Spatial and temporal associations between recovering populations of common ravenCorvus coraxand British upland wader populations

Abstract

1. Recovering populations of predators and scavengers have often given rise to concerns about the impact they may have on prey species. Particularly, this is the case when the prey species are of economic or conservation importance. 2. Recovery of common raven Corvus corax populations in the UK and Europe has given rise to a conflict with some stakeholders over their concerns for both the protection of livestock and the possible detrimental impact on some upland bird species, particularly ground nesting waders. This has led to demands by some land managers for licences to lethally control ravens to protect upland breeding birds. 3. We used data from broad scale surveys of distribution and abundance of upland breeding birds in the UK carried out in 1980–1993 and 2000–2002 to test whether variation in raven abundance or change in raven abundance was negatively associated with changes in abundance of five species of waders. 4. We found no significant negative spatial or temporal relationships between ravens and any of the five species of waders. However, weak (0·05 < P < 0·1) negative relationships between raven abundance and trends of curlew Numenius arquata and lapwing Vanellus vanellus may warrant further investigation. 5. Synthesis and applications. Our study found no significant negative associations between raven abundance and population changes in upland waders, and so does not provide support to justify granting of licences for the lethal control of ravens in the interest of population-level conservation of these upland wader species. However, the near significant negative associations with lapwing and curlew merit further investigation. This study emphasizes the importance of making a thorough evaluation of the evidence base before making decisions regarding predator control.