Raptor health as an indicator of ecosystem health - development of novel surveillance tools for conservation

Scotland's raptors are internationally important, with large populations of five species given high level protection within EU Special Protection Areas. Some raptors nest in Scotland at higher densities and/or more productively than elsewhere. Recently, significant effort has gone into to developing the evidence base on the distribution, numbers and productivity of raptors through the formation of the Scottish Raptor Monitoring Scheme (SRMS) and its unique database which currently holds >6,000 records. The Scottish Raptor Monitoring Scheme(SRMS) is chaired by SNH, with seven other members: Joint Nature Conservation Committee (JNCC, UK statutory nature conservation adviser), Forestry Commission Scotland (FCS), Scottish Raptor Study Group (SRSG), British Trust for Ornithology (BTO), RSPB, Scottish Ornithologists' Club (SOC), and Rare Breeding Birds Panel (RBBP).

Emerging from this work is a growing concern about raptor health. Natural mortality appears to be higher in some regions than others, and there is substantial variation in development and condition of chicks which is largely unexplained by factors such as food supply. At the top of the food chain, raptors reflect changes in their habitat and food supplies. We have recent evidence of climate change influences on golden eagle productivity; wetter spring conditions in west Scotland over the last thirty years are strongly correlated with reduced productivity, possibly due to poor adult health. We suspect that infectious and non-infectious disease may account for much more of the variation in raptor mortality than previously assessed. Some mortality may be related to poor nutrition and may be density-dependent, which has key implications for managing protected areas.

We propose to have a student develop a new conservation tool for assessing the health of Scotland's raptors, using access to new and previously untapped data sources. First, one of our partners, SASA, undertakes analyses of 100-300 raptor corpses each year to detect pesticides, poisons and other chemicals. No other post mortem examinations are routinely made of these; the student will rectify this to develop a better understanding of why these birds have died, and their health status. Second, working with the 250+ active members of the Scottish Raptor Study Group, the student will collect feathers and, under licence, blood samples of chicks, to assess levels of disease, parasitism and key nutrients in these birds. Third, for the key conservation reintroduction programmes (sea eagles, red kites), the student will pool data from feather and blood samples to determine the health of 'released' compared with 'established' birds. Fourth, the student will draw together data on the raptors' prey base (notably through analysing regurgitated pellet contents, and comparing these with prey remains left in the nest) to look for regional variations, and if possible, assess the nutritional condition of some prey based on chemical analyses of the bones (in pellets and nest remains).

Although a lot of work has been published on numbers, distribution and productivity of raptors, where health of wild raptors in Scotland is concerned, we have a very limited baseline. Accordingly, we propose that the student focuses on four key objectives:

1. Provide an overview of the health of raptors found dead and submitted to SASA for chemical analyses;
2. Assess the health of raptor chicks, focusing on golden eagle and buzzard, and develop metrics for assessing this;
3. Look for regional variation in the health of raptor chicks, and factors accounting for this; and
4. Devise a tool for assessing the health of raptors, which addresses fieldwork and post mortem requirements, and provides a steer on indicators.