The conservationists dilemma
One of the more contentious aspects of the RSPB’s work revolves around predation and particularly native species that eat birds.
Published: 18 Apr 2013
Topic: When science shows that predation is a contributory factor to the decline of already threatened species.
It is, however, a fact of life that all bird species are subject to predation. Predators have lived alongside most of their natural bird prey for thousands of years without eliminating them. However, bird populations can decline, and their numbers can be held down, where there's a high level of predation.
The RSPB's view is simple – native predators are part of the rich variety of life and are as worthy of conservation as any other species. Indeed, a key test of whether we are living sustainably is whether we are able to coexist with predators.
Emotions spill over in debates about fish-eating birds such as Cormorants and Goosanders, and when birds of prey are perceived to conflict with commercial shooting interests (such as Buzzards on Pheasants or Hen Harriers on Grouse).
The conservationists’ dilemma comes when science shows that predation is a contributory factor to the decline of already threatened species.
In 2007, the RSPB compiled a review of the impacts of predators on wild birds, drawing conclusions from the peer-reviewed published literature.
“The review concluded that generalist ground predators, such as foxes, can sometimes reduce the population levels of their prey. This is a growing worry for the conservation of populations of threatened ground-nesting birds, such as Lapwings. This conclusion accords with the RSPB’s considerable practical experience as a land manager of over 130,000 hectares in the UK. The review also concluded that the evidence to implicate predators such as Sparrowhawks in the declines of songbirds is very weak.”
A follow up review has been undertaken, reviewing the scientific literature since 2007, and broadly reinforces the conclusions. The review also raises some interesting questions around the ultimate drivers of “predation problems”. In many cases, it appears there are other factors which, if addressed, could remove or greatly reduce the predation effect.
Where evidence suggests that predation is causing a problem for species of conservation concern, the RSPB’s strong preference remains to concentrate on habitat measures that favour the prey species and make life more difficult for the predator. For example, where Lapwing productivity and numbers on nature reserves are poor, the RSPB concentrates first on improving the habitat for Lapwings (usually supported by agri-environment schemes) and on creating physical barriers such as electric fences to limit fox access. Sometimes the stakes are so high for ground nesting birds that there is no alternative to predator control – it is always a last resort.
Twenty-first century nature conservation requires the RSPB to look at both proximate and ultimate causes of declines. Any strategy that fixates on the control of native predators as the silver bullet is rejected. For some species (such as songbirds) it will be a red herring, for others it might need to be part of the solution, but on its own it will never be enough. In many ways, the impact of predation is a symptom of a broken environment, tackling the symptom doesn’t cure the disease but it does buy vital time.