The extent to which predators limit the numbers of their prey has been the subject of debate in ecology for decades. More recently, this largely scientific debate has assumed a controversial practical and political dimension. This is because the populations of a number of different predators have increased in the UK over the last 40 years. Increasing numbers of predators have led to concerns being raised by a number of groups that increased rates of predation may be causing a reduction in prey abundance.
Although research on the ecology of predation in the context of avian prey is extensive, the extent to which predation is causally related to changes in the numbers of their avian prey is hotly debated. If changing predator numbers in the UK are impacting on the numbers of their avian prey then a series of linked ecological changes must be occurring whereby: increased numbers of predators must increase the predation rate; increased predation rates must cause a reduction in reproductive success and/or survival; and reduced reproductive success or survival must cause a reduction in prey population size. While it seems intuitive that an increase in the number of predators must result in increased predation rates, it is not inevitable that increased predation rates will result in changes in prey demography and population size.
In this study we aim to review the current state of knowledge and evaluate the existing evidence linking changes in predator populations with changes in the numbers of their avian prey.
Sponsor
This project is commissioned and funded by the charity SongBird Survival