VT Weekly Bird Notes: Zugunruhe!

Black-legged Kittiwake by David Cahlander

Zugunruhe!

Hold the “gesundheits” and tissues. Zugunruhe (pronounced “zoog-un-roo-huh”) literally means “restlessness to move.” It is the German word that ornithologists use to describe the urge to migrate.

Right now zugunruhe is happening all around us. An innate, physiological phenomenon, zugunruhe causes birds to become more active. In captive-held birds, species that migrate farther exhibit restlessness for more days than a short-distance migrant. Put simply, zugunruhe lasts longer for a bird that migrates to South America than a bird that has a quick flight to New Jersey.

Studies on zugunruhe conventionally focus on migratory birds. But Barbara Helm and Eberhard Gwinner (of Germany, appropriately) stepped outside the box and looked for zugunruhe in the African stonechat, a non-migratory songbird. They kept the birds in a controlled environment free of migratory cues like photoperiod (amount of daylight). Surprisingly, the stonechats experienced increased restlessness during a period that coincided with the migration season of a related European species.

Helm and Gwinner suggested that migration may not be an all-or-nothing trait, and could be lying dormant in the genes of non-migratory species, to be called on when needed. The African stonechat would have retained zugunruhe from a one-million year-old ancestor. If other non-migratory bird species have this trait, it may be come in handy in the face of environmental instability brought on by climate change.

Zugunruhe aside, for birders migration is the exclamation point at the end of the breeding season. Each weather front brings new species and flock assemblages may not be seen any other time of the year. Like foliage season, migration is the big show before the relative quiet of winter, and the birds are terrifically accommodating.

In a remarkable display of endurance, migrant birds hail from lands hundreds to thousands of miles away and pass right through our neighborhood. It’s a free parade put on every year for anyone wishing to pay attention. No need to travel far and incur the rising cost of gas; migration comes to us, thanks to zugunruhe.

Other Bird Sightings

One of the best places to observe migration is Lake Champlain. Recent highlights are sightings of adult, juvenile, and 1st-year black-legged kittiwakes. Departing from their breeding grounds as far north as the arctic and subarctic coasts, a few Kittiwakes occasionally pass through Vermont on their way to winter in the ocean as far south as Florida. Also seen were Bonaparte’s gulls (up to 125 in one day), a little gull, Caspian and common terns, and great egrets.

Least sandpipers were observed at Charlotte Town Beach and short-billed dowitchers were seen at Dead Creek. All three members of the falcon family that breed in Vermont were at the Hartland State Airport: American kestrel, merlin, and peregrine falcon.


You can explore all the birds reported last week in Vermont and add your own sightings at www.ebird.org/vins.


Rosalind Renfrew