Browsing by Author "Senner, Nathan"
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- Data packageData from: Compensation for wind drift prevails for a shorebird on a long-distance, transoceanic flight(2023-04-19) Linscott, Jennifer A.; Navedo, Juan G.; Clements, Sarah J.; Loghry, Jason P.; Ruiz, Jorge; Ballard, Bart M.; Weegman, Mitch D.; Senner, NathanBackground: Conditions encountered en route can dramatically impact the energy that migratory species spend on movement. Migratory birds often manage energetic costs by adjusting their behavior in relation to wind conditions as they fly. Wind-influenced behaviors can offer insight into the relative importance of risk and resistance during migration, but to date, they have only been studied in a limited subset of avian species and flight types. We add to this understanding by examining in-flight behaviors over a days-long, barrier-crossing flight in a migratory shorebird. Methods: Using satellite tracking devices, we followed 25 Hudsonian godwits (Limosa haemastica) from 2019–2021 as they migrated northward across a largely transoceanic landscape extending > 7000 km from Chiloé Island, Chile to the northern coast of the Gulf of Mexico. We identified in-flight behaviors during this crossing by comparing directions of critical movement vectors and used mixed models to test whether the resulting patterns supported three classical predictions about wind and migration. Results: Contrary to our predictions, compensation did not increase linearly with distance traveled, was not constrained during flight over open ocean, and did not influence where an individual ultimately crossed over the northern coast of the Gulf of Mexico at the end of this flight. Instead, we found a strong preference for full compensation throughout godwit flight paths. Conclusions: Our results indicate that compensation is crucial to godwits, emphasizing the role of risk in shaping migratory behavior and raising questions about the consequences of changing wind regimes for other barrier-crossing aerial migrants.
- Data packageData from: Kiawah and Seabrook islands are a critical site for the rufa Red Knot (Calidris canutus rufa)(2022-12-13) Pelton, Mary Margaret; Padula, Sara R.; Garcia-Walther, Julian; Andrews, Mark; Mercer, Robert; Porter, Ron; Sanders, Felicia; Thibault, Janet; Senner, Nathan; Linscott, Jennifer A.The rufa Red Knot Calidris canutus rufa is a migratory shorebird that performs one of the longest known migrations among birds and has experienced a population decline of over 85% in recent decades. During migration, rufa Red Knots rest and refuel at stopover sites along the Atlantic Coast of the USA, including Kiawah and Seabrook islands in South Carolina. We document the importance of Kiawah and Seabrook islands forknots during their spring migration using on-the-ground surveys between 19 February and 20 May 2021 to record the occurrence and proportion of individually marked knots, as well as geolocators deployed on knots captured in the area. Using a superpopulation model, we estimated a minimum passage population of 17,247 knots (95% CI: 13,548–22,099; ~41% of the total rufa knot population) and an average stopover duration of 47 days (95% CI: 40.1–54.8). Our geolocator results showed that knots using Kiawah and Seabrook islands can bypass Delaware Bay and fly directly to the Canadian Arctic. Finally, our geolocators, combined with resighting data from across the Atlantic Flyway, indicate that a large network of more than 70 coastal sites concentrated largely in the southeastern USA provide stopover and overwintering habitat for the knots we observed on Kiawah and Seabrook islands. These findings show that Kiawah and Seabrook islands should be recognized as critical sites in the knot network and, therefore, a conservation priority. The threats facing these sites, such as prey depletion, anthropogenic disturbance, and sea level rise, require immediate attention.
- Data packageData from: When Siberia came to The Netherlands: the response of continental black-tailed godwits to a rare spring weather event(2015-05-13) Senner, Nathan; Verhoeven, Mo; Abad-Gómez, José Maria; Gutiérrez, Jorge; Hooijmeijer, Jos; Kentie, Rosemarie; Masero, Jose; Tibbitts, T.; Piersma, Theunis1. Extreme weather events have the potential to alter both short- and long-term population dynamics as well as community- and ecosystem-level function. Such events are rare and stochastic, making it difficult to fully document how organisms respond to them and predict the repercussions of similar events in the future. 2. To improve our understanding of the mechanisms by which short-term events can incur long-term consequences, we documented the behavioural responses and fitness consequences for a long-distance migratory bird, the continental black-tailed godwit Limosa limosa limosa, resulting from a spring snowstorm and three-week period of record low temperatures. 3. The event caused measurable responses at three spatial scales—continental, regional, and local—including migratory delays (+19 d), reverse migrations (>90 km), elevated metabolic costs (+8.8% maintenance metabolic rate), and increased foraging rates (+37%). 4. There were few long-term fitness consequences, however, and subsequent breeding seasons instead witnessed high levels of reproductive success and little evidence of carry-over effects. 5. This suggests that populations with continued access to food, behavioural flexibility, and time to dissipate the costs of the event can likely withstand the consequences of an extreme weather event. For populations constrained in one of these respects, though, extreme events may entail extreme ecological consequences.