What effects do walkers and dogs have on the distribution and productivity of breeding European Nightjar Caprimulgus europaeus?

Abstract

Several successive studies of European Nightjars Caprimulgus europaeus (hereafter, Nightjar) on the Dorset heaths demonstrated negative effects of the proximity of urban development and associated disturbance from access on foot by people and dogs. Surrogate measures of human density and settlement, including the amount of developed land around each heathland patch and the number of houses, were significantly and negatively related to the density of Nightjars (using data from the 1992 national survey) on heathland patches, regardless of patch size. These findings prompted targeted field studies, the subject of this paper, which investigated the mechanisms and effects of recreational disturbance on breeding Nightjars. Fieldwork in 2002 focused on a suite of heathland sites representing a range of access from sites closed to the public to heaths heavily used for recreation, notably by dog walkers. Studies in 2003 concentrated on the heavily used heaths. Nests which failed were significantly closer to paths, tended to be closer to the main points of access to heaths, in areas with higher footpath density, notably of high levels of use, and in more sparsely vegetated locations. The proximate cause of nest failure was most frequently egg predation. Nest cameras, deployed in 2003 in an attempt to identify the predators of eggs or chicks, recorded just one instance of predation, that of an egg by a Carrion Crow Corvus corone , and two instances of the incubating bird being flushed by a dog, once from an egg and once from a chick, neither event preventing fledging. Flushing rate of Nightjars from the nest was associated with the height of vegetation around the nest and the extent of nest cover. The studies indicate that access disturbance interacts with environmental conditions for breeding birds. Birds flush more readily from eggs, which are highly visible when exposed, especially in areas with sparse nest cover, leaving them vulnerable to predation. Although Nightjar flushing rates were observed to be low in 2003, just one event leading to predation is enough to end that nesting attempt. Management measures are recommended to minimize the effects of walkers and their dogs on Nightjars.

The status of breeding WoodlarksLullula arboreain Britain in 2006

“…Specifically, this has provided a focus for appropriate restoration and re-creation of heathland and increasingly sympathetic management of key forests. Much of the population expansion, since 1997, has involved heathlands, rewarding several intensive programmes of management or restoration and recreation, such as the RSPB Dorset Heathland Project, in operation since 1989 (Woodrow et al 1996) and Tomorrow's Heathland Heritage (Anon 2007b Maintaining the condition of heathland, in the face of increasing pressure for development and recreation (Murison 2002, Liley & Clarke 2003, Woodfield & Langston 2004, Langston, Liley et al 2007) is imperative for the future population of Woodlarks in Britain.…”

“…Overall, the results of the next national survey will be very important, to assess whether populations were maintained or have peaked in the core areas. There are several issues that are likely to influence the population of Woodlarks in future: first, maintaining heathland habitats in the face of increased pressure from housing development and human disturbance in southern and central England will be challenging (Murison 2002, Liley & Clarke 2003, Woodfield & Langston 2004, Langston, Liley et al 2007. Second, forest management plans will need to ensure that sufficient breeding habitat is maintained in the face of changes towards continuous cover forestry.…”

Habitat correlates of Eurasian Woodcock Scolopax rusticola abundance in a declining resident population

“…Assuming this is correlated with human activity, disturbance is likely to be having a negative effect on Woodcock breeding success by increasing desertion or the risk of nest predation through more frequent flushing of adults, or directly through predation of nests by domestic pets (Langston et al 2007;Coppes et al 2017). It is sensible to assume that these factors could affect most ground-nesting species, but the effect of disturbance can be difficult to demonstrate explicitly without monitoring the fate of a large sample of nests.…”

Effect of human disturbance on long-term habitat use and breeding success of the European Nightjar, Caprimulgus europaeus

“…Previous studies of the Nightjar have been largely confined to investigations of foraging behavior (Alexander andCresswell 1990, Sierro et al 2001), habitat use (Ravenscroft 1989, Wichmann 2004, Verstraeten et al 2011, population monitoring, and population monitoring methods (Rebbeck et al 2001, Jiguet andWilliamson 2010). Several short-term studies, over one or two breeding seasons, have suggested that the recovery of Nightjar populations may be impeded by a reduction in breeding success due to increased human disturbance (Murison 2002, Liley and Clarke 2003, Langston et al 2007a. For example, Murison (2002) found that increasing total path length surrounding Nightjar nests was correlated with lower nest success and that breeding success was reduced in heavily visited sites compared with sites with little or no public access.…”

“…For example, Murison (2002) found that increasing total path length surrounding Nightjar nests was correlated with lower nest success and that breeding success was reduced in heavily visited sites compared with sites with little or no public access. Langston et al (2007a) found that Nightjar nest failure was greater near heavily used paths, and Liley and Clarke (2003) found that Nightjar density decreased with increasing density and proximity of urban development. However, there have been no long-term studies on the effect of human disturbance on Nightjar populations.…”