Annual patterns of abundance of Nearctic shorebirds and their prey at two estuarine sites in Ceará, NE Brazil, 2008–2009

Fedrizzi, Carmem Elisa; Carlos, Caio J.; Campos, Alberto Alves

doi:10.18194/ws.00036

Cited by 9 publications

(6 citation statements)

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“…Semipalmated sandpipers are generalist foragers (Kober & Bairlein, 2006) that may be able to adapt to using altered habitats as long as there is a suitable food source available. Conversely, other species like Red Knot ( Calidris canutus rufa ), which are common at the Banco dos Cajuais and are globally threatened (Fedrizzi et al, 2016), are potentially less flexible. These birds have a more specialized diet (Kober & Bairlein, 2006), preferring to forage on bivalves (Martínez‐Curci et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…The Banco dos Cajuais, located in the state of Cear a in northeastern Brazil, is a Western Hemisphere Shorebird Reserve Network site of regional importance (WHSRN Sites, n.d.) designated in 2017. This WHSRN site supports a diverse assemblage of resident and Nearctic migratory shorebirds, including semipalmated sandpipers, and is characterized by extensive tidal flats, beachfront, dunes, coastal scrub, mangrove forest and a mosaic of salt flats mixed with salt evaporation ponds and shrimp farms (Albano et al, 2007;Fedrizzi et al, 2016;Meireles & Santos, 2011;Valente et al, 2011). Although the area is relatively small, the diversity of habitats at the Banco dos Cajuais is representative of other coastal areas in northeastern South America (Campos et al, 2003).…”

Section: Introductionmentioning

confidence: 94%

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Movement and habitat use of non‐breeding Semipalmated Sandpiper (Calidris pusilla) at the Banco dos Cajuais in Northeast Brazil

Linhart

Hamilton

Paquet

et al. 2022

Conservat Sci and Prac

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Semipalmated sandpipers are Arctic breeding shorebirds that migrate to South America during the non‐breeding season. Little work has been done to understand the daily movements, foraging habits and metabolic state of this species on stationary nonbreeding grounds. Our work was conducted at the Banco dos Cajuais Western Hemisphere Shorebird Reserve Network (WHSRN) site in Northeast Brazil. We captured semipalmated sandpipers in February and March 2019 and 2020 and attached nanotags to monitor their daily movements. Blood samples were taken to measure plasma triglycerides (an index of fattening rate). We also conducted behavioral observations on foraging birds. Using tracking data we determined that most semipalmated sandpipers appeared to use sunrise/sunset as an indicator for movement between salina and tidal flat habitats, and a smaller portion used tidal height. We found birds spent similar amounts of time foraging on tidal flats and in salinas, though different foraging modes were used. Plasma triglyceride measures suggest semipalmated sandpipers had not started preparing to migrate when sampled. We successfully tracked semipalmated sandpipers to North America during northward migration in 2020, detecting eight within the United States. Tracking results suggest many stopped elsewhere in South America to fuel for migration, though some may have fueled at the Banco dos Cajuais. By demonstrating substantial use of both natural and altered habitats in the region by migrant semipalmated sandpipers, these data highlight the need for broader conservation measures throughout coastal regions of South America.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Movement and habitat use of non‐breeding Semipalmated Sandpiper (Calidris pusilla) at the Banco dos Cajuais in Northeast Brazil

Linhart

Hamilton

Paquet

et al. 2022

Conservat Sci and Prac

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“…Shorebirds usually evacuate crushed shell material from the gut as feces . The regurgitation of pellets, which occurs in Tringids but has not often been reported in Calidrid sandpipers Fedrizzi, Carlos, & Campos, 2016;Worrall, 1984), coincided with the strongly increased break forces required for ingested prey in 2016 and 2017.…”

Section: Discussionmentioning

confidence: 80%

“…Shorebirds usually evacuate crushed shell material from the gut as feces (Battley & Piersma, ). The regurgitation of pellets, which occurs in Tringids but has not often been reported in Calidrid sandpipers (Dekinga & Piersma, ; Fedrizzi, Carlos, & Campos, ; Worrall, ), coincided with the strongly increased break forces required for ingested prey in 2016 and 2017. It appears that Great Knots were unable to crush the extremely hard calcified columella of U. thomasi .…”

Section: Discussionmentioning

confidence: 84%

Morphological and digestive adjustments buffer performance: How staging shorebirds cope with severe food declines

Zhang

Choi

et al. 2019

Ecology and Evolution

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Organisms cope with environmental stressors by behavioral, morphological, and physiological adjustments. Documentation of such adjustments in the wild provides information on the response space in nature and the extent to which behavioral and bodily adjustments lead to appropriate performance effects. Here we studied the morphological and digestive adjustments in a staging population of migrating Great Knots Calidris tenuirostris in response to stark declines in food abundance and quality at the Yalu Jiang estuarine wetland (northern Yellow Sea, China). At Yalu Jiang, from 2011 to 2017 the densities of intertidal mollusks, the food of Great Knots, declined 15‐fold. The staple prey of Great Knots shifted from the relatively soft‐shelled bivalve Potamocorbula laevis in 2011–2012 to harder‐shelled mollusks such as the gastropod Umbonium thomasi in 2016–2017. The crushing of the mollusks in the gizzard would require a threefold to 11‐fold increase in break force. This was partially resolved by a 15% increase in gizzard mass which would yield a 32% increase in shell processing capacity. The consumption of harder‐shelled mollusks was also accompanied by reliance on regurgitates to excrete unbreakable parts of prey, rather than the usual intestinal voidance of shell fragments as feces. Despite the changes in digestive morphology and strategy, there was still an 85% reduction in intake rate in 2016–2017 compared with 2011–2012. With these morphological and digestive adjustments, the Great Knots remaining faithful to the staging site to a certain extent buffered the disadvantageous effects of dramatic food declines. However, compensation was not complete. Locally, birds will have had to extend foraging time and use a greater daily foraging range. This study offers a perspective on how individual animals may mitigate the effects of environmental change by morphological and digestive strategies and the limits to the response space of long‐distance migrating shorebirds in the wild.

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“…The survival gains for semipalmated sandpipers at Paracas (adult s = 0.215, yearling s = 0.140) are higher than those gained by western sandpipers, and, notably, both lie within ~10% of their respective thresholds. The partial over‐summering of semipalmated sandpipers (yearlings 29%, adults 19%) would be explained if intraspecific variation in health, parasite load, plumage quality or other condition factors (McNeil et al 1994, Fedrizzi et al 2004, Martínez‐Curci et al 2020; but see Conklin et al 2017) were large enough that corresponding variation in the expected survival gain spans the threshold (Fig. 2).…”

Section: Over‐summeringmentioning

confidence: 99%

Danger, risk and anti‐predator behavior in the life history of long‐distance migratory sandpipers

Ydenberg

Tavera

Lank

2022

Journal of Avian Biology

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Two recent and independent studies both estimate substantially lower survival rates of semipalmated Calidris pusilla than of western C. mauri sandpipers, consistent with the pronounced multi-decade population decline of the former. Migratory danger has climbed steadily for both these long-distance migrants since the mid-1970s as the number of peregrine falcons Falco peregrinus increased. These predators are present on the Pacific flyway as co-migrants and are a natural (though now more abundant) feature of western sandpiper southbound migrations. Adjustments to migratory speed, timing and routing enable them to mitigate the danger. On the Atlantic flyway peregrines were introduced and breeding populations established in the 1980s at key staging areas, creating a novel hazard for southbound semipalmated sandpipers. Adjustments to migratory timing and speed do not aid in eluding such resident predators, and alternative routes are not available. Semipalmated sandpipers as a consequence have few effective defenses to counter this heightened danger, and we hypothesize that migratory mortality has increased, making over-summering (i.e. skipping a breeding season) more advantageous. The risk effects (i.e. the consequent reduction in population growth rate) so generated are substantial, and may be able to account for a large portion of the population decline.

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Annual patterns of abundance of Nearctic shorebirds and their prey at two estuarine sites in Ceará, NE Brazil, 2008–2009

Cited by 9 publications

References 0 publications

Movement and habitat use of non‐breeding Semipalmated Sandpiper (Calidris pusilla) at the Banco dos Cajuais in Northeast Brazil

Movement and habitat use of non‐breeding Semipalmated Sandpiper (Calidris pusilla) at the Banco dos Cajuais in Northeast Brazil

Morphological and digestive adjustments buffer performance: How staging shorebirds cope with severe food declines

Danger, risk and anti‐predator behavior in the life history of long‐distance migratory sandpipers

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