The Cape Bird Club

The migration of a Hobby Falcon (Falco subbuteo)
by B.-U.Meyburg, P. Howey & K. D. Fiuczynski

When using telemetry as a study method, the weight of the transmitter should not exceed 3 % of the body mass of the bird under study in order not to unduly impair the bird, and thereby falsify the study results. This still excludes many bird species from satellite telemetry studies.

On 9 August 2008 an adult female Hobby (weight 265 g) was fitted near Berlin (Germany) with a new type of transmitter which was still in the trial phase.

The transmitter is a solar transmitter weighing only 5 g with a Doppler Argos location device. After departure on migration in the second half of August, with a short rest from 6 to 13 September on the island of Elba off the west coast of Italy, migration continued at first in a southerly direction as far as North Africa.

From Libya (20 September) the bird flew in a SSW direction and reached the most westerly point of its migration route on 30 September in western Nigeria close to the border with Benin. After an initial swing of 90° towards the southeast, the falcon took a southerly course from 8 October in Cameroon. It maintained this course until reaching its main wintering area in southern Angola on 17 October. 

After more than 2 months it then continued migration in a south-easterly direction and arrived in western Zimbabwe on 29 December. From there it flew further to the east, reaching the most southerly point of its migration route between Bulawayo and Harare in central Zimbabwe on 1 January 2009. The length of the outward migration route from the nest site, excluding regional movement in Angola, was 10,065 km up to this point.

The Hobby migrated from here back to the north without a rest. This smallest and lightest satellite transmitter produced to date delivered astoundingly high numbers of good Doppler fixes.