ST. PAUL, Minn. (AP) -- Transmitter data confirm the unusually warm spring is bringing loons back to Minnesota almost three weeks earlier than usual.

The Department of Natural Resources says at least six of 29 loons tagged with satellite transmitters have returned to their breeding lakes as of last Wednesday. The earliest arrival returned to Big Mantrap Lake in northern Minnesota on March 29.

Most left Minnesota in October and spent about a month on Lake Michigan before departing for the Gulf of Mexico in early December.

Researchers are still studying whether the 2010 Gulf oil spill has affected Minnesota's state bird. Young loons that fly south spend two summers on the Gulf Coast before returning north. It's not known how many died because of the spill and how many just haven't come back yet.