Spring Migration - A Scientist's Activities


March and April

Late winter and early spring is a time when scientists use helicopters and net guns to capture and collar caribou. It is also when scientists try to estimate the number of calves which have survived the winter. Sometimes these researchers use ski-equipped airplanes or helicopters to land near migrating caribou and count them as they go by, classifying them as adult females, adult males, or calves. More often, though, the scientists use a helicopter to fly low behind groups of caribou. Many more animals can be counted and classified in this manner, and much more quickly. The scientists try to finish each group of caribou as rapidly as possible so the caribou don't run too fast or too far and wear themselves out. Winter is a hard time for caribou, as food is often scarce or hard to get at, so scientists don't want to stress the caribou any more than they have to. The scientists calculate how many calves there are for every 100 cows, and compare this to the data they collected in the summer. From the difference, they can estimate calf survival through the first winter.

Caribou Scientists also try to predict how many calves will be born in the coming summer, and how healthy these new calves will be. The scientists work with local hunters to get biological specimens from caribou they've hunted for food in the spring. These spring data usually help scientists determine how well the caribou have fared over the winter and can help predict the level of calf survival during the next calving season. Pregnant cows in good shape will give birth to more vigorous calves that survive better. Pregnant cows in poor shape at the end of winter will probably still give birth, but their calves may not be able to survive the critical first year of life because of its small size.

Most fieldwork occurs early in spring migration. Afterwards, caribou scientists return to their offices to analyze data, write reports, and plan for the upcoming summer field season. They rely on the satellite collars to indicate where the herd is and how migration is progressing.

Return to A Caribou Year.