Understanding the movement ecology of threatened species is fundamental to improving management and conservation actions for their protection, mainly during the pre-adult stage and particularly when a species is subject to population reinforcement or reintroduction projects. An example is the case of the Cinereous Vulture Aegypius monachus on the Iberian Peninsula, an endangered species that has been reintroduced in different regions during the last two decades. Here, we explore differences between the spatial ecology of reintroduced pre-adult Cinereous Vultures, according to age-class, sex, and season (breeding and non-breeding). We used GPS-tag data from 51 pre-adult individuals reintroduced into Catalonia (north-east Spain) to describe their use of space, i.e. home-range size, core area, and minimum convex polygon (MCP) and movement patterns, i.e. cumulative distance, maximum displacement, maximum daily dispersal, and maximum annual dispersal. Our study showed significant variation in the use of space and movement patterns among pre-adult birds and the influences of age, sex, and season. Age was the most influential factor, determining range areas and movement patterns. Similar to other vulture species, home range and core areas increase with age, with subadult vultures exhibiting larger ranges than young first year, juveniles, and immature birds, but the MCP measures were larger for juveniles. Movement patterns were also influenced by age-class, with juveniles making longer movements, followed by immatures and subadults (with similar values), and shorter movements for birds during their first year of life. Overall, males made shorter movements and explored smaller foraging areas than females. Season had an important effect on movement patterns, and the daily and dispersal movements were longer during the breeding period (February–August). Our findings fill a knowledge gap regarding the dispersal behaviours of Cinereous Vultures, information that will enable the improvement of management and conservation decisions.

Predator-prey interactions are one of the central themes in ecology due to their importance as a key mechanism in structuring biotic communities. In the predator-prey systems, the behaviours of persecution and avoidance impact on the ecosystem dynamics as much as the trophic interactions. We aimed to analyse the spatiotemporal co-occurrences between prey and predators in a community of medium- and large-sized mammals in southern Mexico. We predict prey will avoid sites where a predator previously passed. Contrarily, we expect a search behaviour by predators and a synchronization in activity patterns among them. We found prey does not occur either in time or space where predators have passed, suggesting an avoidance behaviour. Contrary to our expectations, we did not find significant search behaviours from predators to prey. Synchronization in the daily temporal overlap between predators was higher (Δ = 0.77–0.82) than with their prey (Δ = 0.43 – 0.81). The results suggest prey perceives the risk of predation and displays avoidance behaviour both spatially and temporally, which is consistent with the fear theory. This study provides a complementary approach to understanding the behaviour mechanism between predators and prey through camera-trapping or similar data of spatiotemporal co-occurrences.

White-bellied Heron Ardea insignis (WBH) is critically endangered, but we lack data on many aspects of its basic ecology and threats to the species are not clearly understood. The goal of this study was to analyse WBH foraging microhabitat selection, foraging behaviour, and prey preferences in two river basins (Punatsangchhu and Mangdechhu) in Bhutan which are likely home to one of the largest remaining populations of WBH. We also explored the relationship between the relative abundance of the WBH and prey biomass catch per unit effort within four foraging river microhabitats (pool, pond, riffle and run). Prey species were sampled in 13 different 100-m thalweg lengths of the rivers using cast nets and electrofishing gear. Riffles and pools were the most commonly used microhabitats; relative abundance was the highest in riffles. The relative abundance of WBH and prey biomass catch per unit effort (CPUE) also showed a weak but significant positive correlation (rs = 0.22). The highest biomass CPUE was observed in riffles while the lowest was found in the ponds. From the 97 prey items caught by the WBH, 95% of the prey were fish. The WBH mainly exploited three genera of fish (Garra, Salmo, and Schizothorax) of which Schizothorax (64%) was the most frequently consumed. This study provides evidence in support of further protection of critical riverine habitat and fish resources for this heron. Regular monitoring of sand and gravel mining, curbing illegal fishing, habitat restoration/mitigation, and developing sustainable alternatives for local people should be urgently implemented by the government and other relevant agencies. Further study is also required for understanding the seasonal variation and abundance of its prey species in their prime habitats along the Punatsangchhu and Mangdechhu basins.

The spectral tuning properties of the whale shark (Rhincodon typus) rod (rhodopsin or Rh1) and long-wavelength-sensitive (LWS) cone visual pigments were examined to determine whether these retinal pigments have adapted to the broadband light spectrum available for surface foraging or to the narrowband blue-shifted light spectrum available at depth. Recently published whale shark genomes have identified orthologous genes for both the whale shark Rh1 and LWS cone opsins suggesting a duplex retina. Here, the whale shark Rh1 and LWS cone opsin sequences were examined to identify amino acid residues critical for spectral tuning. Surprisingly, the predicted absorbance maximum (λmax) for both the whale shark Rh1 and LWS visual pigments is near 500 nm. Although Rh1 λmax values near 500 nm are typical of terrestrial vertebrates, as well as surface foraging fish, it is uncommon for a vertebrate LWS cone pigment to be so greatly blue-shifted. We propose that the spectral tuning properties of both the whale shark Rh1 and LWS cone pigments are most likely adaptations to the broadband light spectrum available at the surface. Whale shark melanopsin (Opn4) deactivation kinetics was examined to better understand the underlying molecular mechanisms of the pupillary light reflex. Results show that the deactivation rate of whale shark Opn4 is similar to the Opn4 deactivation rate from vertebrates possessing duplex retinae and is significantly faster than the Opn4 deactivation rate from an aquatic rod monochromat lacking functional cone photoreceptors. The rapid deactivation rate of whale shark Opn4 is consistent with a functional cone class and would provide the animal with an exponential increase in the number of photons required for photoreceptor signaling when transitioning from photopic to scotopic light conditions, as is the case when diving.

To understand how foraging decisions impact individual fitness of herbivores, nutritional ecologists must consider the complex in vivo dynamics of nutrient–nutrient interactions and nutrient–toxin interactions associated with foraging. Mathematical modeling has long been used to make foraging predictions (e.g. optimal foraging theory) but has largely been restricted to a single currency (e.g. energy) or using simple indices of nutrition (e.g. fecal nitrogen) without full consideration of physiologically based interactions among numerous co-ingested phytochemicals. Here, we describe a physiologically based model (PBM) that provides a mechanistic link between foraging decisions and demographic consequences. Including physiological mechanisms of absorption, digestion and metabolism of phytochemicals in PBMs allows us to estimate concentrations of ingested and interacting phytochemicals in the body. Estimated phytochemical concentrations more accurately link intake of phytochemicals to changes in individual fitness than measures of intake alone. Further, we illustrate how estimated physiological parameters can be integrated with the geometric framework of nutrition and into integral projection models and agent-based models to predict fitness and population responses of vertebrate herbivores to ingested phytochemicals. The PBMs will improve our ability to understand the foraging decisions of vertebrate herbivores and consequences of those decisions and may help identify key physiological mechanisms that underlie diet-based ecological adaptations.

At-sea behaviour of central-place foraging fur seals and penguins in the Southern Ocean is understudied during the latter stages of parental care and the subsequent pre-moulting period. This biologically important period is costly to investigate due to the risk (or certainty) of losing tracking instruments when the animals moult. Early in this period, parents must meet the increasing demands of larger, more mobile offspring that are still nutritionally dependent and then the parents must recover lost body condition prior to the onset of their annual moult. This study reports late-season, at-sea movement patterns of macaroni penguins, chinstrap penguins and adult female Antarctic fur seals from the subantarctic island Bouvetøya, in relation to remotely-sensed oceanographic features. Foraging trips differing significantly in direction and distance travelled compared to those performed earlier in the breeding season, coincide with the time when offspring would be expected to become independent. On these trips, macaroni penguins moved towards the Polar Front while chinstrap penguins and Antarctic fur seals moved southward. Individuals from all three species appeared to target submesoscale ocean features once they were presumed to have been released from the constraints of feeding their young and were able to travel greater distances from the colony.

The juvenile phase is poorly known in Antarctic seabirds, despite being a critical period for individual survival. To better understand the ecology of young Antarctic seabirds, we surveyed for the first time the three-dimensional habitat use of six juvenile emperor penguins during their post-natal dispersal from Terre Adélie, using bio-telemetric tags. The tags transmitted location and activity data for nearly 100 days on average. One individual was followed during eight months and covered 7000 km, which represents the longest continuous individual survey for the species. Studied individuals first dispersed away from Antarctica, up to 54.7°S and 1250 km north of the pack-ice edge, in the Polar Frontal Zone. This highlighted a much looser association with sea ice and a greater at-sea range compared to previous knowledge on breeding adults. Juvenile penguins then moved southwards close to the extending pack-ice during autumn and winter. Over the survey duration, juveniles showed a contrasting use of marine habitats, with less mobility, less time underwater, and shallower dives (generally not over 50–100 m) in the pack ice, versus greater distances travelled, more time spent underwater, especially deeper than 100 m (up to 250–300 m) in open water. We discuss hypotheses which could explain the northward exodus of juvenile emperor penguins across contrasting habitats.

To assess the impact of habitat fragmentation on tropical avian communities, we sampled lowland forest birds on six land-bridge islands and two mainland forest sites in Lake Kenyir, Peninsular Malaysia using timed point counts, hypothesizing that insectivorous birds are the worst affected guild. We used an information-theoretic approach to evaluate the effects of area, isolation, primary dietary guild (omnivore, frugivore and insectivore) and their interactions in predicting species richness, abundance and diversity. Our analysis showed that a model that considered the effects of area, dietary guild and their interaction best explained observed patterns of species richness. But a model considering both area and dietary guild best explained the variation in abundance. Notably, insectivorous birds were singled out as the dietary guild most sensitive to fragmentation, followed by frugivorous and omnivorous birds and hence provide support for our hypothesis. Assemblages of insectivorous birds were clearly depauperate on anthropogenic forest islands in Lake Kenyir and are consistent with forest fragmentation studies in the Neotropics. Given their specialized foraging ecology and diversity, conservation of intact communities of insectivorous bird guilds in Malaysia will be critical for maintaining predator–prey interactions in lowland tropical forests.

Numerous studies have documented behavioural changes in wildlife because of human disturbance. Disturbance may threaten waders if there are no alternative habitats or foraging times. Here we compared human and dog densities, natural and anthropogenic disturbance rates, prey availability and wader foraging rates at five sites in and around Khao Sam Roi Yod National Park, Thailand, with different shorebird densities, to assess whether disturbance forced wintering waders to under-use high quality sites consistently. We also examined diel and tidal variability in prey densities and tested whether people and dogs cause temporary displacement or reductions in foraging rates. Although there were significant differences in shorebird, human and dog densities as well as anthropogenic disturbance rates and prey availability amongst the five sites, there was no indication that birds were being displaced from the highest quality habitat. There was little diel or tidal variation in most types of prey. People did not temporarily displace waders but did reduce foraging rates. The availability of high quality, alternative foraging habitat with low human disturbance, and nocturnal prey availability, along with the lack of any short-term displacement of birds from areas of high disturbance suggest that disturbance is unlikely to affect wader fitness in this National Park. By examining a range of important habitat characteristics and wader spatial distributions, our study demonstrates a method and a theoretical framework to evaluate the possible impacts of human disturbance on wildlife.

We studied the avian foraging ecology in a single montane forest of northern Kenya, analysing the pattern of seasonal variation (wet vs. dry period) and its relationship with habitat structure. The foraging behaviour of 28 species was described in terms of four major dimensions (i.e. foraging technique, food substrate, perching site and perching height). Seasonal rainfall produced an increase in vegetation growth in the lower vegetation layers, while fruiting and flowering peaked in the dry season. We did not find much seasonal variation in foraging ecology when we analysed our data at the species or at the community levels. At the guild level, however, we found some seasonal shifts in perching height, food substrate and foraging technique. Some of these shifts seemed to be determined by food availability and distribution, as omnivores increased fruit consumption when this resource was more abundant, and nectarivores tracked the vertical distribution of flowers. The vertical biomass distribution of this avian community seemed to be largely determined by food. However, seasonal variation in the total biomass of some guilds was probably related to factors not considered in this study, such as breeding, or intra-African migratory movements. Altogether, despite marked seasonal variation in vegetation structure and food resources, the bird assemblage showed little change in its feeding ecology and micro-habitat use. Hence, we suggest that changes in habitat structure and resource levels were coped with primarily by adjusting population density and food requirements through seasonal breeding or migration.