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1. Factors affecting the nesting success of Swainson's Thrush ( Catharus ustulatus ) along an elevational gradient

   https://doi.org/10.1002/ece3.10738  

   Deckel, Sarah_C ; DeLuca, William_V ; Gerson, Alexander_R ; King, David_I ( January 2024 , Ecology and Evolution)

   Montane birds experience a range of challenges that may limit their breeding success, including nest predation and severe climactic conditions. The continuing effects of climate change are causing shifts in biotic and abiotic factors that may compound these threats to montane bird species. In northeastern montane forests, many bird species are shifting downslope, potentially as the result of increased precipitation and temperature at higher elevations. Although lower elevations might be more favorable in terms of climactic conditions, nest predation is higher at lower elevations. Thus, montane birds might be faced with the opposing pressures of adverse climactic conditions at higher elevations and increased predation at lower elevations. We monitored nests of Swainson's Thrush (Catharus ustulatus) along an elevation gradient in the White Mountain National Forest in New Hampshire in 2016, 2018, 2019, and 2021 to examine the effect of biotic and abiotic factors on daily nest survival rate (DSR). Linear time explained the most variation of DSR in AICc model comparison, indicating that DSR decreases across the breeding season. Rain intensity (mm/h) had a weak negative effect on DSR, indicating that heavier rain per hour decreases Swainson's Thrush DSR. Moreover, we found some support for a negative interaction effect of elevation in conjunction with minimum daily temperature: DSR of Swainson's Thrush nests at low elevations (281 m) increased with increasing minimum daily temperatures and decreased at high elevations with increasing minimum daily temperatures. Our results suggest nesting survival of montane breeding birds may be at risk as heavier precipitation events become more frequent and intense due to the changing climate and raises the possibility that other passerine species could be at risk in this system.

    

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2. Biotic and abiotic factors affecting Atlantic ghost crab (Ocypode quadrata) spatiotemporal activity at an important shorebird nesting site in Virginia

   https://doi.org/10.1371/journal.pone.0307821  

   Call, Mikayla N ; Pongnon, Rasheed S ; Wails, Christy N ; Karpanty, Sarah M ; Lapenta, Kristy C ; Wilke, Alexandra L ; Boettcher, Ruth ; Alvino, Camille R ; Fraser, James D ( August 2024 , PLOS ONE)

   Romanach, Stephanie S (Ed.)

   Atlantic ghost crabs (Ocypode quadrata) are predators of beach-nesting shorebird nests and chicks on the United States’ Atlantic and Gulf coasts. Ghost crabs may also disturb birds, altering foraging, habitat use, or nest and brood attendance patterns. Shorebird conservation strategies often involve predator and disturbance management to improve reproductive success, but efforts rarely target ghost crabs. Despite the threat to shorebird reproductive success, ghost crabs are a poorly understood part of the beach ecosystem and additional knowledge about ghost crab habitat selection is needed to inform shorebird conservation. We monitored ghost crab activity, defined as burrow abundance, throughout the shorebird breeding season on Metompkin Island, Virginia, an important breeding site for piping plovers (Charadrius melodus) and American oystercatchers (Haematopus palliatus). We counted burrows at shorebird nests and random locations throughout the breeding season and investigated whether ghost crab activity was greater at nest sites relative to random locations without shorebird nests. While we observed burrows at all nest sites (n= 63 nests), we found that burrow counts were lower at piping plover nests with shell cover, relative to random locations with no shell cover. Ghost crabs may avoid piping plover nest sites due to anti-predator behaviors from incubating adults or differences in microhabitat characteristics selected by piping plovers. We also investigated the effects of habitat type, date, and air temperature on the abundance of ghost crab burrows. We found that while crab burrows were present across the barrier island landscape, there were more burrows in sandy, undisturbed habitats behind the dunes, relative to wave-disturbed beach. Additionally, ghost crab activity increased later in the shorebird breeding season. Understanding when and where ghost crabs are most likely to be active in the landscape can aid decision-making to benefit imperiled shorebird populations.

    

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3. Seasonal associations with novel climates for North American migratory bird populations

   https://doi.org/10.1111/ele.12951  

   La Sorte, Frank A. ; Fink, Daniel ; Johnston, Alison ; Norris, ed., Ryan ( April 2018 , Ecology Letters)

   Determining the implications of global climate change for highly mobile taxa such as migratory birds requires a perspective that is spatiotemporally comprehensive and ecologically relevant. Here, we document how passerine bird species that migrate within the Western Hemisphere (n = 77) are associated with projected novel climates across the full annual cycle. Following expectations, highly novel climates occurred on tropical non‐breeding grounds and the least novel climates occurred on temperate breeding grounds. Contrary to expectations, highly novel climates also occurred within temperate regions during the transition from breeding to autumn migration. This outcome was caused by lower inter‐annual climatic variability occurring in combination with stronger warming projections. Thus, migrants are projected to encounter novel climates across the majority of their annual cycle, with a pronounced peak occurring when juveniles are leaving the nest and preparing to embark on their first migratory journey, which may adversely affect their chances of survival.

    

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4. Does vegetation change over 28 years affect habitat use and reproductive success?

   https://doi.org/10.1093/auk/ukz061  

   Fierro-Calderón, Karolina ; Martin, Thomas E. ( November 2019 , The Auk)

   Individuals should prefer and use habitats that confer high fitness, but habitat use is not always adaptive. Vegetation in natural landscapes changes gradually and the ability of species to adaptively adjust their habitat use to long-term changes is largely unstudied. We studied nest patch and territory use over 28 yr in Orange-crowned Warblers (Oreothlypis celata) in a system that has undergone natural long-term changes in vegetation. Abundance of maple (Acer grandidentatum), its preferred nesting habitat, gradually declined from 1987 to 2015. We examined whether habitat use and its fitness consequences changed as the availability of preferred habitat decreased. We used resource selection function models to determine changes over time in the probability of using a nest patch given available patches, and the probability of using a territory given available territories. We estimated nest survival to evaluate changes over time in the fitness consequences of nest patch use. We also compared habitat use (nest patch and territory) and fitness (nest survival) between areas with naturally reduced abundance of maple and experimentally increased abundance of maple (fenced areas). Nest patch use depended on maple abundance and did not change drastically across 28 yr, even though the availability of preferred maple patches decreased over time. In contrast, nest survival tended to decrease over time. We did not see differences in nest patch use and nest survival between unfenced and fenced areas, unlike territory use, which increased with the abundance of maple in fenced areas and decreased in unfenced areas. Our study depicts one example of relatively unchanged habitat use in the face of decreased availability of preferred vegetation across years, with a resulting decrease in reproductive success. Investigating changes in habitat use and fitness consequences for animals exposed to long-term habitat change is necessary to understand adaptive behavioral responses.

    

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5. Prey availability and foraging activity by tundra‐nesting sea ducks: Strong preference for specific wetland types

   https://doi.org/10.1002/ece3.10375  

   Miller, Micah W. C. ; Lovvorn, James R. ; Graff, Nathan R. ; Stellrecht, Neesha C. ; Plesh, Steven P. ( September 2023 , Ecology and Evolution)

   Wetlands in Arctic tundra support abundant breeding waterbirds. Wetland types differing in area, depth, vegetation, and invertebrate biomass density may vary in importance to birds, and in vulnerability to climate change. We studied availability and use of different wetland types by prelaying females of four species of sea ducks (Mergini) breeding on the Arctic Coastal Plain of Alaska, USA: long‐tailed ducks (Clangula hyemalis) and Steller's (Polysticta stelleri), spectacled (Somateria fischeri), and king eiders (Somateria spectabilis). All four species preferred shallow vegetated wetlands versus deeper lakes. The ducks spent almost all their active time feeding, but their occurrence in different wetland types was not affected by the relative biomass density of known prey or of all invertebrates that we sampled combined. Sea ducks strongly preferred wetlands dominated by emergent and submersedArctophila fulvaover those dominated by the sedgeCarex aquatilis, despite the much greater number, total area, and invertebrate biomass density ofCarexwetlands. The hens depend heavily on local invertebrate prey for protein to produce eggs; thus, their preference forArctophilawetlands likely reflects greater accessibility of prey in the near‐surface canopy and detritus ofArctophila. Such shallow wetlands decreased substantially in number (−17%) and area (−30%) over 62 years before 2013 and appear highly susceptible to further declines with climate warming. Impacts on sea ducks of climate‐driven changes in availability of important wetland types will depend on their adaptability in exploiting alternative wetlands.

    

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