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Determining the causes of Whimbrel declines in Shetland
Project objectives
- To compare breeding success and causes of breeding failure during the current period of decline with these measures during the mid-1980s when the population was increasing, and to compare breeding success between areas with and without declines.
Key dates so far
- Two summer seasons of fieldwork completed.
- Data obtained from 68 nests and 51 broods.
- Ringed 28 adults and 92 chicks (adults were colour-ringed).
- Established a new longevity record for Whimbrel (26 years) by re-sighting an adult ringed on Fetlar in 1986.
- Collated 1980s data for comparison with present study. Preliminary analyses of 2010 data undertaken.
Work planned or underway
Research began in May 2010 on the islands of Fetlar and Unst. Under licence from SNH (Whimbrel is a ‘Schedule 1’ species afforded special protection on its UK breeding grounds), nests were located and monitored until chicks hatched or the nest failed, and adults were caught and colour-ringed to allow monitoring of individual broods following hatching until they fledged or failed. This enabled breeding success to be measured, allowing comparison with the 1980s. Where possible, causes of nest failure or chick mortality were determined. Catching adults also allowed assessment of evidence for changes in measures such as body condition, and colour-ringing enables annual return rates to be assessed. Other breeding parameters including egg volume, laying dates, and chick hatching weights will be compared with data collected in the 1980s. Overall, the research will establish whether management solutions are feasible. Given that Whimbrel are at the southern edge of their breeding range in Shetland (and hence vulnerable to predicted climate change impacts), this work may also provide valuable input to policy on climate change.
Results
Analyses are ongoing, and further data will be collected in 2012.
Who to contact
Allan Perkins
Conservation Scientist
E-mail: allan.perkins@rspb.org.uk