The UK has the fourth largest golden eagle (Aquila chrysaetos) population in Europe (approx. 430 pairs), almost all in Scotland. Demographic monitoring of this population, primarily involving productivity and distribution of occupied and vacant territories, has been achieved by censuses every 10 years and by more spatially limited but more temporally expansive annual surveys of approx. 200 occupied territories undertaken by the Scottish Raptor Study Groups (SRSG). Whilst these surveys are important for understanding the demographics of the UK golden eagle population, they are limited because individual golden eagles cannot be confidently recognised and information on annual turnover in the breeding population is lacking.
Mouth - swabbing a golden eagle chick in 2008. © Ruth Tingay |
The most up-to-date research (Whitfield et al. 2008. A Conservation Framework for Golden Eagles: Implications for their Conservation and Management in Scotland. Click here for a copy) indicates that the Scottish population does not enjoy an overall favourable conservation status and may be close to decline. This is despite the apparent stability inferred by simple temporal comparisons of numbers of occupied territories. Persecution has been identified to be the principal national threat.
Currently, adult survival estimates are only possible using imperfect methods from classic population dynamics theory and observations of age structure of the population. This undermines our ability to monitor the population effectively. To overcome this research gap, we are using non-invasive genetic sampling to monitor the presence of individual eagles over time. With the support of the SRSG, we are collecting moulted adult feathers and mouth-swabbing golden eagle nestlings. These samples will provide DNA and thus allow us to identify individual eagles to address the following research objectives:
- Test the feasibility of using genetic markers to monitor turnover in UK golden eagles.
- Quantify site fidelity of breeding adults and hence quantify the contributions of breeding dispersal and fatality to turnover, which, in turn, will allow adult survival to be estimated.
- Contrast genetically derived measures of adult survival against those derived using indirect measures from population age structure, and re-model national and regional population dynamics.
- Examine the effects of persecution on turnover and adult survival.
WDNAS staff extract DNA from feathers. © Ruth Tingay
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Analyses of the 2007 samples has been completed (1133 feathers and 35 mouth swabs from 136 sites). 216 individual golden eagles have been sexed and genotyped. Third-year field collections in 2008 involved 72 fieldworkers and these samples are currently being processed in preparation for sending to the lab. Mouthswab trials were undertaken during 2008, to test the effect of swab type on DNA quality and quantity. These results are currently being analysed. Since the project started in 2006, over 200 unique sites have been sampled, and for many of them ‘repeat’ samples have been made over the three-year period. Our fourth year of collections (2009) are currently underway across Scotland.
This study compliments our research on golden eagle dispersal. Click here to link to our page on satellite tracking golden eagles in Scotland.
Lab work is undertaken in collaboration with Wildlife DNA Services and is funded by Natural Research Ltd. Data analysis is undertaken in collaboration with Dr Jeff Johnson, University of North Texas, USA. We thank David McLeod for his help with GIS analysis.
For further project information, please contact info@natural-research.org
YOU CAN HELP THIS PROJECT!
It costs us approx £20,000 per year to run this DNA project (including equipment, lab costs and staff time). We are a Scottish-based charity and rely upon donations to support our work.
To date, this study has received generous financial support from the Helen and Geoffrey de Freitas Charitable Trust and from the National Birds of Prey Trust. In addition, the study benefits (and is indeed reliant) on the support of voluntary SRSG members who help to collect our samples.
If you would like to make a donation to this or any of the other initiatives by Natural Research, please email ruth.tingay@natural-research.org in the first instance.
Natural Research Ltd is a charity registered in Scotland (SC030363)
Thank you
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