Numerous offshore islands in the British Isles support dense sub-populations of Peregrine Falcons, which are often associated with seabird abundance. Peregrines have been recorded as a breeding species on Lundy for over 750 years. They are the only regular breeding raptor, with historically up to two pairs resident on the island. In 2014 and 2015, five breeding pairs were occupying nest territories on Lundy, one of the densest island breeding populations in the UK.
Few studies have investigated the factors affecting high population density with island populations of Peregrines in the British Isles. As a remote offshore island, Lundy offers the opportunity to study Peregrine population dynamics and predator-prey relationships in an area relatively free from direct human disturbance. This will give focus to understanding the ecological processes affecting the population and to compare with other island sub-populations.
This study aims to identify the factors influencing Peregrine density on Lundy and then apply that knowledge to the management of this and other island populations. Despite an increase of breeding Peregrines in urban and inland areas, coastal Peregrines in some traditional breeding areas are in decline. Determining the reasons for dense populations on islands such as Lundy could help to establish factors which may be influencing declines elsewhere in the UK.
Breeding densities of Peregrines from numerous studies show relative stability over long periods of time. The sub-population on Lundy has followed this trend with between five to six pairs occupying nest territories from 2002 to 2014. Breeding success varied significantly between 2014 and 2015 but it would be difficult to establish any reasons for this difference with such a small sample size. A long-term data set is required to observe any trends and possible links to food supply, weather and nest site quality.