Finnish Museum of Natural History

The female pallid harrier Potku

Potku the Pallied Harrier In late June 2015 a female pallid harrier (Circus macrourus) breeding in Utajärvi, Northern Ostrobothnia was fitted with GPS/GSM transmitter. Being still a rare breeding species in our country, this marked the first occasion that a pallid harrier so tagged in Finland. The main breeding area of the pallid harrier covers the steppes of Russia and Kazakhstan. It is quite a mystery how and why the species has begun to breed in Finland.

By means of the transmitter we hope to shed light on female’s use of her breeding territory as well as, especially, her migration behaviour and overwintering areas. In recent years a growing number of pallid harriers have been observed in France and Spain between September and April. This leads one to guess whether some of the pallids breeding in Finland might opt for this migration route instead of the well-known route through the Middle East.

The transmitter was fitted by Ari-Pekka Auvinen and Julien Terraube, the latter of whom has studied pallid harriers in Kazakhstan. The transmitter is powered by a solar panel and weighs 17 grams. It was supplied by Beatriz Arroyo’s research group from the The Institute of Research in Game Resources, Madrid.

The female was named Potku which is Finnish for (a) kick. Potku is also the name of the remote village situated close to her breeding site in 2015.

Unlike in Kazakhstan, at least some of the pallid harriers breeding in Finland are philopatric (i.e. return to the same site to breed). We hope to know more about this issue when, if everything goes well, Potku returns to breed in Finland in 2016.

Joins us to follow Potku’s journey and gain an insight into the behaviour of this fascinating species!

Potku's nestlings One of Potku's fledglings in flight. Notice her bulging crop, which is full from a hazel grouse meal.

Spring migration 2017




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Text: Ari-Pekka Auvinen, photos: Ari-Pekka Auvinen, Web management: Markus Piha