To all snowbirds basking in the desert sun: Minnesota needs you to fly back home by April 1.

Notices sent out last fall asked snowbirds to return in time for the 2010 census. Lest they forget, the message is also being delivered to points south. Three volunteers, each headed for a different state, are bringing fliers to post at snowbird destinations, to spread the word one last time.

This year, there's more than state pride on the line.

"If even a fraction of Minnesotans miss this opportunity, we could easily be left with only seven representatives in the U.S. House of Representatives," State Demographer Tom Gillaspy said in a news release. The State Demographic Center estimates that fewer than 3,000 people could be critical for Minnesota to retain its eighth House member.

The problem is that you can't simply fill out the form you get at your winter home.

With census forms geo-coded to each address, filling out a form in Arizona or wherever you may be staying will count toward that state, not Minnesota. If you are not home before April 1, you will need to obtain a replacement form when you get back. You can get these at questionnaire assistance centers open from March 19 through April 19. They are located at DMV offices, libraries, city halls and community centers statewide, said Barbara Ronningen of the Demographic Center.

Will Craig, associate director of the Center for Urban and Regional Affairs at the University of Minnesota, remains confident that Minnesota snowbirds will do their part. "It's not like people go off to Arizona and forget they're Minnesotan," he said. "They keep the ties."

WHO'S A SNOWBIRD?

Retirees who leave for five or more weeks at a time, starting in November. The average age is just under 70, Craig said. "At some point they stop going. After 75 it's sort of like nobody's going anymore," he said.

They account for about 10 percent of the state's retired population, Craig said. That's more than 65,000 people.

WHERE DO THEY GO?

One-third: Arizona.

One-third: California and Florida combined.

14 percent: Texas.

The rest: Scattered randomly across the Sun Belt.

WHAT'S AT STAKE?

"Each resident who fills out a census form is responsible for bringing as much as $14,000 back to the state over 10 years out of the $400 billion the federal government distributes based on census numbers," said Ryan Dolan, campaign coordinator of the 2010 census.

Carolyn Mann is a University of Minnesota student reporter on assignment for the Star Tribune.