Sanderling Plan - Western Hemisphere Shorebird Reserve Network

humans recreate on beaches, people and dogs are a potentially significant source of disturbance
to Sanderlings. Unleashed dogs (and some people) may enthusiastically chase flocks of
shorebirds; while this and other disturbances vary from periodic to continual, day after day (and
cumulatively) they translate into reduced feeding and resting time for Sanderlings. The energetic
requirements of migration are substantial, and the energy that Sanderlings expend to continually
flee from humans and dogs, combined with the simultaneous loss of opportunity for feeding or
resting, may result in reduced fitness overall for Sanderlings.
Several studies have quantified these impacts. In Plymouth Beach, Massachusetts,
vehicular traffic reduced the use of this important staging area (for sandpipers) by up to 50%,
and increased human and vehicle disturbance led to a shift in roost sites or to departure
altogether (Pfister et al. 1992). On Virginia beaches, increased human activity levels translated
into increased time spent flying (or in maintenance behaviors) and less time roosting; Sanderling
abundance declined with increasing off-road vehicle abundance (K. Forgues, unpubl. data). In
Florida during winter, as beaches became more crowded with people, Sanderlings’ foraging time
decreased, and birds moved to areas with fewer people and/or foraged more at night (Burger and
Gochfeld 1991). These and other studies (e.g., Klein et al. 1995, Roberts and Evans 1993, Burger
and Gochfeld 1991, Thomas et al. 2003) indicate that at sites where shorebirds are heavily
disturbed by humans, shorebirds spend less time foraging and resting, with potentially substantial
energetic costs. Specifically, reduced feeding and resting could result in lower energy stores (i.e.,
reduced lipid deposition), potentially interfering with the ability to migrate, with subsequent
breeding success, and possibly even with survival.
Other obvious forms of disturbance include personal motorized watercraft such as jet
skis, which have been shown to disturb roosting shorebirds in Washington (see Buchanan 2000).
However, such disturbances could be greatly reduced by employing buffer distances such as
those determined for other shorebirds (e.g., a minimum distance of between 80–100 meters from
motorized watercraft; Rodgers and Schwikert 2002). Even quiet forms of recreation such as
kayaking, kite-surfing, windsurfing, wave surfing, or fishing can cause disturbance to
Sanderlings. These activities usually require associated disruptions such as driving vehicles
along beaches, rigging or assembling equipment (poles/boards/boats) near the water,
entering/exiting the ocean, and recreating near the shoreline (either on land or in water).
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