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National Geographic : 2002 Aug
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INSECT WORLD Monarchs: The Body Count Massive winterkill raisesestimate of living butterflies Victims of a January storm, monarch butterflies car pet the ground west of Mexico City (above). But from death comes understanding for researcher Lincoln Brower of Sweet Briar College. For 25 years he has trekked to the monarchs' winter homes-fir forests in cen tral Mexico-after they migrate from points north. Winter storm mortality isn't uncommon, but this year it was catastrophic: 273 million monarchs perished in two colonies, Brower figures. That raised a statistical problem. In 1977 Brower calculated that Mexico's overwintering mon archs totaled roughly 100 mil lion. But after counting the dead butterflies and extrapolating to arrive at a more accurate tally of the living, he now thinks the number of migrant monarchs in Mexico each year may be closer to half a billion-a figure Brower calls staggering. CONSE RVAT ION Aa decade ago. John Kasbohm of SPan ers ising the U.S. Fish and Wildlife Ser Panthiers: 80, Rising vice thinks crossbreeding with a Texas subspecies in 1995 may be N ew genes may offer hope reducing genetic defects. Roadkill for the Florida panther, remains a problem, but under A recent census tallied passes built for wildlife and miles some 80 cats in southwestern of fencing have sharply reduced Florida, compared with 30 to 50 the toll along some highways. 0, OR 0 Find links and resources selected by our Research Division at nationalgeo graphic.com/ngm/resources/0208. ALMANAC August Summer in the Canadian Arctic: Hundreds of narwhals laze in the fiords and bays of Lancaster Sound, where they feed on abundant squid and flatfish. The small, tusked marine mammals also attract the attention of killer whales, which drive them into the shallows for a bloody feast. ARTBYDONBREEDEN ARTBYDONBREEDEN NATIONAL GEOGRAPHIC * AUGUST 2002
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