signature, wintering grounds, candace savage, wintering sites, duck wings,
Approximate Word count = 879
Approximate Pages = 4 (250 words per page double spaced)
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