Migratory Restlessness

Robins are feeling restless. Ornithologists call this pre-migratory restlessness, zugunruhe. This German word comes from zug (move, migration) and unruhe (anxiety, restlessness). 

Hormones are surging. The drive to establish a territory, mate, and raise young is increasingly strong.

"Robins have an internal clock, and they know that soon it is time to start moving north. Their restlessness becomes irresistible depending on the length of day, but birds wait for the weather and temperature to be right. Robins generally follow behind the spring thaw and they wait for favorable winds. They want a tail wind. They wait for the south wind to come along and help them move north. So, knowing when to migrate involves an internal clock, a feel for temperature, and the right weather patterns that create south winds," says Cornell University biologist Martha Fischer.