Dramatic Declines of Semipalmated Sandpipers on their Major Wintering Areas in the Guianas, Northern South America

Morrison, R. I. Guy; Mizrahi, David; Ross, R. Kenyon; Ottema, Otte H.; Pracontal, Nyls de; Narine, Andy

doi:10.1675/063.035.0112

Cited by 48 publications

(45 citation statements)

References 19 publications

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“…We also recorded previously undescribed nonstop flights of~8000 km southbound from Churchill to Brazil. These results reinforce those of previous studies that have highlighted the Chesapeake Bay-Delmarva Peninsula region and the north coast of Brazil as supporting particularly important concentrations of Whimbrels during migration and the nonbreeding season (Morrison and Ross 1989, Rodrigues 2000, Watts et al 2008.…”

Section: Discussionsupporting

confidence: 91%

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Dichotomous strategies? The migration of Whimbrels breeding in the eastern Canadian sub-Arctic

et al. 2016

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The conservation of migratory birds requires internationally coordinated efforts that, in turn, demand an understanding of population dynamics and connectivity throughout a species' range. Whimbrels (Numenius phaeopus) are a widespread long‐distance migratory shorebird with two disparate North American breeding populations. Monitoring efforts suggest that at least one of these populations is declining, but the level of migratory connectivity linking the two populations to specific non‐breeding sites or identifiable conservation threats remains unclear. We deployed light‐level geolocators in 2012 to track the migration of Whimbrels breeding near Churchill, Manitoba, Canada. In 2013, we recovered 11 of these geolocators, yielding complete migration tracks for nine individuals. During southbound migration, six of the nine Whimbrels stopped at two staging sites on the mid‐Atlantic seaboard of the United States for an average of 22 days, whereas three individuals made nonstop flights of ~8000 km from Churchill to South America. All individuals subsequently spent the entire non‐breeding season along the northern coasts of Brazil and Suriname. On their way north, all birds stopped at the same two staging sites used during southbound migration. Individuals staged at these sites for an average of 34 days, significantly longer than during southbound migration, and all departed within a 5‐day period to undertake nonstop flights ranging from 2600 to 3100 km to the breeding grounds. These extended spring stopovers suggest that female Whimbrels likely employ a mixed breeding strategy, drawing on both endogenous and exogenous reserves to produce their eggs. Our results also demonstrate that this breeding population exhibits a high degree of connectivity among breeding, staging, and wintering sites. As with other long‐distance migratory shorebirds, conservation efforts for this population of Whimbrels must therefore focus on a small, but widely spaced, suite of sites that support a large proportion of the population.

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Section: Discussionsupporting

confidence: 91%

“…They are long‐distance migratory shorebirds whose numbers have declined sharply at major stopover sites during the past two decades (Watts and Truitt ) and that are potentially under significant pressure from sport and subsistence hunting along portions of their migration route (Andres , Morrison et al. , Watts et al. ).…”

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Dichotomous strategies? The migration of Whimbrels breeding in the eastern Canadian sub-Arctic

et al. 2016

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“…Hicklin and Chardine (2012) interpreted the shorter metrics they reported around 2000 as support for the hypothesis that eastern, long-billed populations had recently undergone large and disproportionate population reductions, resulting in relatively lower usage of this migratory site than populations from central breeding areas. Surveys in North America (Morrison et al, 2001(Morrison et al, , 2006 and South America (Ottema & Spaans, 2008;Morrison et al, 2012) have reported strong declines, thought to represent primarily eastern populations (Brown et al, 2017; but see Andres et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Long‐term continental changes in wing length, but not bill length, of a long‐distance migratory shorebird

Lank

Harrington

et al. 2017

Ecology and Evolution

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We compiled a >50‐year record of morphometrics for semipalmated sandpipers (Calidris pusilla), a shorebird species with a Nearctic breeding distribution and intercontinental migration to South America. Our data included >57,000 individuals captured 1972–2015 at five breeding locations and three major stopover sites, plus 139 museum specimens collected in earlier decades. Wing length increased by ca. 1.5 mm (>1%) prior to 1980, followed by a decrease of 3.85 mm (nearly 4%) over the subsequent 35 years. This can account for previously reported changes in metrics at a migratory stopover site from 1985 to 2006. Wing length decreased at a rate of 1,098 darwins, or 0.176 haldanes, within the ranges of other field studies of phenotypic change. Bill length, in contrast, showed no consistent change over the full period of our study. Decreased body size as a universal response of animal populations to climate warming, and several other potential mechanisms, are unable to account for the increasing and decreasing wing length pattern observed. We propose that the post‐WWII near‐extirpation of falcon populations and their post‐1973 recovery driven by the widespread use and subsequent limitation on DDT in North America selected initially for greater flight efficiency and latterly for greater agility. This predation danger hypothesis accounts for many features of the morphometric data and deserves further investigation in this and other species.

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“…Most of the eastern population (84%) of Semipalmated Sandpipers spends the non‐breeding season in northeastern South America (Morrison et al. ), whereas the western and central populations appear to favor western South America as a non‐breeding site. Based on mean bill lengths, Gratto‐Trevor et al.…”

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Effects of migration distance on life history strategies of Western and Semipalmated sandpipers in Perú

2016

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Migration distances of shorebird species correlate with life history strategies. To assess age‐specific migratory preparation and adult wing‐molt strategies, we studied Western Sandpipers (Calidris mauri) and Semipalmated Sandpipers (C. pusilla) with different migration routes at the Paracas National Reserve in Perú, one of the most austral non‐breeding areas for these sandpipers, from 2012 to 2015. Western Sandpipers breed near the Bering Sea, ~11,000 km from Paracas. Semipalmated Sandpiper populations at Paracas are a mixture of short‐billed birds from western Arctic breeding sites, plus long‐billed birds from eastern sites, ~8000 km distant. Adults of both species arrive in October with primary feathers already partially renewed so wing molt starts at sites further north. Semipalmated Sandpipers with longer bills completed wing molt later than shorter billed birds. Adults of both species prepared for migration in February and March. No juvenile Western Sandpipers prepared for migration, confirming the “slow” over‐summering life history strategy of more southerly non‐breeding populations. Juvenile Semipalmated Sandpipers showed bimodality in strategies. Most showed no migratory preparation, but, during three non‐breeding periods, from 27% to 31% fattened, molted, and partially replaced outer primaries during the pre‐migratory period. Juveniles with longer culmens were heavier and tended to have more alternate plumage. Juveniles that were partially molting primaries had longer culmens and more alternate plumage. Juvenile Semipalmated Sandpipers from eastern‐breeding populations thus have a higher propensity for a fast life history strategy, and western birds a slow one, at this non‐breeding site in Peru. Western‐breeding Semipalmated Sandpiper populations thus resemble Western Sandpipers, suggesting a common, possibly distance‐related, effect on life history strategy.

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Dramatic Declines of Semipalmated Sandpipers on their Major Wintering Areas in the Guianas, Northern South America

Cited by 48 publications

References 19 publications

Dichotomous strategies? The migration of Whimbrels breeding in the eastern Canadian sub-Arctic

Dichotomous strategies? The migration of Whimbrels breeding in the eastern Canadian sub-Arctic

Long‐term continental changes in wing length, but not bill length, of a long‐distance migratory shorebird

Effects of migration distance on life history strategies of Western and Semipalmated sandpipers in Perú

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