The Morphometrics of Migrant Semipalmated Sandpipers in the Bay of Fundy: Evidence for Declines in the Eastern Breeding Population

Hicklin, Peter W.; Chardine, John W.

doi:10.1675/063.035.0108

Cited by 18 publications

(32 citation statements)

References 21 publications

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“…For the Bay of Fundy, modeling of all years’ bill length means showed support for a quadratic, but not a linear fit (mean bill length = 8510.04 − 8.49* year + 0.002*year 2 , F = 13.28 [1,15] , p = .002), similar to the pattern found for wings (Figure d). Thus after the decline in the 1990s found by Hicklin and Chardine (), in recent years, mean bill lengths returned to historical values (Figure d, Bliss ).…”

Section: Resultsmentioning

confidence: 65%

“…We compared annual rates of change in metrics among regions by testing for interactions (region*year) with analysis of covariance, although inference was limited due to little overlap of time periods with data among regions. Because differential migration can produce seasonal biases in sex ratio (Hicklin & Chardine, ), we excluded from trend analyses site‐years when birds were sampled for limited time periods (Bay of Fundy: 1984, 2006 for wing lengths only; Manomet: 1986, 1991, 1995). An alternative approach using least‐squared annual means corrected for date of capture to adjust for sex ratio effects at migration sites, assuming common seasonal slopes over years (Hicklin & Chardine, ), produced results similar to those presented here.…”

Section: Methodsmentioning

confidence: 99%

“…The remaining central Arctic breeders, and all eastern Arctic birds, migrate south via the Atlantic coast, particularly the Bay of Fundy. Hicklin and Chardine () 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., , ) and South America (Ottema & Spaans, ; Morrison et al., ) have reported strong declines, thought to represent primarily eastern populations (Brown et al., ; but see Andres et al., ).…”

Section: Introductionmentioning

confidence: 94%

“…Interpreting changes in morphometrics of birds captured at migratory stopover sites is complicated because changes in the metrics can occur in several ways related to sample biases, even in the absence of any real phenotypic changes. If body size differs among breeding areas, changing representation bias from different areas of origin would alter metrics (Hicklin & Chardine, ). If the sexes differ in size or passage time, a change in sex ratio or the timing of sampling relative to this progression could also alter population metrics.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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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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“…Their concentration during critical refueling periods at high‐quality, but at‐risk, sites makes migratory shorebirds particularly vulnerable to environmental change and degradation of stopover habitats, both of which have contributed to widespread population declines among many shorebird taxa (Andres et al. , Hicklin and Chardine , Ross et al. ).…”

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confidence: 99%

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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Avian wings can lengthen rather than shorten in response to increased migratory predation danger

Ydenberg

Fernández

Ortiz Lopez

et al. 2023

Ecology and Evolution

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The Morphometrics of Migrant Semipalmated Sandpipers in the Bay of Fundy: Evidence for Declines in the Eastern Breeding Population

Cited by 18 publications

References 21 publications

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

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

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

Avian wings can lengthen rather than shorten in response to increased migratory predation danger

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