Drivers of variation in migration behavior for a linked population of long-distance migratory passerine

The Auk ◽  
2019 ◽  
Vol 136 (4) ◽  
Author(s):  
Ruth E Bennett ◽  
Amanda D Rodewald ◽  
Kenneth V Rosenberg ◽  
Richard Chandler ◽  
Liliana Chavarria-Duriaux ◽  
...  

Abstract Despite advances in tracking technologies, migration strategies remain poorly studied for many small-bodied passerines. Understanding variation within a migration strategy is important as variation impacts a population’s resilience to environmental change. Timing, pathway, and stopovers vary based on intrinsic and extrinsic factors that impact individual migration decisions and capacity. Here, we studied drivers of variation in migration across a linked population of Golden-winged Warbler (Vermivora chrysoptera) using data from 37 light-level geolocators. We tested if behaviors vary in response to extrinsic factors: season, year, and proximity to a large geographic barrier—the Gulf of Mexico—and intrinsic factors: age and wing chord. Spring migration was nearly twice as fast as fall migration, with tightly correlated arrival and departure dates that were consistent among years, in contrast to no correlation or consistency in fall. This aligns with predictions for selection to minimize time spent migrating in spring and a relaxation of that pressure in fall. Twenty-nine birds staged for multiple days (mean: 7.5, SE: 0.6) in stopover habitats before crossing the Gulf of Mexico in spring, but 6 individuals overwintering closer to the Gulf coast forewent the stopover and completed migration 8 days faster. These findings suggest birds capable of crossing the Gulf without a stopover may experience a selective advantage by minimizing total migration time. After crossing the Gulf, individuals reduced travel speed and stopover duration, indicating constraints on movement differ before and after the barrier. Wing chord, but not age, positively predicted the total distance and duration of migration, and neither varied with timing, suggesting migration distance impacts morphology, but strategies do not vary with age. Ultimately, we find undescribed stopover locations south of the Gulf are important for most of the population, while high variation in migration behaviors suggest potential resilience to changing environmental conditions. Causantes de variación en el comportamiento migratorio para una población vinculada de un paseriforme migratorio de larga distancia

2011 ◽  
Vol 7 (6) ◽  
pp. 833-835 ◽  
Author(s):  
Raymond H. G. Klaassen ◽  
Thomas Alerstam ◽  
Peter Carlsson ◽  
James W. Fox ◽  
Åke Lindström

Migratory land birds perform extreme endurance flights when crossing ecological barriers, such as deserts, oceans and ice-caps. When travelling over benign areas, birds are expected to migrate by shorter flight steps, since carrying the heavy fuel loads needed for long non-stop flights comes at considerable cost. Here, we show that great snipes Gallinago media made long and fast non-stop flights (4300–6800 km in 48–96 h), not only over deserts and seas but also over wide areas of suitable habitats, which represents a previously unknown migration strategy among land birds. Furthermore, the great snipes achieved very high ground speeds (15–27 m s −1 ), which was not an effect of strong tailwind support, and we know of no other animal that travels this rapidly over such a long distance. Our results demonstrate that some migratory birds are prepared to accept extreme costs of strenuous exercise and large fuel loads, even when stopover sites are available along the route and there is little tailwind assistance. A strategy of storing a lot of energy before departure, even if migration is over benign habitats, may be advantageous owing to differential conditions of fuel deposition, predation or infection risk along the migration route.


2021 ◽  
Vol 9 ◽  
Author(s):  
Eliezer Gurarie ◽  
Sriya Potluri ◽  
George Christopher Cosner ◽  
Robert Stephen Cantrell ◽  
William F. Fagan

Seasonal migrations are a widespread and broadly successful strategy for animals to exploit periodic and localized resources over large spatial scales. It remains an open and largely case-specific question whether long-distance migrations are resilient to environmental disruptions. High levels of mobility suggest an ability to shift ranges that can confer resilience. On the other hand, a conservative, hard-wired commitment to a risky behavior can be costly if conditions change. Mechanisms that contribute to migration include identification and responsiveness to resources, sociality, and cognitive processes such as spatial memory and learning. Our goal was to explore the extent to which these factors interact not only to maintain a migratory behavior but also to provide resilience against environmental changes. We develop a diffusion-advection model of animal movement in which an endogenous migratory behavior is modified by recent experiences via a memory process, and animals have a social swarming-like behavior over a range of spatial scales. We found that this relatively simple framework was able to adapt to a stable, seasonal resource dynamic under a broad range of parameter values. Furthermore, the model was able to acquire an adaptive migration behavior with time. However, the resilience of the process depended on all the parameters under consideration, with many complex trade-offs. For example, the spatial scale of sociality needed to be large enough to capture changes in the resource, but not so large that the acquired collective information was overly diluted. A long-term reference memory was important for hedging against a highly stochastic process, but a higher weighting of more recent memory was needed for adapting to directional changes in resource phenology. Our model provides a general and versatile framework for exploring the interaction of memory, movement, social and resource dynamics, even as environmental conditions globally are undergoing rapid change.


PLoS Genetics ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. e1009877
Author(s):  
Alexander T. Lin-Moore ◽  
Motunrayo J. Oyeyemi ◽  
Marc Hammarlund

Injured axons must regenerate to restore nervous system function, and regeneration is regulated in part by external factors from non-neuronal tissues. Many of these extrinsic factors act in the immediate cellular environment of the axon to promote or restrict regeneration, but the existence of long-distance signals regulating axon regeneration has not been clear. Here we show that the Rab GTPase rab-27 inhibits regeneration of GABAergic motor neurons in C. elegans through activity in the intestine. Re-expression of RAB-27, but not the closely related RAB-3, in the intestine of rab-27 mutant animals is sufficient to rescue normal regeneration. Several additional components of an intestinal neuropeptide secretion pathway also inhibit axon regeneration, including NPDC1/cab-1, SNAP25/aex-4, KPC3/aex-5, and the neuropeptide NLP-40, and re-expression of these genes in the intestine of mutant animals is sufficient to restore normal regeneration success. Additionally, NPDC1/cab-1 and SNAP25/aex-4 genetically interact with rab-27 in the context of axon regeneration inhibition. Together these data indicate that RAB-27-dependent neuropeptide secretion from the intestine inhibits axon regeneration, and point to distal tissues as potent extrinsic regulators of regeneration.


<em>Abstract.</em>—Because of their tendency to accumulate in estuaries and coastal regions, organochlorine (OC) contaminants such as pesticides and polychlorinated biphenyls (PCBs) represent potential threats to the quality of essential fish habitat for many shark species. These compounds pose special risks to immature sharks in particular because of their ability to impair growth and sexual maturation in juvenile fish at environmentally relevant levels of exposure. In order to assess the extent of these risks in shark populations on the East Coast of the United States, the present study examined concentrations of 30 OC pesticides/pesticide metabolites and total PCBs in juvenile sandbar <em>Carcharhinus plumbeus </em>and blacktip <em>C. limbatus </em>sharks from seven major nursery areas in the western Atlantic Ocean and eastern Gulf of Mexico. Quantifiable levels of PCBs and 13 OC pesticides/ pesticide metabolites were detected via gas chromatography and mass spectrometry in liver of 25 young-of-the-year blacktip sharks from the southeastern U.S. Atlantic coast and three regions on Florida’s gulf coast: Cedar Key, Tampa Bay, and Charlotte Harbor. Similarly, quantifiable levels of PCBs and 14 OC pesticides/metabolites were detected in 23 juvenile <em>C. plumbeus </em>from three sites on the northeastern U.S. coast: middle Delaware Bay, lower Chesapeake Bay, and Virginia’s eastern shore. Liver OC concentrations in Atlantic sandbar and blacktip sharks were higher than expected and, in some cases, comparable with elevated levels observed in deep-sea and pelagic sharks. Although significantly lower than those observed in Atlantic sharks, pesticide and PCB levels in Florida blacktip sharks were similar to, if not greater than, OC concentrations reported in adults of other coastal shark species. Based on these data, OC contamination appears to pose significant threats to habitat quality in sandbar and blacktip shark nursery areas on the U.S. Atlantic coast.


2019 ◽  
Vol 160 (4) ◽  
pp. 1087-1095 ◽  
Author(s):  
Nathalie Kürten ◽  
Oscar Vedder ◽  
Jacob González-Solís ◽  
Heiko Schmaljohann ◽  
Sandra Bouwhuis

2019 ◽  
Vol 30 (2) ◽  
pp. 311-337 ◽  
Author(s):  
Wesley D. Stoner ◽  
Deborah L. Nichols

AbstractWe explore the relationship between long-distance pottery trade and the formation of Early and Middle Formative style horizons in Mesoamerica. A sample of 1,154 ceramics mostly from Early and Middle Formative contexts in the central Mexican highlands was irradiated at the University of Missouri Research Reactor with a subsample (n = 313) for petrographic analysis. We conclude that: (1) most sites and regions display more than one process for making pottery; (2) there is a small amount of intraregional exchange among central Mexican sites, with the southeastern Basin of Mexico making the largest portion of pottery intended for trade within the region; and (3) interregional imports found at several sites likely come from the metamorphic region of southwestern Puebla with smaller numbers imported from the southern Gulf Coast, Morelos, and possibly Oaxaca. The trend over time from Early Formative to the end of the Middle Formative is one of decreasing intensity of long-distance interaction and decreasing geographic range of trade. These two trends contribute to the regional divergence of ceramic styles that peaks by the Late Formative in Mesoamerica.


2018 ◽  
Vol 47 (3) ◽  
pp. 654-667 ◽  
Author(s):  
Weipeng Li ◽  
Wentao Xu ◽  
Jin Xie ◽  
Shouyun Yu ◽  
Chengjian Zhu

In the past three years, we have witnessed the rapid development of C–C and C–H bond functionalization by means of long-distance radical migration events which bring us a new platform to deal with the challenging C–C and C–H bond functionalization.


2018 ◽  
Vol 285 (1886) ◽  
pp. 20181656 ◽  
Author(s):  
Jonathan Okerblom ◽  
William Fletes ◽  
Hemal H. Patel ◽  
Simon Schenk ◽  
Ajit Varki ◽  
...  

Compared to other primates, humans are exceptional long-distance runners, a feature that emerged in genus Homo approximately 2 Ma and is classically attributed to anatomical and physiological adaptations such as an enlarged gluteus maximus and improved heat dissipation. However, no underlying genetic changes have currently been defined. Two to three million years ago, an exon deletion in the CMP-Neu5Ac hydroxylase ( CMAH ) gene also became fixed in our ancestral lineage. Cmah loss in mice exacerbates disease severity in multiple mouse models for muscular dystrophy, a finding only partially attributed to differences in immune reactivity. We evaluated the exercise capacity of Cmah −/− mice and observed an increased performance during forced treadmill testing and after 15 days of voluntary wheel running. Cmah −/− hindlimb muscle exhibited more capillaries and a greater fatigue resistance in situ . Maximal coupled respiration was also higher in Cmah null mice ex vivo and relevant differences in metabolic pathways were also noted. Taken together, these data suggest that CMAH loss contributes to an improved skeletal muscle capacity for oxygen use. If translatable to humans, CMAH loss could have provided a selective advantage for ancestral Homo during the transition from forest dwelling to increased resource exploration and hunter/gatherer behaviour in the open savannah.


2020 ◽  
Vol 13 (1-2) ◽  
pp. 10-17
Author(s):  
Young-Min Moon ◽  
Kwanmok Kim ◽  
Jinhan Kim ◽  
Hwajung Kim ◽  
Jeong-Chil Yoo

Stable isotopes are well documented as effective intrinsic markers to infer migratory connectivity which provides key information for establishing an effective conservation strategy in migratory birds. However, there are few studies using stable isotopes that have been applied to long-distance migratory shorebirds globally and such studies are especially scarce along the East Asian–Australasian Flyway. We used stable isotope analysis (δ2H, δ13C and δ15N) to infer breeding and wintering areas and examine the differences in those values among populations of Terek Sandpipers ( Xenus cinereus) at stopover sites in South Korea. The range of δ2H in feathers sampled from birds caught in the Korean peninsula at spring and autumn migration stopover sites was consistent with them being grown at sites throughout their flyway as confirmed by leg flag resightings of birds on this flyway. The eastern Siberia region from Yakutsk to Norilsk and Chukotka in Russia was inferred as the most probable breeding area of the population. Papua New Guinea in the Melanesia region, Malaysia and Indonesia were identified as the most probable wintering areas. Isotope values of populations at different stopover sites and different seasons were consistent. These results suggest that stable isotopes can be effectively used alongside other existing methods (e.g. ringing, coloured leg flags, light level geolocation, satellite tag telemetry) to infer the migratory connectivity for long-distance migratory shorebird species that occur over many countries and continents.


2009 ◽  
Vol 72 (10) ◽  
pp. 2110-2113 ◽  
Author(s):  
ANGELO DePAOLA ◽  
JESSICA L. JONES ◽  
KATHY E. NOE ◽  
ROBIN H. BYARS ◽  
JOHN C. BOWERS

From June through October 2004, the U.S. Food and Drug Administration collected oysters (61 samples) that had been subjected to postharvest processing (PHP) methods, including mild heat treatment, freezing, and high hydrostatic pressure, from processors and retail markets in various states to determine Vibrio vulnificus and V. parahaemolyticus levels. Presence in a 25-g sample and most probable number (MPN) using standard enrichment and selective isolation procedures were utilized. Suspect colonies were isolated and identified using DNA probe colony hybridization. Neither species of vibrio was detected in 25-g portions of most samples regardless of the PHP. The lowest frequency of isolation of either pathogen (&lt;10%) was observed with the mild heat process. Few (12 to 13%) frozen samples collected at the processor but not at retail contained &gt;30 MPN/g of either pathogen. The mean levels of either organism in PHP oysters observed in the present study were 5 to 6 log less than in unprocessed raw Gulf Coast oysters. Of the 70 V. vulnificus isolates examined, only 5 possessed the putative virulence marker, type B 16S rRNA. Neither the thermostable direct hemolysin (tdh) nor the tdh-related hemolysin (trh) virulence gene was detected in any of the 40 V. parahaemolyticus isolates examined in the present study. These data suggest that if there is any selective advantage to pathogenic strains of V. vulnificus and V. parahaemolyticus, these differences are minimal. These results indicate that all PHP treatments greatly reduce exposure of V. vulnificus and V. parahaemolyticus to raw-oyster consumers. Consequently, these PHP oysters pose a much lower risk of illness to consumers due to these pathogens.


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