Good mole year contributed to the successful nesting of kestrels

“Bedsitters” installed on transmission line towers yielded many broods. Last year, Fingrid had bird houses installed on transmission line towers in Southern and South-Western Finland, to be used as homes by kestrels. The goal was to promote the protection of the increasingly rare kestrel by attracting it to areas where its worst enemy, the pine marten, does not dare to come. Nesting is now almost over, and preliminary calculations indicate that the bird houses installed on transmission line towers have fulfilled their purpose: dozens of young kestrels are growing in their safe bedsitters.Pertti Koskimies, ornithologist, says that kestrels have nested in different times this year, although most of the birds nested at the normal time, starting no later than the beginning of May. Since the mole population almost throughout Finland was large, there were also many kestrels with nestlings in areas preferred by these birds of prey. Kestrels also tend to have more nestlings than average in good mole years.

Farmers and seeding stand owners favour kestrels, which are also referred to as flying mole traps. A kestrel family may eat hundreds of moles and other small mammals during a nesting season. Mole hunting in the early spring increases the efficiency of this hunt, as many pregnant female moles are caught by the kestrel.

In all, kestrels inhabited nine new bird houses installed by Fingrid in Tammela, Elimäki, Ruotsinpyhtää, Anjalankoski and Luumäki. Some signs of temporary stay were also noticed in four other bird houses. Kestrels do not always leave traces – such as feathers – of their stay, but it is likely that kestrels have been aware of several of the installed bird houses. “Since male kestrels tend to stay in the same place, it is probable that the number of kestrels nesting in the transmission line towers will grow. This has been the case in all areas were new bird houses have been installed: the birds first learn to know their new habitat,” Pertti Koskimies says. 

The kestrel (Falco tinnunculus), with tapered wings and a long tail, is a member of the falcon family. It is slightly smaller than a crow, and it can be identified easily by the way in which it catches its prey: the bird hovers almost in one place against the wind over a field prowling moles. Once it notices its prey, it descends gradually and finally dives down to grab the catch. The kestrel population in Finland has declined to a fraction from that which existed half a century ago. The kestrel population has decreased for various reasons, the biggest reasons probably being environmental toxins and an increase in pine marten population. Drainage of fields and changes in the agricultural environment have also undermined the kestrel's natural hunting grounds.

Transmission line towers are extraordinary locations for bird houses, and the bird houses can only be installed by professional electricians because of safety reasons. Outsiders must not climb up transmission line towers under any circumstances. Those who ring the birds obtain special training in electrical safety.
Further information:
Pertti Koskimies, ornithologist + 358 (0)40 721 6764
Ari Levula, Maintenance Manager + 358 (0)400 648 522