Cliff Roosting by Migrant Semipalmated Sandpipers, <em>Calidris pusilla</em>, at Farrier's Cove, Shepody Bay, New Brunswick

Abstract

An observation of Semipalmated Sandpipers roosting on a cliff face in Shepody Bay, New Brunswick, suggests changes from “traditional” roosting sites. Sandpipers may be altering their roosting patterns due to pressures from avian predators such as the recent, and successful, re-introduction of the Peregrine Falcon.

Effects of Extreme Tidal Events on Semipalmated Sandpiper (Calidris pusilla) Migratory Stopover in the Bay of Fundy, Canada

“…In other locations in the Bay of Fundy, Semi- palmated Sandpipers have responded to very high tides by roosting on roads or sheer cliff faces (MacKinnon et al 2008), or by taking refuge in inland fields and meadows (Wilson 1990). However, in Cobequid Bay, the loss of traditional roosting habitat during tides greater than 15 m was associated with over ocean flocking.…”

“…Tidal amplitude is only slightly lower in Minas Basin, but typically at least 1-2 m less in Chignecto Bay than in Cobequid Bay (Fisheries and Oceans Canada 2014). During periods of very high tides in these other locations around the Bay of Fundy, some alternate roost sites, such as rock outcrops, fields, and retaining walls, have been used (Wilson 1990;MacKinnon et al 2008). Our rough estimate of an extension of 3.8 to 4.3 days in duration of stay based on energetic costs of over ocean flocking thus aligns quite well with differences observed between the sites, especially with Chignecto Bay where the smaller tidal amplitude coupled with alternate roosting areas suggests less need to fly during high tide.…”

“…However, there have been instances where alternative behaviors were observed around high tide. Both the use of nontraditional roost sites (MacKinnon et al 2008) and alternative behaviors such as extended periods of flight have been noted (Dekker et al 2011). Such flight around high tide is termed "over ocean flocking" and is different from regular directional or predator avoidance flights in that it involves the use of air currents to remain airborne and thus requires less energy than regular flight (Dekker 1998;Ydenberg et al 2010).…”

Intra- and interannual regional fidelity of Semipalmated Sandpipers (Calidris pusilla) during migratory stopover in the upper Bay of Fundy, Canada

“…It was previously thought that Semipalmated Sandpipers were highly faithful to particular roosting and foraging sites within the Bay of Fundy, with only 14% of birds marked at one roost observed at other roosts less than 20 km away (Hicklin 1987). However, more recent studies have indicated that individuals may move up to 20 km daily during their stopover within a single season (Sprague et al 2008, White 2013 and may be using more nontraditional roost sites (MacKinnon et al 2008).…”

Influence of introduced peregrine falcons on the distribution of red knots within a spring staging site

“…Although peregrines may have a direct impact on some populations via increased mortality rates [ 28 – 30 ], the much greater impacts are manifest via non-lethal adjustments in behavior. Peregrines have been suggested to shape shorebird migration routes and winter distributions [ 26 , 31 , 32 ] and their presence has been implicated in observed changes in the length of stay and refueling schedules within staging sites [ 27 ], shifts in foraging sites [ 33 ] and schedules [ 34 ], altered patterns in the use of communal roosts [ 35 , 36 ] and reductions in peak body weights/wing loading [ 37 ]. The influence of peregrines on shorebird distribution and behavior has become increasingly apparent as peregrine populations throughout the globe have recovered from contaminant-induced lows [ 27 , 32 ].…”