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Ydenberg RC, Fernández G, Ortiz Lopez E, Lank DB. Avian wings can lengthen rather than shorten in response to increased migratory predation danger. Ecol Evol 2023; 13:e10325. [PMID: 37492461 PMCID: PMC10363853 DOI: 10.1002/ece3.10325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/20/2023] [Accepted: 06/29/2023] [Indexed: 07/27/2023] Open
Abstract
Increasing predation danger can select for safety-enhancing modifications to prey morphology. Here, we document the multi-decade wing lengthening of a Pacific flyway migrant, the western sandpiper (Calidris mauri), and contrast this with contemporaneous wing shortening of the closely related semipalmated sandpiper (C. pusilla) on the Atlantic flyway. We measured >12,000 southbound western sandpipers captured from 1978 to 2020 at a major stopover site in British Columbia. Wing length increased at 0.074 mm year-1 (SE = 0.017; p < .0003) for adults, and 0.087 mm year-1 (SE = 0.029; p < .007) for juveniles. These rates are of similarly large magnitude (4%-5% overall), but opposite in direction, to the rate we previously reported for semipalmated sandpiper adults (-0.103 mm year-1). In both species, the change is specific to wings rather than being part of a general body size change. We interpret both trends as responses to the ongoing strong increase of peregrine falcon (Falco peregrinus) populations since the mid-1970s, an important predator encountered by these species in contrasting ways during migration. Western sandpipers and peregrine migrations have temporal and spatial overlap. Longer wings enhance migratory speed and efficiency, enabling western sandpipers to decrease overlap by advancing to safer zones ahead of falcon passage. In contrast, semipalmated sandpipers primarily encounter peregrines as residents at migratory staging sites. Shorter wings improve acceleration and agility, helping migrants to escape attacks. Juvenile western sandpiper wing length also shows a component additive to the lengthening trend, shifting between years at 0.055 mm day-1 with the highly variable snowmelt date, with wings shorter following early springs. On the Pacific flyway, the timing of peregrine southward passage advances with snowmelt, increasing the relative exposure of juveniles to post-migratory resident peregrines. We interpret this annual wing length adjustment as an induced defense, made possible because snowmelt timing is a reliable cue to danger in the upcoming migration.
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Affiliation(s)
- Ronald C. Ydenberg
- Centre for Wildlife Ecology, Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
| | - Guillermo Fernández
- Unidad Académica Mazatlán, Instituto de Ciencias del Mary LimnologíaUniversidad Nacional Autónoma de MéxicoMazatlanMexico
| | | | - David B. Lank
- Centre for Wildlife Ecology, Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
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Youtz J, Miller KD, Bowers EK, Rogers SL, Bulluck LP, Johnson M, Peer BD, Percy KL, Johnson EI, Ames EM, Tonra CM, Boves TJ. Bergmann's rule is followed at multiple stages of postembryonic development in a long-distance migratory songbird. Ecol Evol 2020; 10:10672-10686. [PMID: 33072288 PMCID: PMC7548171 DOI: 10.1002/ece3.6721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/28/2020] [Accepted: 08/05/2020] [Indexed: 12/11/2022] Open
Abstract
Bergmann’s rule is a well‐established, ecogeographical principle that states that body size varies positively with latitude, reflecting the thermoregulatory benefits of larger bodies as temperatures decline. However, this principle does not seem to easily apply to migratory species that are able to avoid the extreme temperatures during winter at higher latitudes. Further, little is known about the ontogeny of this relationship across life stages or how it is influenced by ongoing global climate change. To address these knowledge gaps, we assessed the contemporary relationship between latitude and body size in a long‐distance migratory species, the prothonotary warbler (Protonotaria citrea) across life stages (egg to adult) on their breeding grounds. We also measured historic eggs (1865‐1961) to assess if the relationship between latitude and size during this life stage has changed over time. In accordance with Bergmann’s rule, we found a positive relationship between latitude and body mass during all post‐embryonic life stages, from early nestling stage through adulthood. We observed this same predicted pattern with historic eggs, but contemporary eggs exhibited the reverse (negative) relationship. We suggest that these results indicate a genetic component to this pattern and speculate that selection for larger body size in altricial nestlings as latitude increases may possibly drive the pattern in migratory species as even rare extreme cold weather events may cause mortality during early life stages. Furthermore, the opposite relationships observed in eggs, dependent on time period, may be related to the rapidly warming environments of higher latitudes that is associated with climate change. Although it is unclear what mechanism(s) would allow for this recent reversal in eggs (but still allow for its maintenance in later life stages). This evidence of a reversal suggests that anthropogenic climate change may be in the process of altering one of the longest‐standing principles in ecology.
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Affiliation(s)
- Joseph Youtz
- Department of Biological Sciences Arkansas State University State University Arkansas USA
| | - Kelly D Miller
- Department of Biological Sciences and Center for Biodiversity Research University of Memphis Memphis Tennessee USA
| | - Emerson K Bowers
- Department of Biological Sciences and Center for Biodiversity Research University of Memphis Memphis Tennessee USA
| | - Samantha L Rogers
- Center for Environmental Studies Virginia Commonwealth University Richmond Virginia USA.,Integrative Life Sciences Doctoral Program Virginia Commonwealth University Richmond Virginia USA
| | - Lesley P Bulluck
- Center for Environmental Studies Virginia Commonwealth University Richmond Virginia USA
| | - Matthew Johnson
- Audubon South Carolina National Audubon Society Harleyville South Carolina USA
| | - Brian D Peer
- Department of Biological Sciences Western Illinois University Moline Illinois USA
| | - Katie L Percy
- Audubon Louisiana National Audubon Society Baton Rouge Louisiana USA
| | - Erik I Johnson
- Audubon Louisiana National Audubon Society Baton Rouge Louisiana USA
| | - Elizabeth M Ames
- School of Environment and Natural Resources The Ohio State University Columbus Ohio USA
| | - Christopher M Tonra
- School of Environment and Natural Resources The Ohio State University Columbus Ohio USA
| | - Than J Boves
- Department of Biological Sciences Arkansas State University State University Arkansas USA
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Weeks BC, Willard DE, Zimova M, Ellis AA, Witynski ML, Hennen M, Winger BM. Shared morphological consequences of global warming in North American migratory birds. Ecol Lett 2019; 23:316-325. [PMID: 31800170 DOI: 10.1111/ele.13434] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 10/30/2019] [Indexed: 12/23/2022]
Abstract
Increasing temperatures associated with climate change are predicted to cause reductions in body size, a key determinant of animal physiology and ecology. Using a four-decade specimen series of 70 716 individuals of 52 North American migratory bird species, we demonstrate that increasing annual summer temperature over the 40-year period predicts consistent reductions in body size across these diverse taxa. Concurrently, wing length - an index of body shape that impacts numerous aspects of avian ecology and behaviour - has consistently increased across species. Our findings suggest that warming-induced body size reduction is a general response to climate change, and reveal a similarly consistent and unexpected shift in body shape. We hypothesise that increasing wing length represents a compensatory adaptation to maintain migration as reductions in body size have increased the metabolic cost of flight. An improved understanding of warming-induced morphological changes is important for predicting biotic responses to global change.
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Affiliation(s)
- Brian C Weeks
- School for Environment and Sustainability, University of Michigan, Dana Natural Resources Building, 440 Church St, Ann Arbor, MI, 49109, USA.,Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Biological Sciences Building, 1105 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - David E Willard
- Gantz Family Collection Center, The Field Museum, 1400 S. Lake Shore Dr, Chicago, IL, 60605, USA
| | - Marketa Zimova
- School for Environment and Sustainability, University of Michigan, Dana Natural Resources Building, 440 Church St, Ann Arbor, MI, 49109, USA
| | - Aspen A Ellis
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Biological Sciences Building, 1105 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Max L Witynski
- Gantz Family Collection Center, The Field Museum, 1400 S. Lake Shore Dr, Chicago, IL, 60605, USA
| | - Mary Hennen
- Gantz Family Collection Center, The Field Museum, 1400 S. Lake Shore Dr, Chicago, IL, 60605, USA
| | - Benjamin M Winger
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Biological Sciences Building, 1105 N. University Avenue, Ann Arbor, MI, 48109, USA
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