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).

Experimental arena settings might lead to misinterpretation of movement properties

Movement is an important animal behavior contributing to reproduction and survival.Animal movement is often examined in arenas or enclosures under laboratory conditions.We used the red flour beetle(Tribolium castaneum)to examine here the effect of the arena size,shape,number of barriers,access to the arena's center,and illumination on six movement properties.We demonstrate great differences among arenas.For example,the beetles moved over longer distances in clear arenas than in obstructed ones.Movement along the arena's perimeter was greater in smaller arenas than in larger ones.Movement was more directional in round arenas than in rectangular ones.In general,the beetles stopped moving closer to the perimeter and closer to corners(in the square and rectangular arenas)than expected by chance.In some cases,the arena properties interacted with the beetle sex to affect several movement properties.All these suggest that arena properties might also interact with experimental manipulations to affect the outcome of studies and lead to results specific to the arena used.In other words,instead of examining animal movement,we in fact examine the animal interaction with the arena structure.Caution is therefore advised in interpreting the results of studies on movement in arenas under laboratory conditions and we recommend paying attention also to barriers or obstacles in field experiments.For instance,movement along the arena's perimeter is often interpreted as centrophobism or thigmotaxis but the results here show that such movement is arena dependent.

Laboratory-based flight performance of the fall armyworm,Spodoptera frugiperda

In late 2018,the fall armyworm(FAW)Spodoptera frugiperda Smith(Lepidoptera:Noctuidae)made its arrival in China and its populations have since proliferated across most of eastern Asia.While S.frugiperda exhibits a considerable dispersal capacity and engages in long-distance migration,there’s only scant information on the species’flight capability.Here,we empirically assessed S.frugiperda flight activity under varying climatic conditions using a flight mill.More specifically,under laboratory conditions,FAW exhibited superior flight performance at 20-25℃ and 60-90%relative humidity(RH).When quantifying flight performance over five consecutive nights(i.e.,10 h/night),all flight parameters initially increased and then gradually dropped and FAW adults attained a total flight distance,duration and velocity equal to 63.73 km(48.42-94.12 km)(median,quartile range),24.12 h(20.87-27.73 h)and 2.73 km h^(-1)(2.13-3.33 km h^(-1)),respectively.Our work constitutes a first comprehensive assessment of S.frugiperda flight performance and provides baseline information for future efforts to forecast spatiotemporal changes in its geographical distribution,movement patterns and invasion trajectories.Such can ultimately permit a timely and targeted deployment of area-wide pest management measures against this newly-invasive pest in China and across eastern Asia.

Flight activity promotes reproductive processes in the fall armyworm,Spodoptera frugiperda

The fall armyworm(FAW),Spodoptera frugiperda(Lepidoptera:Noctuidae),has invaded many countries in Africa and Asia since 2016,posing a major threat to world food security.Long-distance migration and strong reproductive ability form the biological basis of its rapid population expansion,but the relationship between the flight and reproduction of FAW has not been studied in depth.Here,an empirical assessment of this relationship in an invasive FAW population in China found that 1-3-day-old adults which had undergone 10-h tethered flights had a significantly shorter pre-oviposition period and greater oviposition synchronization,but did not show any differences in fecundity,oviposition period,mating percentage or other reproductive variables.Further studies on moths after 1.25-15-h tethered flights indicated that the reproductive process of adults could be fully triggered by flight activity longer than 2.5 h.Dissection of the reproductive organs also showed that tethered flight promoted ovarian and testicular development of FAW.These results show that appropriate moth flight activity significantly speeds up the reproductive process of FAW,which increases our knowledge on its migratory biology in relation to regional outbreaks.

Migratory flight of insect pests within a year-round distribution: European corn borer as a case study

Insect migratory flight differs fundamentally from most other kinds of flight behavior, in that it is non-appetitive. The adult is not searching for anything, and migratory flight is not terminated by encounters with potential resources. Many insect pests of agricultural crops are long-distance migrants, moving from lower latitudes where they overwinter to higher latitudes in the spring to exploit superabundant, but seasonally ephemeral, host crops. The migratory nature of these pests is somewhat easy to recognize because of their sudden appearance in areas where they had been absent only a day or two earlier. Many other serious pests survive hostile winter conditions by diapausing, and therefore do not require migration to move between overwintering and breeding ranges. Yet there is evidence of migratory behavior engaged in by several pest species that inhabit high latitudes year-round. In these cases, the consequences of migratory flight are not immediately noticeable at the population level, because migration takes place for the most part within their larger year-round distribution. Nevertheless, the potential population-level consequences can be quite important in the contexts of pest management and insect resistance management. As a case study, I review the evidence for migratory flight behavior by individual European corn borer adults, and discuss the importance of understanding it. The kind of migratory behavior posited for pest species inhabiting a permanent distribution may be more common than we realize.

Disturbance increases high tide travel distance of a roosting shorebird but only marginally affects daily energy expenditure

Background:Anthropogenic disturbance can negatively affect an animal's energy budget by evoking movement responses.Existing research focuses mainly on immediate displacement as a disturbance effect,since this can be easily observed in the field. However, effects on movement over longer timescales are poorly examined and it is largely unknown if and to what extent they reflect immediate responses.Longer-term responses could for example be larger than immediate responses if birds, after disturbance, return to the original location and thereby travel twice the immediate disturbed distance. Methods:We combined GPS tracking data with observational data to quantify the effects of anthropogenic (air force and walkers) and non-anthropogenic disturbances on distances travelled by roosting Eurasian Oystercatchers (Haematopus ostralegus) during the non-breeding season. We compared immediate displacement after a disturbance with distance travelled during the entire high tide period (longer-term response), while accounting for environmental factors.Additionally,we calculated energy expenditure due to disturbance based on observed disturbance frequencies.Results:Disturbance resulted in an immediate displacement response of ~200 m (median).Air force disturbances tended to yield larger immediate responses than walker and,especially,than non-anthropogenic disturbances.Longer-term responses and immediate responses were approximately similar,suggesting that,over longer timescales,spatial disturbance effects in the study area remain confined to immediate effects.However,disturbances were infrequent (0.17 disturbances per bird per hour) and most disturbances were of natural origin (62%).Consequently, anthropogenic disturbance of roosting oystercatchers in the study area on average costs 0.08% of the daily energy expenditure. Conclusions:Our results suggest that immediate spatial responses to disturbance can be a useful proxy for spatial responses over longer timescales.Over the non-exhaustive range of conditions investigated,energetic consequences of spatial disturbance responses for an oystercatcher in the study area are marginal due to low disturbance levels.

The role of environmental temperature on movement patterns of giant anteaters

Mammals can show conspicuous behavioral responses to thermal variation,including changes in movement patterns.We used an integrative approach to understand how environmental temperature can drive the movement behavior of a mammal with low capacity for physiological thermoregulation,the giant anteater(Myrmecophaga tridactyla).We tracked 52 giant anteaters in 7 areas throughout the Brazilian savannah.We estimated the distance moved,area used,use of forest areas,and mean environmental temperature for each monitoring day of each individual.We modeled these data with Mixed Structural Equations—considering the possible interactions between our variables and controlling for sex and body mass.Giant anteaters reduced displacement and increased forest use with decreasing environmental temperature,probably because of their low body heat production.It is possible that they reduce distance moved and area used by reducing the duration of activity.With decreasing temperature,forest habitats become warmer than open ones,besides buffer rain and chilly winds.Reducing displacement and using forests are important strategies to reduce body heat loss and the energetic costs of thermoregulation.However,decreasing movement can limit food access and,consequently,fitness.Therefore,we highlight the importance of forests as thermal shelters.With increasing frequency and intensity of extreme weather events,we showed the need to preserve forest patches to offer suitable conditions for tropical mammals’behavioral thermoregulation.In this context,policies favoring deforestation on Brazilian territory are especially worrisome.Finally,we emphasize the need of integrative approaches to understand the complex interactions between organisms and the environment.

The variability of juvenile dispersal in an opportunistic raptor

The juvenile dispersal of raptors is a crucial stage that stretches from parental independence to the establishment of the first breeding area.Between 2012 and 2020,44 juvenile red kites Milvus milvus from the Spanish breeding population were tagged using GPS telemetry to study their dispersal.Juveniles left the parental breeding area at the end of their first summer and performed wandering movements throughout the Iberian Peninsula,returning to the parental breeding area the following year,repeating the same pattern until they settled in their first breeding area.We analyzed the mean distance from the nest,the maximum reached distances,and the traveled distances(daily and hourly)during the first 2 years of dispersal and compared them.Despite the high individual variability,variables describing the dispersal movements of juveniles showed a decreasing trend during the second dispersal year:80% of individuals reached a shorter maximum distance in the second year,70% decreased their mean distance to the nest,65% decreased their hourly traveled distances,and 50% decreased their daily traveled distances.On the other hand,the red kites usually combined wandering movements with the establishment of temporary settlement areas(TSA).The average duration of settlement in the TSAs was 75±40 days(up to 182 days)and was located at 182±168 km from the nest.In those areas,juveniles used 781.0±1895.0 km^(2)(KDE 95%).Some of the TSAs were used by several individuals,which suggests that these areas might be good targets for conservation in future management plans.

Tri-axial accelerometry shows differences in energy expenditure and parental effort throughout the breeding season in long-lived raptors

Cutting-edge technologies are extremely useful to develop new workflows in studying ecological data,particularly to understand animal behavior and movement trajectories at the individual level.Although parental care is a well-studied phenomenon,most studies have been focused on direct observational or video recording data,as well as experimental manipulation.Therefore,what happens out of our sight still remains unknown.Using high-frequency GPS/GSM dataloggers and tri-axial accelerometers we monitored 25 Bonelli’s eagles Aquila fasciata during the breeding season to understand parental activities from a broader perspective.We used recursive data,measured as number of visits and residence time,to reveal nest attendance patterns of biparental care with role specialization between sexes.Accelerometry data interpreted as the overall dynamic body acceleration,a proxy of energy expenditure,showed strong differences in parental effort throughout the breeding season and between sexes.Thereby,males increased substantially their energetic requirements,due to the increased workload,while females spent most of the time on the nest.Furthermore,during critical phases of the breeding season,a low percentage of suitable hunting spots in eagles’territories led them to increase their ranging behavior in order to find food,with important consequences in energy consumption and mortality risk.Our results highlight the crucial role of males in raptor species exhibiting biparental care.Finally,we exemplify how biologging technologies are an adequate and objective method to study parental care in raptors as well as to get deeper insight into breeding ecology of birds in general.

The Ornithodolite as a tool to quantify animal space use and habitat selection: a case study with birds diving in tidal waters

Animal-attached technologies can be powerful means to quantify space use and behavior;however,there are also ethical implications associated with capturing and instrumenting animals.Furthermore,tagging approaches are not necessarily well-suited for examining the movements of multiple individuals within specific,local areas of interest.Here,we assess a method of quantifying animal space use based on a modified theodolite with an inbuilt laser rangefinder.Using a database of>4200 tracks of migrating birds,we show that detection distance in-creases with bird body mass(range 5 g to>10 kg).The maximum distance recorded to a bird was 5500 m and measurement error was≤5 m for targets within this distance range:a level comparable to methods such as GPS tagging.We go on to present a case study where this method was used to assess habitat selection in seabirds operating in dynamic coastal waters close to a tidal turbine.Combining positional data with outputs from a hydrographic model revealed that great cormorants(Phalacrocorax carbo)appeared to be highly selective of current characteristics in space and time,exploiting areas where mean current speeds were<0.8 m∙s^(−1) and diving at times when turbulent energy levels were low.These birds also oriented into tidal currents during dives.Taken together,this suggests that collision risks are low for cormorants at this site,as the 2 conditions avoided by cormorants(high mean current speeds and turbulence levels)are associated with operational tidal turbines.Over-all,we suggest that this modified theodolite system is well-suited to the quantification of movement in small areas associated with particular development strategies,including sustainable energy devices.