Associations between gamebird releases and generalist predators

Abstract

1. The release of more than 40 million captive-bred pheasants and red-legged partridges in Britain annually represents a significant addition to the potential food resource base for predators and scavengers. If this extra food availability subsidizes predator populations, gamebird releases could increase predation pressure on other wild birds, affecting their populations.2. Using three extensive datasets, we examined the spatial relationships between reared and free-roaming gamebirds (pheasant Phasianus colchicus and red-legged partridge Alectoris rufa), and explored spatial and temporal associations between these gamebirds and five species of avian predator (buzzard Buteo buteo, jay Garrulus glandarius, raven Corvus corax, magpie Pica pica and hooded Corvus cornix and carrion Corvus corone crows combined) in lowland rural Britain. 3. Patterns of spatial variation in the abundance of free-roaming gamebirds across Britain appear to be largely determined by gamebird releases, over and above any effects of land use or habitat. Predominantly positive associations between gamebird abundance (both reared and free-roaming) and the abundance and inter-annual population growth rates of predators tested suggest that large-scale variation in avian predator populations may be positively affected by gamebird releases. 4. Synthesis and applications. The positive associations between large-scale gamebird release and predator populations shown here may have implications for prey populations if the releases cause increased predation pressure. If this occurs, game management could have an indirect negative impact on some prey species partially counteracting previously reported positive or benign effects of game management on wider biodiversity. Overall impacts of gamebird releases are likely to be determined by complex interactions between multiple factors, including induced predation pressure, better understanding of which would be possible with compulsory recording of releases and numbers of predators killed. Restriction of releases warrants further investigation and consideration as a potential conservation tool for wild bird populations. K E Y W O R D S corvids, game management, pheasant, predation, raptors, rear and release, red-legged partridge | 2103 Journal of Applied Ecology PRINGLE Et aL.

European bird declines: Do we need to rethink approaches to the management of abundant generalist predators?

“…Such changes may lead to predator impacts being most severe where landscapes have become fragmented and heterogeneous (Andrén, 1994). Similarly, the impact of predators may be a consequence of abundant alternative prey, such as millions of pheasants released for shooting in the UK (Lees, Newton, & Balmford, 2013; Pringle, Wilson, Calladine, & Siriwardena, 2019), or the disappearance of apex predators and the absence of trophic cascades (Crooks & Soulé, 1999; Ritchie et al., 2012). There are arguments, therefore, that the impact of increases in generalist predators could be countered through large‐scale habitat restoration, changes in land use and the reintroduction of apex predators (Ritchie et al., 2012).…”

Regional land-use and local management create scale-dependent ‘landscapes of fear’ for a common woodland bird

“…Gamebird management can also cause changes in vegetation structure that affects habitat quality for some woodland birds (Draycott et al 2008). Pringle et al (2019) showed that gamebird management can cause regional increases in avian predator abundance through the input of additional resources into the environment (prey, carrion), which could have cascading effects on prey species such as woodland birds. Our results suggest that fine-scale management of predators at the local scale (e.g.…”

Shooting pheasants for sport: What does the death of Cecil tell us?

“…Conversely, supplementary feeding for pheasants may benefit some farmland birds (Sanchez‐Garcia et al, ). Foxes, corvids and mustelids are heavily controlled by gamekeepers (Mustin et al, ) and ground‐nesting birds such as skylark Alauda arvensis and lapwing Vanellus vanellus (Bolton, Tyler, Smith, & Bamford, ) may thrive in the absence of these predators (although levels of predator control associated with game bird releases may be less influential than the positive effects on predators of providing more resources in the form of released game birds: Pringle, Wilson, Calladine, & Siriwardena, ). More controversially, buzzards Buteo buteo , protected birds of prey, may, in some instances, be killed under licence in order to protect pheasants (Parrott, ).…”