Differences in migration performance between soaring and flapping flight
In this project, we will test the fundamental differences in migration performance between birds that travel mainly by soaring (raptors) or flapping flight (pigeons) or both (hobby) and between birds that travel mainly during the day (raptors, pigeons) and night (cuckoo). We will compare existing tracking data on large raptors like osprey and marsh harrier, with new data on wood pigeon (Columba palumbus), hobby (Falco subbuteo) and cuckoo (Cuculus canorus). We also plan to use 1g light-based geolocators developed by the British Antarctic Survey to record the annual journeys of individual arctic and common terns (Sterna paradisaea) and (Sterna hirundo).
In collaboration with Copenhagen University, we will also study red-backed shrike (Lanius collurio) migration. Their migration route is particularly interesting, since ringing data indicate that the shrikes for unknown reasons travel far to the east across the Arabian Peninsula during their spring migration from southern Africa to Scandinavia.
Solar panel batteries
A female Marsh Harrier is captured near her nest and a satellite transmitter is attached. Due to the solar panel the battery is re-charged during the day, which allows us to follow individual birds for several years. The current record is five years.
Different, but converging routes
A female hobby fitted with a satellite transmitter. Hobbies that were tracked from southern Sweden followed different routes towards their wintering quarters south of the equator. Interestingly, the routes of 4 different individuals converged while passing the rain forest. In Congo, the distance between routes was maximal 67 kilometres!
Preference for heights
Studying Hobbies requires climbing trees. Hobbies have an annoying preference for high and thin trees, hence the sweated face of the climber.
Wood Pigeons might not seem to be a highly interesting species to track with expensive satellite transmitters. However, given the fact that the Wood Pigeon is a daytime migrant, travelling by active flapping flight, its migratory behaviour is extremely fascinating to compare with soaring migrants such as raptor birds.
Here, an Arctic Tern is fitted with a geolocator (lightlogger) which is an archival tag capable of measuring and storing data on light levels. The data can then be used to calculate the birds latitude and longitude using a process known as light-based geolocation.
The tern is then released. Comparisons between the tern species will serve to test the demands on migratory performance associated with extremely long migrations. Next year the logger hopefully can be retrieved, so that we can reveal their migration strategies.