WHAT'S KNOWN
• Minnesota has long been the southern extreme of North American moose range.
• Wildlife experts expected milder winters to lead to an increase in moose numbers. The opposite has happened.
• The northwestern Minnesota moose herd has declined from an estimated 4,000 in the mid-1980s to 84 last year. In the Arrowhead region, the number declined from an estimated 8,400 in 2006 to 6,500 last year.
• Non-hunting deaths, including disease, starvation and collisions with vehicles, take more than one-fifth of Minnesota moose each year, about twice the rate in the rest of North America. Reproduction doesn't cover that loss.
WHAT'S SUSPECTED
• Heat stress, in both winter and summer, has weakened moose, leaving them vulnerable to disease and parasites, malnutrition and predators.
• Moose could be gone from Minnesota by 2050.
WHAT'S PUZZLING
• Another, similar species of moose is expanding its range southward in New England, to the same latitude as Des Moines, Iowa. Despite calls to stabilize the population, expanded hunting seasons haven't stopped the growth.
• Moose are also turning up in open, agricultural North Dakota, not regarded as moose country. North Dakota state big-game biologist Bill Jensen said they seem to have a taste for sunflowers.
