Foraging ecology of sanderlings Calidris alba wintering in estuarine and non-estuarine intertidal areas

Lourenço, Pedro M.; Alves, José A.; Catry, Teresa; Granadeiro, José Pedro

doi:10.1016/j.seares.2015.06.013

Cited by 12 publications

(11 citation statements)

References 43 publications

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“…These beaches only persist there due to intense artificial sediment nourishment ( Ferreira & Matias, 2013 ) which can result in severe ecological impacts and loss of biodiversity ( Schlacher et al, 2007 ). In fact, data collected in parallel to this study indicate both food availability and sanderling intake rates are currently lower in Caparica than in the sites within the estuary ( Lourenço et al, 2015 ). Despite this, sanderlings continue to use this site and the few birds ringed in the estuary that were sighted in Caparica continued to use the site throughout the winter.…”

Section: Discussionmentioning

confidence: 70%

“…The maximum distance between our study sites was 29.8 km, which is a very considerable distance and larger than in many similar studies (e.g., Evans, Breary & Goodyer, 1980 ; Groen, 1993 ; Burton & Evans, 1997 ; Leyrer et al, 2006 ), but we still may be failing to detect movements to areas located further away. There is also the possibility that within this 30 km radius birds could use other sites within and in the vicinity of the estuary that were not monitored, although the relatively rare occurrence of sandy substrates in the Tejo estuary and the known preference sanderlings show for these substrates suggest this is unlikely ( Lourenço et al, 2015 ). Also, since ringing only took place in the three sites within the estuary, and not on the furthest sites located outside the estuary, while the latter were probably visited less often, there might be a bias against detecting movements over larger distances.…”

Section: Discussionmentioning

confidence: 99%

“…In Alcochete birds also roost on a saltpan located near the beach, which was also routinely monitored during the study. All sites harbour sanderling flocks throughout the winter with average counts of 75–126 individuals per site (more details regarding the study area in Lourenço et al, 2015 ).…”

Section: Methodsmentioning

confidence: 99%

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Influence of age and sex on winter site fidelity of sanderlingsCalidris alba

Lourenço

Alves

Reneerkens

et al. 2016

PeerJ

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Many migratory bird species show high levels of site fidelity to their wintering sites, which confers advantages due to prior knowledge, but may also limit the ability of the individual to move away from degrading sites or to detect alternative foraging opportunities. Winter site fidelity often varies among age groups, but sexual differences have seldom been recorded in birds. We studied a population of individually colour-marked sanderlings wintering in and around the Tejo estuary, a large estuarine wetland on the western coast of Portugal. For 160 individuals, sighted a total of 1,249 times between November 2009 and March 2013, we calculated the probability that they moved among five distinct wintering sites and how this probability is affected by distance between them. To compare site fidelity among age classes and sexes, as well as within the same winter and over multiple winters, we used a Site Fidelity Index (SFI). Birds were sexed using a discriminant function based on biometrics of a large set of molecularly sexed sanderlings (n = 990). The vast majority of birds were observed at one site only, and the probability of the few detected movements between sites was negatively correlated with the distance among each pair of sites. Hardly any movements were recorded over more than 15 km, suggesting small home ranges. SFI values indicated that juveniles were less site-faithful than adults which may reflect the accumulated knowledge and/or dominance of older animals. Among adults, females were significantly less site faithful than males. A sexual difference in winter site fidelity is unusual in shorebirds. SFI values show site-faithfulness is lower when multiple winters were considered, and most birds seem to chose a wintering site early in the season and use that site throughout the winter. Sanderlings show a very limited tendency to explore alternative wintering options, which might have implications for their survival when facing habitat change or loss (e.g., like severe beach erosion as can be the case at one of the study sites).

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Section: Discussionmentioning

confidence: 70%

Section: Discussionmentioning

confidence: 99%

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Influence of age and sex on winter site fidelity of sanderlingsCalidris alba

Lourenço

Alves

Reneerkens

et al. 2016

PeerJ

Self Cite

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“…In these estuaries, migratory shorebirds are important predators and are pivotal in regulating macroinvertebrate abundances (Schneider andHarrington 1981, Steinmetz et al 2003). Mudflat ecosystems provide shorebirds with high quality, often preferred, foraging habitat (Burger et al 1977, Lourenc ßo et al 2015. Furthermore, the estuaries of the southeastern United States serve as important stopover and over-wintering sites for many shorebird species that migrate between the Arctic and the tropics using the Atlantic Flyway.…”

Section: Research System and Questionsmentioning

confidence: 99%

“…, Lourenço et al. ). Furthermore, the estuaries of the southeastern United States serve as important stopover and over‐wintering sites for many shorebird species that migrate between the Arctic and the tropics using the Atlantic Flyway.…”

Section: Introductionmentioning

confidence: 99%

Mixed effects of an introduced ecosystem engineer on the foraging behavior and habitat selection of predators

Haram

Kinney

Sotka

et al. 2018

Ecology

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Invasive ecosystem engineers both positively and negatively affect their recipient ecosystems by generating novel habitats. Many studies have focused on alterations to ecosystem properties and to native species diversity and abundance caused by invasive engineers. However, relatively few studies have documented the extent to which behaviors of native species are affected. The red seaweed Gracilaria vermiculophylla (Rhodophyta) invaded estuaries of the southeastern United States within the last few decades and now provides abundant aboveground vegetative cover on intertidal mudflats that were historically devoid of seaweeds. We hypothesized that G. vermiculophylla would affect the foraging behavior of native shorebirds positively for birds that target seaweed‐associated invertebrates or negatively for birds that target prey on or within the sediment now covered with seaweed. Visual surveys of mudflats >1 ha in size revealed that more shorebirds occurred on mudflats with G. vermiculophylla relative to mudflats without G. vermiculophylla. This increased density was consistent across 7 of 8 species, with the one exception being the semipalmated plover Charadrius semipalmatus. A regression‐based analysis indicated that while algal presence predicted shorebird density, densities of some bird species depended on sediment composition and infaunal invertebrate densities. At smaller spatial scales (200 m2 and <1 m2), experimental removals and additions of G. vermiculophylla and focal observations showed strong variation in behavioral response to G. vermiculophylla among bird species. Birds preferentially foraged in bare mud (e.g., C. semipalmatus), in G. vermiculophylla (e.g., Arenaria interpres), or displayed no preference for either habitat (e.g., Tringa semipalmata). Thus, while the presence of the invasive ecosystem engineer on a mudflat appeared to attract greater numbers of these predators, shorebird species differed in their behavioral responses at the smaller spatial scales that affect their foraging. Our research illuminates the need to account for species identity, individual behavior, and scale when predicting the impacts of invasive species on native communities.

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Variety in responses of wintering oystercatchersHaematopus ostralegusto near‐collapse of their prey in the Exe Estuary,UK

Morten

Burrell

Frayling

et al. 2022

Ecology and Evolution

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Globally, habitat loss or degradation is a major threat to many species, and those with specific habitat requirements are particularly vulnerable. Many species of wading birds (Charadrii) are dependent upon intertidal sites to feed, but, as a result of anthropogenic pressures, the prey landscape has changed at many estuaries. Behavioral adaptations may be able to buffer these changes. In this study over multiple seasons, we aimed to investigate the foraging behaviors of wintering Eurasian oystercatchers in the Exe Estuary where mussel beds, the preferred prey at this site, have almost disappeared in the last decade. From 2018 to 2021, GPS tracking devices were deployed on 24 oystercatchers, and the foraging locations of adults, sub-adults, and juveniles were determined. Of the 12 birds tracked over multiple winter periods, 10 used the same foraging home ranges but a juvenile and sub-adult changed locations interannually. The dominant prey species at key foraging sites were assessed, and we found that younger birds were more likely to visit sites with lower quality prey, likely due to being at a competitive disadvantage, and also to explore sites further away. Individuals were generally consistent in the areas of the estuary used in early and late winter, and over 90% of locations were recorded in the protected area boundary, which covers the sand and mudflats of the Exe. These findings suggest high specificity of the current protected area for oystercatchers in the Exe Estuary, although, if the prey landscape continues to decline, younger individuals may provide the potential for adaptation by finding and foraging at additional sites. Continued monitoring of individual behavior within populations that are facing dramatic changes to their prey is essential to understand how they may adapt and to develop suitable management plans to conserve threatened species.

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Foraging ecology of sanderlings Calidris alba wintering in estuarine and non-estuarine intertidal areas

Cited by 12 publications

References 43 publications

Influence of age and sex on winter site fidelity of sanderlingsCalidris alba

Influence of age and sex on winter site fidelity of sanderlingsCalidris alba

Mixed effects of an introduced ecosystem engineer on the foraging behavior and habitat selection of predators

Variety in responses of wintering oystercatchersHaematopus ostralegusto near‐collapse of their prey in the Exe Estuary,UK

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