About 1,500 mallards make Anchorage their home in the winter but biologists don’t know why.

The Alaska Department of Fish and Game has a new way to track the ducks to see where they go.

For the first time, the birds are being outfitted with radio backpacks.

“The radios also have a GPS component, so when we recapture the bird we can download the data and see where the bird went,” waterfowl biologist Mike Petrula explained.

The open water at Chester Creek provides a home for hundreds of birds as ponds around town start to freeze up.

On Thursday morning, Petrula guessed there were about 800 swimming around.

Fish and Game put up a swim-in trap near College Gate Elementary. When Petrula and wildlife Technician Kyle Smith returned there were about two dozens ducks to retrieve.

Just a few would get radio transmitters; the others would be banded with leg tags biologists use to visually track them around town.

At the Fish and Game office Petrula and Smith got to work taking down the mallards’ vital information like age and weight.

Petrula said they’ll put radios on 10 ducks for about a month, collect the data and put the transmitters onto different ones.

Part of the reason for monitoring the mallards in the winter is to give the public peace of mind.

Smith said every year the department gets calls from people concerned about the birds’ well being — especially when the temperatures drop below zero.

“People wondering why they’re staying, why they aren’t migrating. You’re always going to have some birds over winter. We seem to have a lot in town at certain spots,” Smith said. “We don’t have a whole lot of answers for them so we figured we’d start by marking some of the birds to see if the same birds are staying every year.”

Biologists hope the information they gather will help them learn more about the animals that insist on calling Alaska home year-round.

KTVA 11’s Heather Hintze can be reached via email or on Facebook and Twitter.