Thursday, 27 August 2009

Hobby satellite tracking

Thought you all might be interested in this, just in from Bernd Meyburg of the WWGBP:

"Dear all,

The Eurasian Hobby is a small falcon. It breeds across Europe and Asia and is a long-distance migrant. European birds winter in Africa. More than 5,700 Hobbies have been ringed in 10 European countries, but so far there have been only two ring recoveries south of the Sahara desert. Satellite tracking using the Argos system is now an accepted technique for long distance migration studies of birds. It is generally accepted that any device we burden a bird with should weigh no more than 3% of the bird's weight if we are not to affect its behavior.

Method
The prototype of the smallest satellite transmitter (PTT) produced so far weighing just 5 g was fitted by me for the first time to an adult female Hobby (weight 265 g) on 9 August 2008 in Germany near Berlin and successfully recorded the annual migration route.
The Hobby had raised two offspring and was trapped near its eyrie using the dho-ghaza-method. This new type of solar-powered PTT was still in the trial phase and is still working (in August 2009).

Results
This smallest and lightest satellite transmitter produced to date delivered astoundingly high numbers of good Argos Doppler fixes (LC:2 and LC:3).

After leaving on migration in the second week of August, and a short rest period on the island of Elba off the west coast of Italy from 6 to 13 September, the bird flew at first in a southerly direction towards North Africa. The falcon held this course more or less until reaching its main wintering area in Southern Angola on 17 October. The migration to southern Angola took 49 days including some days on the island of Elba and one day (8 October) in Cameroon when the falcon was not moving. On average the falcon migrated 174 km per day including the days when it did not migrate.

Map
Outward migration route in 2008 up to the southernmost point in Zimbabwe not showing local movements during wintering in Angola. Copyright by B.-U. Meyburg, 2009
A summary of the results with further details has recently been presented at the 7th Conference of the European Ornithologists' Union 2009:

K.D. Fiuczynski, P. W. Howey, C. Meyburg & B.-U. Meyburg (2009):
Intercontinental migration of an Eurasian Hobby (Falco subbuteo) tracked by means of a 5g satellite transmitter. 7th Conference of the European Ornithologists' Union 2009, University of Zurich, Switzerland, 21 - 26 August 2009.

For the poster see:
http://www.raptor-research.de/pdfs/a_sp100p/a_sp140.pdf
&
http://www.Raptor-Research.de

In July and August 2009 I have been able to trap eight more adult Hobbies and mark them with even smaller solar-powered satellite tags (size: 9.3 x 30 x 16.4 mm ). From these transmitters we already received much better results during the last few weeks in the breeding area than from the first PTT in 2008. One surprising result has been an adult female which migrated 300 kms north from her breeding site after the fledging of her offspring to reach the coast of the Baltic Sea in western Poland.

Kind regards,

Bernd Meyburg

Prof. Dr. Bernd-U. Meyburg"

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