The conservationist's dilemma: an update on the science, policy and practice of the impact of predators on wild birds (6)

Conservation is often about making tough decisions about when to intervene and when not to.  Sometimes - as is the case for vertebrate control - these decisions can be controversial.  In the end, decisions we take are judged by the outcomes we achieve.

Let me give you an example from a site which I last visited in November to give a fond farewell to our much-loved and charismatic colleague, Roy Taylor who passed away last year.

Since 2010, the RSPB has worked with United Utilities at Dove Stone in the north west Peak District to restore blanket bog. This cutting-edge work is a very good example of how large scale habitat restoration can bring benefits for people and nature.

Image of Dove Stone courtesy of Alan Coe (rspb-images.com)

The work aims to make the bog wetter again, blocking the gullies and re-vegetating the bare peat by planting sphagnum mosses. It’s back-breaking work and our brilliant site team could not do it without the help of local volunteers.

Healthy peat bogs lock in large amounts of carbon which is crucial in reducing the effects of climate change. They also improve drinking water quality by reducing the amount of peat being washed down into the reservoirs below.

They also benefit breeding waders such as curlew, golden plover, and dunlin. Numbers at Dove Stone have rocketed, and these increases have all been a result of the habitat restoration work. Given the geography of the area, pressure on breeding waders from predation has not been an issue and we have not needed to resort to any on-site predator control. We could have upped wader numbers quickly by doing so, but we have chosen to do the more difficult job of wider restoration, but then this has brought far wider benefits for both nature and people.

Image of curlew courtesy of Andy Hay (rspb-images.com)

However, not all places are like Dove Stone and the RSPB must look at sites on a case by case basis. Whilst non-lethal methods, are always our preferred way of doing things, they are not always practical.

As I write each year, we only carry out lethal vertebrate control on RSPB reserves when four criteria are met:

• That the seriousness of the problem has been established;
• That non-lethal measures have been assessed and found not to be practicable;
• That killing is an effective way of addressing the problem;
• That killing will not have an adverse impact on the conservation status of the target or other non-target species.

If we can satisfy ourselves of all these things, then we can be sure to make the right decision.  Our approach was recently reviewed by our trustees and I am pleased that they confirmed their support for our existing policy and practice.

I recently wrote that it was ironic that organisations like the RSPB must resort to lethal control to keep numbers of predators from impacting species of conservation concern especially when one of the reasons for the large numbers of these is perhaps the more than 40 million gamebirds that are released each year into our countryside.

It is doubly ironic that many land managers tell us that they need to do more predator control, yet it is their own game management practices that may be the cause of the claimed need.

Last year, I wrote about the review  we completed of the impact of predation on wild birds based on 81 relevant scientific papers and reports covering 908 cases where the effect of a predator on changes in the numbers of a prey species had been measured. This showed that predator numbers have increased in the UK over the last decades; that the UK has very high densities of red fox and crows compared to other European countries; that seabirds, waders and gamebirds are limited by predation whereas pigeons, raptors & owls, woodpeckers and songbirds are not limited by predation; and that there is a real need for research to understand how landscape-scale management could be used to provide longer-term sustainable solutions to reduce the numbers of generalist predators and their impacts on species of conservation concern.

We plan to do more work on this over the coming months. 

Yet, recognising that this debate is deeply polarised with strong views held on all sides, I am determined that the RSPB inputs and engages constructively based on the best available evidence. 

 In addition, the Curlew Trial Management Project killed 97 foxes and 274 crows off RSPB reserves.