Home range variability and philopatry in Cinereous vultures(Aegypius monachus)breeding in Iberia

Large scavengers are strongly dependent on environmental conditions and carrion distribution and abundance,so season and breeding-related factors may influence the spatial ecology of species such as the Cinereous Vulture(Aegypius monachus),the largest European raptor.Iberia holds one of the biggest populations worldwide,but some aspects of the spatial ecology of the species in this region remain unknown.In this study,17 adult Cinereous Vultures were GPS-tracked in order to study their spatial ecology during the adult phase.The average monthly home ranges(95%Kernel Density Estimation,KDE)and core areas(50%KDE)were 6543±19,935 km^(2)and 1174±4004 km^(2),respectively.The average monthly home range fidelity ranged between 50 and 73%.Differences in movement-related variables between the seasonal periods(incubation,chick-rearing and non-breeding)were found.During the chick-rearing period,the monthly accumulated distance was higher than during the other periods:3316±1108(chick-rearing)vs.1621±622(incubation)vs.1726±1159 km per month(nonbreeding).Additionally,large home range sizes were more frequent during the chick-rearing period.There are two likely causes for these seasonal differences.Firstly,chick-rearing entails a higher energetic expenditure by the parental individuals in foraging activities,so larger movements and foraging areas are expected during this period.Secondly,the flight is favoured during spring and summer due to environmental conditions.Matching chick-rearing and warm months is a great evolutionary advantage for soaring-gliding raptors,as it allows them to cover larger areas with low energy expenditure.Furthermore,six individuals tagged as nestlings highlight the philopatric behaviour of the species:vultures settle their breeding areas 54±51 km from their natal nest(range=9–138 km).

High philopatry rates of Yellow-legged Gulls in the southeastern part of the Bay of Biscay

Background:Philopatry rate is one of the main factors shaping population dynamics in colonial seabirds.Low rates of philopatry are linked to populations with high dispersal,while high rates are linked to populations with a very high spatial structure pattern(i.e.,metapopulations).The Cantabrian Yellow-legged Gull(Larus michahellis)population is considered to be resident,with relatively low dispersal rates.Precise estimations of its philopatry rates are however still lacking.Here,we aimed to estimate philopatry rates in the main Yellow-legged Gull colonies of the province of Gipuzkoa,in the southeastern part of the Bay of Biscay.Methods:We analysed 734 resightings,during the breeding season at the colonies of Getaria,Santa Clara and Ulia,relative to a total of 3245 individuals ringed at birth in these same colonies during a period of 13 years.These data were analysed using Multi-State Recapture models in MARK.Results:After controlling survival and resighting probability,the average dispersal rate among colonies was 4%(±SD=2%)when individuals are immature,decreasing to 1±1%)for adult breeding gulls(i.e.,philopatry rate was 99%).Annual survival rates were assessed to be 0.27±0.02 for birds in their first year of life and 0.87±0.01 for older individuals.The probability of observing immature birds in the colonies was 0.08±0.01,as compared to 0.21±0.02 in adult birds.Conclusions:We obtained evidence of extremely high local philopatry rates,clearly within the upper limit found in gulls.A high philopatry favour a speciation in these species who are vulnerable to obtain the main food source(land-fills and fishing discard)which are transforming under new ecological process.

Extinction of lizards in Sri Lanka’s geographically isolated locations

Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard population will be affected by this phenomenon on a geographical scale.Furthermore,there is a need to establish a connection between extinction risk and the prioritization of conservation efforts.In this context,we aim to address concerns related to geographically isolated and critically small lizard populations,highlighting why they face an exceptionally high risk of extinction.We also explore the potential for entire populations to vanish without notice.A comprehensive understanding of these factors is essential to inform the prioritization of conservation initiatives aimed at safeguarding lizard populations in tropical countries under future climate change scenarios.

Nest site tenacity and mate fidelity in the Black-headed Gull(Chroicocephalus ridibundus)

Breeding philopatry is well known in the Black-headed Gull(Chroicocephalus ridibundus).Using a capture-markrecapture method,we studied if Black-headed Gulls show nest site tenacity and mate fidelity as well,and investigated if there are differences between a stable,and a newly established and fast-growing colony,as well as for differences between the center and edges of these colonies located in north-eastern Germany.We found a high level of nest site tenacity in the center of the stable colony on B?hmke Island,and lower degrees of nest site tenacity at the edge of the same colony and in the newly established and fast-growing colony on Riether Werder.Mate fidelity was very strong in all individuals which returned to their previous breeding place,regardless of the nest site location.