(Lafferty et al. , 2006; Wilson & Colwell, 2010). Using signs alone to warn people of nesting shorebirds reduced the probability that hooded plover eggs were crushed (Weston et al. , 2012). Often, multiple specific measures are used in combination to reduce disturbance. In the north- east USA, a combination of signs, access restrictions, viewing platforms, patrols and penalties for infractions drastically reduced disturbance of shorebirds (Burger et al. , 2004). In Portugal, Little Tern Sterna albifrons nesting success was improved by a combination of signage and wardening nesting areas during weekends at peak disturbance times (Medeiros et al. , 2007). In New Jersey, USA, a combination of signage and education improved the reproductive success of Common Terns Sterna hirundo (Burger & Leonard, 2000). In Namibia, a combination of information boards, barriers, limiting quad bikers to one designated route and handing out information sheets to recreational users increased the overall number of chicks hatching from a Damara Tern Sterna balaenarum colony (Braby et al. , 2009) .
Excluding predators can increase nesting success (e.g. Dinsmore et al. , 2014), however, the use of exclusionary fences may also lead birds to abandon their nests (Vaske et al. , 1994).
Harvesting seafood from tidal flats can disturb roosting and foraging shorebirds. Here, people are searching for invertebrates on the tidal flats of Sonadia Island, Cox’s Bazar, Bangladesh [Credit: Sayam Chowdhury].
3. Factors that can affect outcomes
Bird species: Tolerance to disturbance varies between shorebird species. For example, one study found Bar-tailed Godwits Limosa lapponica to be more susceptible to noise disturbance than other shorebirds (van der Kolk et al. , 2020). Species- and disturbance- specific ‘flight initiation distances’ can be used to inform positioning of measures such as signs, fences and viewing platforms (Livezey et al. , 2016). Type of disturbance: The costs and benefits of human presence on shorebirds will depend on factors such as the proximity, frequency and intensity of any disturbance. The specific method used to manage disturbance will need to be tailored to the type of disturbance. For example, signs adjacent to nests will not reduce disturbance from drone pilots operating
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