It’s time for motorists on northern New England’s roads to take extra care.

The annual migration of moose from the interior forests is on, and May is the month when police in Maine, New Hampshire and Vermont see an increase in the number of vehicle collisions with the animals.

Moose have largely subsisted on twigs and small branches over the winter, and they are lured out to roadways, where nutrients are plentiful in the spring.

The blacktop warms up before many other areas and plants spring up by roadsides and in the surrounding marshy areas early in the season, said Maine Warden Service spokesman Mark Latti.

The snow-melting road salt is another attraction, Latti said. Some of the plants have absorbed the salt, but the moose also eat the salt left over from the winter.

“You’ll see, sometimes, moose on their knees. It’s really a strange sight … their rumps are in the air and they’re licking the road,” Latti said.

Crashes with moose can be deadly, but there have been no such fatal accidents so far this year in any of the three states.

But Vermont State Police said that last month a Maine man was treated for injuries after his minivan collided with a moose near Williamstown. The minivan caught fire after the collision, but the driver was able to escape the burning vehicle.

Large adult moose weigh up to 1,500 pounds and can be more than 9 feet tall. Since the bulk of their weight is above the hood level of most cars, their bodies often come crashing through windshields in collisions.

The moose’s dark color makes them hard for drivers to see at night. And because moose are so tall, their eyes are too high up to catch the reflection of oncoming headlights.

According to the Maine Interagency Work Group on Wildlife/Motor Vehicle Collisions, the number of highway accidents involving moose jumps dramatically in May and peaks in June. Between 1996 and 1998, there were a total of 72 accidents in April, 331 in May and 426 in June.

Vermont and New Hampshire also see more crashes in May.

“May, out of the 12 months, is the highest month as far as motor vehicle collisions with moose,” said Cedric Alexander, a district wildlife biologist in St. Johnsbury, Vt., and chairman of the moose management team.

Alexander is aware of at least 10 human fatalities caused by moose collisions in Vermont since 1985.

Maine had one in 2001 and three in 2000, said Stephen McCausland, spokesman for the Maine Public Safety Department.

“It has been relatively safe in the last couple of years, and that is probably a bad omen for this year,” he said. “It has not been in the news, and people are not thinking about it. And many times that is when trouble happens.”

New Hampshire has about 200 to 250 moose-car collisions each year, according to Eric Aldrich, spokesman for the New Hampshire Fish and Game Department.

Moose are also wandering the roads in spring as mothers send their yearlings off to find their own territories and forage for themselves, Aldrich said.

“Moose are getting kicked out for the first time by their mothers,” Aldrich said. “They’re on their own and they’re wandering all over the place. They’re not as experienced – they’re more likely to end up in oddball situations.”

Dusk is one of the worst times of day for accidents, he warned. But no one anywhere is guaranteed a moose-free drive.

“Moose can be anywhere in the state, not just where you see moose crossing signs,” Aldrich said. “It could be on I-93 near Salem, it could be the road you take to the dump.”