Biology subjects

Jiguet, F.

Publications and source records attributed to Jiguet, F..

4 recordsLinked to original sources

bioRxiv2025

Gradual ontogenetic shifts in the mobility and space use of long-lived migratory greater flamingos

O_LIHow early-life exploration shapes the adult annual cycle routines of migratory animals remains challenging to study, especially in long-lived species. Delayed recruitment often observed in long-lived migratory birds suggests that the first breeding attempt may be constrained by a protracted learning process in which individuals develop their annual itinerary, which may involve extensive exploration of the winter and breeding sites, potentially causing inexperienced young to wander beyond traditional population areas. C_LIO_LIUsing greater flamingo Phoenicopterus roseus GPS tracking data from 83 individuals tagged as nestlings in the Mediterranean, we analyzed ontogenetic changes in mobility and space use for up to 8 years of age. We segmented autumn-winter and spring-summer tracks (n = 223 device-bird-year combinations) into staging events (n = 1914). We then computed seasonal staging metrics and analysed how they changed with age. We map the traditional congregation sites of flamingos to investigate age-related changes in space use between males and females. C_LIO_LIFlamingos were more exploratory during their early years, gradually transitioning to a more sedentary lifestyle as they grew older. With each additional year of age, the number of staging events decreased by 16%, while the average duration of staging events increased by 8 days. C_LIO_LIBirds remained faithful to the non-breeding staging sites where they spent most of their time during the first year of life. Over time, they returned progressively closer to their natal sites, even after years of exploration at non-traditional locations. Breeding was rare (8%) and occurred at a relatively late age ([≥]5 years), highlighting an extended exploratory phase, a pattern observed in other long-lived species. C_LIO_LIOlder birds were more likely to use traditional sites and spent more time at these sites, particularly after age 5. Our study reveals the individual exploration process underlying natal and non-breeding dispersal patterns previously laid bare by ring-resighting studies and shows that flamingos retain long-term memory of sites learned in early life. C_LI

ecology↗

bioRxiv2024

Variations in flight strategy of small migratory birds crossing major ecological barriers

The recent development of tracking technologies has revealed remarkable diel flight altitude changes over the Sahara Desert in small migratory bird species. However, the drivers and the traits that explain these crossing strategies remain poorly understood in part because so few species and barriers have been studied. Using a unique dataset from 67 recovered multi-sensor loggers, deployed across 17 species, we investigated when, where, and how birds cross two major marine barriers (Bay of Biscay, Mediterranean Sea) and a desert barrier (Sahara). Then, we relied on a comparative approach to examine the influence of wing morphology and plumage colour on these strategies. Our findings reveal important differences across barrier types. On average, birds fly at 1,600 m over the desert during nighttime, ascending to 2,800 m for prolonged daytime flights, while species crossing marine barriers fly significantly lower (750 m on average), in some cases flying just above the water surface during prolonged daytime flights. Wing morphology and plumage colour influence barrier-crossing strategies: flight altitude increases with wing area during both sea and desert crossings, and darker birds ascend to higher elevations during daytime Sahara crossings, likely to access cooler air and reduce solar heating. These findings refine hypotheses on barrier-crossing strategies and suggest broader ecological and evolutionary implications for migratory birds facing extreme environments.

ecology↗

bioRxiv2023

Migration routes and wintering sites of the Aquatic Warblers Acrocephalus paludicola breeding in Lithuania and North Belarus

For the effective protection of the globally threatened Aquatic Warbler in its entire range, knowledge of the migration and wintering areas as well as their current conservation status is of great importance. The question on where the different breeding population overwinter where (connectivity) equally important. This is also essential when new breeding populations are re-established in restored breeding sites through translocation from other, distant areas, as recently performed in Lithuania. From previous geolocator studies in central Ukraine and south-western Belarus, as well as from ringing data, it was known that these populations overwinter in Mali (Inner Niger Delta IND) and southern Mauritania. In addition, at least some birds of the NE-Polish breeding population overwinter in the Senegal delta (ring recovery). In 2018 and 2019, the migratory routes, stopover and wintering sites of two breeding populations at the north-western distribution range border in N-Belarus (29 males) and Lithuania (31 males) were investigated using light-level geolocators. All 19 recovered data loggers recorded almost complete annual cycles from mid-July to at least early April. Migration and overwintering sites of both populations did not differ significantly. Most (16 out of 19) birds also spent the winter in the Inner Niger Delta and surrounding wetlands within and around Mali. Only one bird from Belarus hiberbated in the Senegal Delta. One of the Lithuanian birds overwintered in northern Burkina Faso, another northern Nigeria. In addition, important details about the course of migration routes, timing and resting areas could be obtained. For example, the outstanding importance of Morocco and northern Algeria as resting areas on spring migration became obvious. The investigations applying geolocators resulted in a very complex and differentiated picture of the migration and stopover pattern of adult male Aquatic Warblers.

zoology↗

bioRxiv2023

Geographic distribution of feather δ34S in Europe

Geographic distribution models of environmental stable isotopes (so called isoscapes) are widely employed in animal ecology, wildlife forensics and conservation. However, the application of isoscapes is limited to elements and regions for which the spatial patterns have been estimated. Here, we focused on the ubiquitous yet less commonly used stable sulfur isotopes ({delta}34S). To predict the European{delta} 34S isoscape, we used 242 feather samples from Eurasian Reed Warbler (Acrocephalus scirpaceus) formed at 69 European wetland sites. We quantified the relationships between sample{delta} 34S and environmental covariates using a random forest regression model and applied the model to predict the geographic distribution of{delta} 34S. We also quantified within-site variation in{delta} 34S and complementarity with other isotopes on both individual and isoscape levels. The predicted feather{delta} 34S isoscape shows only slight differences between the central and southern parts of Europe while the coastal regions were most enriched in 34S. The most important covariates of{delta} 34S were distance to coastline, surface elevation and atmospheric concentrations of SO2 gases. The absence of a systematic spatial pattern impedes the application of the{delta} 34S isoscape but high complementarity with other isoscapes advocates the combination of multiple isoscapes to increase precision of animal tracing. Feather{delta} 34S compositions showed considerable within-site variation with highest values in inland parts of Europe, likely attributed to wetland anaerobic conditions and redox sensitivity of sulfur. The complex European geography and topography as well as using{delta} 34S samples from wetlands may contribute to the absence of a systematic spatial gradient of{delta} 34S values in Europe. We thus encourage future studies to focus on the geographic distribution of{delta} 34S using tissues from diverse taxa collected in various habitats over large land masses in the world (i.e., Africa, South America or East Asia). Open Research statementSample metadata are stored and available for reuse in the AviSample Network database (https://avisample.net/: AS00001-AS00117; Brlik et al. 2022b). The information on the isotopic composition and geographic origin of feather samples used to produce the{delta} 34S isoscape, predicted feather{delta} 34S,{delta} 2H and{delta} 13C isoscapes are publicly available from the Zenodo data repository at https://doi.org/10.5281/zenodo.7315567 (Brlik et al. 2022c).

ecology↗