Causes of change

There is good evidence to suggest that Redshank decline is related to changes in habitat management, in particular drainage and agricultural intensification. Where birds still nest in wet meadows, a suggested solution includes manipulating water levels, reducing grazing and suspending agricultural operations during the nesting period.

Further information on causes of change

Agricultural intensification has been associated with the decrease of several grassland breeding wader species (Wilson et al. 2004, 2005a). Conversion of grassland to arable cultivation (Robinson & Sutherland 2002) and grassland intensification, such as reseeding, use of artificial fertilizers, switch from hay to silage and lowering of water levels all decrease the suitability of habitat for breeding waders (Green & Robins 1993). Grass grown for silage presents a tall, dense and uniform sward in spring that is cut earlier than hay meadows, incurring additional losses of nests and chicks (Beintema & Muskens 1987, Kruk et al. 1996, Vickery et al. 2001, Atkinson et al. 2004). Grassland intensification and land drainage have resulted in dry ground with dense, homogenous swards which are rarely used by breeding waders (Smart et al. 2006). High stocking densities bring associated risks of trampling of nests and chicks (Beintema & Muskens 1987, Green 1988), though cattle produce taller swards than sheep, hence providing a better breeding habitat for Redshank (Smart et al. 2006). Studies of godwits and Lapwing have suggested that deteriorating breeding habitat makes wader nests and chicks particularly vulnerable to predators (Bolton et al. 2007, Teunissen et al. 2008, Schekkerman et al. 2009), though predation on Redshank eggs and chicks by native predators remains to be studied. However, in the Uists, where a minor population increase has occurred (Calladine et al. 2015), clutch survival is significantly lower in areas where introduced Hedgehogs Erinaceus europaeus are more abundant, and cameras showed that levels of nest predation by Hedgehogs are high in these areas (Calladine et al. 2017).

An intensive field study in Norfolk showed that density of breeding Redshank within coastal and inland grazing marshes was associated with wet features within each field: nest-site selection was associated with clumps of tall vegetation and hatching success was higher in areas of penetrable soil where this species prefers to feed (Smart et al. 2006). On coastal grassland, shallow wet features and vegetation structure have been shown to be important to several species of breeding waders (Vickery et al. 1997, Milsom et al. 2000, 2002, Eglington et al. 2008). Milsom et al. (2002) showed that adult Redshanks prefer to feed in wet rills than dry ones or on open grassland. Soil invertebrates are more accessible when water levels are just below the soil surface (Ausden et al. 2001).

In lowland England, where agricultural intensification has been intense and widespread, Redshank and other grassland-breeding waders have become restricted to areas managed as nature reserves or under agri-environment schemes (AES) (Wilson et al. 2004, 2007, Ausden & Hirons 2002). In Scotland, land use changes leading to a reduction in spring sward height were thought to have been a likely contributory factor to a 25-year decline on mixed farmland in Perthshire (Bell & Calladine 2017).

A study in Estonia found that breeding sites were preferentially located further away from woodland and suggested that woodland planting may have contributed to declines there (Kaasiku et al. 2019); however, no research has been undertaken to investigate whether planting may have contributed to declines in the UK.

Information about conservation actions

The existing evidence suggests that the decline of this species is driven mainly by changes in habitat management, in particular drainage and agricultural intensification, and hence conservation actions such as the restoration of habitat, manipulating water levels, reducing grazing and delaying mowing are likely to be important for Redshank.

Much recent research has focused on the impacts of grazing on breeding success, particularly on saltmarshes, and indicates that heavy grazing is detrimental (Norris et al. 2003; Malpas et al. 2013a) and that even light grazing can reduce breeding success to near zero (Sharps, E. et al. 2015), although there is also evidence that light grazing can sometimes benefit Redshank and that nesting densities tend to be higher on lightly grazed saltmarsh (Norris et al. 2003; Sharps, E. et al. 2016). Therefore, actions to maintain lower grazing densities or time of grazing to reduce pressure during the breeding season should be considered in order to help Redshank ( Sharps, E. et al. 2017). Also in relation to grazing, Smart et al. (2006) found that cattle produce taller swards than sheep, hence providing a better breeding habitat.

A study on the Wadden Sea found that delaying mowing on saltmarshes (until August) would decrease the proportion of broods at risk (Exo et al. 2017) and hence this should also be considered at UK sites where management includes mowing. Delayed mowing of grass grown for silage would also be prudent (see Causes of Change section, above).

Elsewhere, hedgehogs are a specific problem for Redshank and other ground nesting waders on the Uists (Calladine et al. 2015) and control of this introduced non-native species may be required to conserve Redshanks here.

AES management can be successful in increasing breeding pairs of Redshank on grassland fields in Scotland (O'Brien & Wilson 2011) but agri-environment schemes are not currently delivering conservation benefits on saltmarshes and reviewing the management prescriptions to improve their effectiveness is a priority (Mason et al. 2019).

An Estonian study found that apparently suitable sites close to woodland were avoided (Kaasiku et al. 2019); hence habitat improvement should be focused on areas away from woodland and new woodlands should not be planted close to existing sites.