Metabolic plasticity for subcutaneous fat accumulation in a long-distance migratory bird traced by 2 H 2 O

The migrant black-tailed godwit (Limosa limosa) traditionally used natural wetlands in the Iberian Peninsula to prepare for migratory flights by feeding mainly in estuaries. In recent decades, this species has become increasingly dependent on rice fields, thereby relying on a plant-based diet for fuelling. Dietary fatty acids (FA) seem to be determinant to the composition of accumulated subcutaneous fat in migratory birds. It is still unclear whether metabolic plasticity allows for modification and/or synthesis of FA, contributing to a lipid profile that enables a successful migratory performance. Deuterated water was administered to captive black-tailed godwits submitted to two diets (fly larvae versus rice) and the incorporation of deuterium (2H) into subcutaneous triglycerides was analyzed by NMR. A recently developed localized biopsy method for sampling subcutaneous fat was employed with later successful release of all birds into the wild. The average chemical structure reflected mostly a mixture of saturated and monounsaturated 16- and 18-carbon FA, a profile frequently found in migrant birds. Significantly higher levels of polyunsaturated FA, as well as detectable levels of n-3 FA, were observed in fly-larvae-fed birds. Excess 2H-enrichments in FA revealed significantly higher rates of fractional de novo lipogenesis and FA desaturation capacity in rice-fed birds. This novel and non-lethal tracer method revealed the capacity of this species to alter its lipid metabolism to compensate for a poorer dietary lipid contribution. Because of its versatility, adapting this method to other scenarios and/or other migratory species is considered feasible and cost-effective.The authors acknowledge financial support from Fundacao para a Ciencia e Tecnologia (FCT) in the form of fellowships to I.V. (SFRH/BPD/90032/2012), P.M.A. (SFRH/BD/69238/2010), A.D.R. (SFRH/BD/74228/2010) and J.A.A. (SFRH/BPD/91527/2012) and research project EXCL/DTP-PIC/0069/2012. NMR data were collected at the UC-NMR facility that is supported by FEDER and FCT (RECI/QEQ-QFI/0168/2012, CENTRO-07-CT62-FEDER-002012) and Rede Nacional de Ressonancia Magnetica Nuclear (RNRMN).Peer Reviewe

Understanding how birds rebuild fat stores during migration: insights from an experimental study

Publisher's version (útgefin grein).Mechanisms underlying fat accumulation for long-distance migration are not fully understood. This is especially relevant in the context of global change, as many migrants are dealing with changes in natural habitats and associated food sources and energy stores. The continental Black-tailed godwit Limosa limosa limosa is a long-distance migratory bird that has undergone a considerable dietary shift over the past few decades. Historically, godwits fed on an animal-based diet, but currently, during the non-breeding period godwits feed almost exclusively on rice seeds. The latter diet may allow building up of their fuel stores for migration by signifcantly increasing de novo lipogenesis (DNL) activity. Here, we performed an experiment to investigate lipid fux and the abundance of key enzymes involved in DNL in godwits, during fasting and refueling periods at the staging site, while feeding on rice seeds or fy larvae. Despite no signifcant diferences found in enzymatic abundance (FASN, ME1, ACC and LPL) in stored fat, experimental godwits feeding on rice seeds presented high rates of DNL when compared to fy-larvae fed birds (~35 times more) and fasted godwits (no DNL activity). The increase of fractional DNL in godwits feeding on a carbohydrate-rich diet can potentially be enhanced by the fasting period that stimulates lipogenesis. Although requiring further testing, these recent fndings provide new insights into the mechanisms of avian fat accumulation during a fasting and refueling cycle and associated responses to habitat and dietary changes in a migratory species.Te authors acknowledge fnancial support from Fundação para a Ciencia e Tecnologia (FCT) in the form of fellowships to PMA (SFRH/BD/69238/2010), IV (SFRH/BPD/90032/2012) and JAA (SFRH/BPD/91527/2012) and research Project CGL2017-89009-P. NMR data were collected at the UC-NMR facility that is supported by FEDER and FCT (RECI/QEQ-QFI/0168/2012, CENTRO-07-CT62-FEDER-002012) and Rede Nacional de Ressonancia Magnética Nuclear (RNRMN). Tis study benefted from funding by the strategic program of MARE, fnanced by FCT (UID/MAR/04292/2019), and by FTC/MCTES to CESAM, (UID/AMB/50017 – POCI01-0145-FEDER-007638), through national funds.Peer Reviewe

A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds

The Numeniini is a tribe of thirteen wader species (Scolopacidae, Charadriiformes) of which seven are near-threatened or globally threatened, including two critically endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian - Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species

Dual function of egg-covering in the Kentish plover Charadrius alexandrinus

Many bird species take recesses during incubation, and while the nests are unattended, the eggs may both be vulnerable to predation and reach suboptimal temperatures for embryo development. Perhaps to avoid these negative possibilities, some birds cover their eggs with materials when they depart from nests. We examined experimentally, using the ground-nesting Kentish plover as model species, whether egg-covering allows egg temperatures to remain within optimal limits for embryogenesis in unattended nests, thus reducing the requirements of contact incubation, and simultaneously maintain the eggs' camouflage. There was a negative relationship between nest attendance and ambient temperature, but only during mid-morning, the period of the day when egg-covering was most frequent. Indeed, during mid-morning egg-covering not only served to better camouflage the eggs, but also to maintain egg temperatures within optimal thermal thresholds for embryogenesis while the nests remained unattended. During other periods of the day, covered eggs in unattended nests overheated (e.g., afternoon) or did not reach the optimal temperature for embryogenesis (e.g., early morning). During periods in which eggs may be uncovered to alleviate overheating, unattended nests may be easier to locate by predators, because the eggs are less well camouflaged. Therefore, camouflage and appropriate thermal environment are inseparable functions of egg-covering in the ground-nesting Kentish plover.Direccion General de Investigacion Cientifica y TecnicaDireccion General de Investigacion Cientifica y Tecnica [PB95-0110]Ministerio de Ciencia e Innovacion, SpainMinisterio de Ciencia e Innovacion, Spain [CGL2011-24230]EUERDFEU-ERD

Data from: Identifying management actions to increase foraging opportunities for shorebirds at semi-intensive shrimp farms

The expansion of aquaculture has resulted in widespread habitat conversion throughout the world. Identifying beneficial management measures may dramatically reduce negative impacts of aquaculture for migratory birds. We studied how densities of foraging shorebirds varied at ponds within a semi-intensive shrimp aquaculture farm on the north-western coast of Mexico, as related to timing of harvest and tidal cycles. Further, we estimated the total daily available area for each shorebird species throughout two entire harvesting seasons at the shrimp farm. High densities (average ca. 50 individuals per ha) of foraging shorebirds were found during the first days following pond harvest. The most abundant species were Willet Tringa semipalmata and Black-necked Stilt Himantopus mexicanus, followed by Marbled Godwit Limosa fedoa and American Avocet Recurvirostra americana. Other regular, but less abundant, species were whimbrel Numenius phaeopus and dowitchers Limnodromus spp. Densities of shorebirds sharply declined daily following harvest. In addition, the time-window availability of harvested ponds was related to each species' foraging behaviour: <2 days for godwits and dowitchers, 4 days for stilts, 5 days for willets and more than a week for avocets and whimbrels. However, birds continued to use harvested ponds that received a low, but continuous water influx. Our results demonstrate that a tropical shrimp farm represents a patchy environment that provides 4·3–12·7% (depending on species) of its total area as foraging opportunities for shorebirds. Synthesis and applications. Sequential harvesting of shrimp aquaculture farm ponds and increasing moisture of the substrate by providing some water supply to harvested ponds, at least throughout the harvesting period, could integrate shorebird conservation into shrimp-farm production. These low-cost and easy management procedures would not increase costs or affect shrimp production – thus representing a win-win opportunity – and would have potential applications for shorebird conservation throughout the world

Verhoeven et al._Generational shift_Brood succes females

Data on brood success of females in the Haanmeer polde

Verhoeven et al._Generational shift_FigS1_Extremadura

Data on proportion resighted in Spain (Figure S1A

Generational shift in spring staging site use by a long-distance migratory bird

In response to environmental change, species have been observed altering their migratory behaviours. Few studies, however, have been able to determine whether these alterations resulted from inherited, plastic or flexible changes. Here, we present a unique observation of a rapid population-level shift in migratory routes—over 300 km from Spain to Portugal—by continental black-tailed godwits Limosa limosa limosa. This shift did not result from adult godwits changing staging sites, as adult site use was highly consistent. Rather, the shift resulted from young godwits predominantly using Portugal over Spain. We found no differences in reproductive success or survival among individuals using either staging site, indicating that the shift resulted from developmental plasticity rather than natural selection. Our results therefore suggest that new migratory routes can develop within a generation and that young individuals may be the agents of such rapid changes