Common swift migration
Although the common swift is occurring throughout all of Sweden, its migration and winter habitats in tropical Africa south of Sahara, are still unknown to us due to lack of ringing recoveries. By combining new technology, e.g light loggers adapted for small birds, with analyses of stable isotopes in the bird’s feathers, we hope to find out more about the Swedish commons swifts’ migratory strategies, migration routes, time of migration and winter destinations in Africa. Moreover, we want to compare the migratory behavior of various European colonies of common swifts, stretching from Italy in the south to northern Sweden, to find out how different populations are adapted to migration in terms of breeding time, migratory speed, choice of route and choice of winter habitats.
This project is financed by research grants to Susanne Åkesson from Tryggers Stiftelse, The Swedish Research Council Formas, the Swedish Research Council, and with support from CAnMove.
Less than a gram
The study depends on entirely new technology - light loggers weighting less than a gram – which have not been available in such a minute format until very recently. The light loggers are to be attached to the birds’ back and will continuously log light data, that later can be translated into information about the birds’ position over time.
Stable isotope analysis
Stable isotopes are different types of energetically stable atoms of the same chemical element, for example carbon and nitrogen, but with different number of neutrons. Since ratios of naturally occurring stable isotopes often vary in systematic ways across large geographical areas it is possible to tell where an animal has been through analyses of the occurence of stable isotopes in for example body tissue or feathers. As for the swifts, their feathers are moulted in the winter quarters and the observed isotopic signatures reflect the food eaten in different parts of Africa during their growth.
The Ecology house colony
The Ecology house in Lund has no less than 144 nestboxes incorporated in the wall of the top floor, six in each section, which can be reached from the inside of the building. A few summers ago, 7 pairs of breeding swifts moved in, and the adults will be part of the light-logger study on their migration to Africa. Next year they will hopefully return their nests, and over the years we hope that more nests will be occupied.
The nests mostly consist of feathers glued together with saliva, but also so small twigs, pieces of grass or leafs. Swifts usually return to their old nesting locations, and continue to build and improve their old nests.
Live web cameras
By video cameras we monitor breeding behavior and the development of the young in the swift nests, and also collect information on size, growth and other important breeding success data. The season for live web cameras is between June - August. Here, an adult common swift with three young.