FAQs: How Stopping Predator Control Impacts Ground-nesting Birds
- Rob Beeson
- 3 days ago
- 3 min read
These frequently asked questions are taken from the scientific paper: Ten years on from a predator removal experiment in the English uplands: Changes in numbers of ground-nesting birds and predators.
Why are generalist predator populations a concern in the UK?
How did the original predator removal experiment impact ground-nesting birds?
What happened to bird and predator populations ten years after predator control stopped?
Did habitat changes contribute to the observed bird declines?
How do the bird population trends in the study area compare to wider UK trends?
What is the main conclusion of the study regarding the rapid declines in ground-nesting birds?
What is the central issue addressed in this study?
The study investigates the impact of predator populations, specifically generalist mesopredators like Carrion Crows and Red Foxes, on the abundance of ground-nesting birds in the English uplands. It examines the changes in bird and predator numbers ten years after the cessation of a predator removal experiment.
Why are generalist predator populations a concern in the UK?
Generalist predator populations, including Carrion Crows and Red Foxes, have significantly increased in the UK over recent decades. The study suggests this is linked to factors like intensified agriculture and non-native woodland providing refuge. High densities of these mesopredators are considered among the highest in European countries.
How did the original predator removal experiment impact ground-nesting birds?
The initial predator removal experiment (2000-2008) in North Northumberland demonstrated a substantial positive impact on ground-nesting birds. Legal removal of predators, primarily Red Fox and Carrion Crow, resulted in a three-fold improvement in the breeding success of ground-nesting species and subsequent increases in their abundance on the controlled plots.
What happened to bird and predator populations ten years after predator control stopped?
Ten years after predator control ceased, there were dramatic changes. Abundance of Carrion Crow and Red Fox (measured by scat index) significantly increased by 78% and 127% respectively. Concurrently, there were significant declines in several ground-nesting bird species including:
Golden Plover (-81%)
Snipe (-76%)
Lapwing (-58%)
Curlew (-24%)
Red Grouse (-74%)
Grey Partridge and Black Grouse became locally extinct in the study plots
Protected avian predators like Buzzards and Ravens showed non-significant increases, consistent with wider UK trends.
Did habitat changes contribute to the observed bird declines?
The study monitored habitat composition and management during and after the experiment. Measures of dominant vegetation (Heather, Purple Moor Grass) and their heights showed no significant difference between the experimental period and the resurvey ten years later. This suggests that habitat changes were likely not the primary driver of the observed bird declines in the study area.
How do the bird population trends in the study area compare to wider UK trends?
The observed declines in ground-nesting birds in the study area broadly mirror UK-wide trends for the same species as recorded by Breeding Bird Surveys. This consistency suggests that reductions in predator management, or a combination of factors including habitat changes, may be widespread in UK uplands and contributing to these declines.
What are the potential management strategies discussed to address the decline of ground-nesting birds?
The study discusses several approaches including:
Continued Lethal Predator Control: The findings support the idea that lethal control of legally controllable predators, potentially at landscape scales, is essential in the short to medium term to help prevent further declines in vulnerable ground-nesting birds.
Landscape Reconfiguration: Long-term restructuring of habitat to be less predator-friendly, such as the removal of non-native forests, is suggested.
What is the main conclusion of the study regarding the rapid declines in ground-nesting birds?
The study concludes that the rapid declines and local extinctions of ground-nesting birds were strongly associated with the recovery of legally controllable predators following the cessation of their removal, and likely also influenced by increased abundance of protected predators. It emphasizes that continued lethal predator control may be necessary to support these bird populations while exploring longer-term solutions like landscape-scale habitat changes.
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