Florida weather station detects migrating birds on weather radar

The birds were migrating from South America

The colours on the U.S. National Weather Service radar in Key West, Florida was a mix of blue, green and yellow.

The blue was rain. The green and yellow was a huge swarm of birds migrating from South America over Florida.

The event on Monday was unusual because flocks of birds can fly thousands of kilometres undetected.

The birds were picked up on radar because of atmospheric conditions. It took hours for the flock to fly over the weather station.

Meteorologists said the group measured 145 km in radius.

NWS meteorologist Kate Lenninger said the birds landed in Florida just before sunrise Monday, having started in Cuba the day before.

Banner courtesy National Weather Service