Post-breeding Season Research Articles

Comparing spatial differences in behavioral pattern transition of Black-tailed gull during post breeding season in the Korean peninsula

Parents adjust their foraging effort according to the chick and their own body condition and dual foraging strategy is one of the foraging tactics parents replenish their own reserves while feeding their chicks. During the post-breeding season, seabirds disperse to recover their own body condition and prepare for the next breeding season. Recently, we discovered Black-tailed gulls (Larus crassirostris) breeding around the Korean Peninsula occasionally foraging long trips during the late fledging, however, our understanding of the behavioral patterns of Black-tailed gulls during the late fledging and post-breeding, as well as its inter-colonial differences, remains considerably limited. Here, we employed 92 GPS trackers to adult Black-tailed gulls (Larus crassirostris) from six breeding colonies around the Korean peninsula (Yellow Sea—three colonies, South Sea—one colony, and East Sea—two colonies). To determine the foraging investment during the fledging, we suggested the flight efficiency in each trip as the ratio of maximum foraging distance (i.e., straight line distance) to total foraging distance (i.e., sum of all consecutive distance for each trip). Overall, the mean flight efficiency of the long foraging trips were lower than 57% (40.76 ± 13.07%) whereas that of the short foraging trips were over 74% (80.87 ± 4.03%). This may suggest that Black-tailed gulls may visited more than one foraging site during the long foraging trip while they flew directly between the foraging site and breeding colony during the short foraging trip to invest more in their juvenile. Moreover, longer maximum foraging distance with higher flight efficiency observed in the East Sea may indicate a balance between the costs (such as energy expended during foraging or food competition near breeding sites) and the benefits (quantity and quality of food obtained). Our findings revealed the flight behavior of Black-tailed gulls during the late fledging and post breeding, across six breeding colonies, which have different competition pressures and proximity to foraging site.

Diet of the European Pond Turtle (Emys orbicularis) in Anzali Lagoon (South Caspian Sea)

This study explored the diet and food composition of the European Pond Turtle, Emys orbicularis, population in Anzali Lagoon, located in the South Caspian region. A total of 186 turtles were captured during both the pre- and post-breeding seasons to analyse their stomach contents. The analysis revealed that the diet primarily consisted of Arthropoda (76.2%), followed by Mollusca (12.2%), fish (4.6%), aquatic plant material (6.0%), and Annelida (0.9%). The average number of food items during the breeding season was 14 per sample, which significantly decreased to 2.5 in the post-breeding season. On average, male turtles consumed three food items, while females consumed six during the study period. The Pianka Index indicated a high degree of dietary overlap among males, females, and juveniles. Moreover, the Shannon Index revealed food item diversity values of 1.1 for males, 0.94 for females, and 0.62 for juveniles. These findings suggest that the European Pond Turtle in Anzali Lagoon is an opportunistic feeder, with its diet ranging from carnivorous to omnivorous, depending on environmental conditions, season changes, and food availability.

Comparative study of annual and daily capture-recapture and biometrics of two treecreeper species (Certhia spp.) in the post-breeding season over 23 years in western Hungary

Abstract In this study, we detected and compared changes in the annual and daily captures of the Eurasian (Certhia familiaris) and Short-toed Treecreeper (C. brachydactyla) in the timing of their post-breeding movements, in the length of minimum stopover duration (MSD) in the area, and also in biometrics in western Hungary. The birds were captured and ringed, or recaptured from the end of July to the first weekend of November in all years from 2001 to 2023. The annual captures of both species indicated stable populations in this period, with milder February months having a positive effect on annual captures. There were similarities and differences in the movement strategies and habitat selection of the species. During the post-breeding season, the Eurasian Treecreeper was more strongly associated with the scrubland and forest edge than the Short-toed Treecreeper. There were two autumn capture waves in September and October for the Eurasian Treecreepers and just one in September for the Short-toed Treecreepers, which were primarily consisted of birds captured only once. There were no significant differences in wing length of the three capture intervals (July-August, September, October-November) in either species, which suggests that the dynamics of post-breeding movements cannot be explained on the bases of possible differences in the behavior of sexes, ages, or populations. The proportion of birds captured only once was about double of that of stopovers in both species each year. The average real length of stopover duration in the area for Eurasian Treecreepers was 94.25 days, and 84.31 days for Short-toed Treecreepers. The length of MSD in the area was not significantly associated with wing length and body mass in either species. Individuals of both species did not gain fat stores significantly during post-breeding season.

Assessment of biometrics and stress indicators of the adult Village Weaver birds (Ploceus cucullatus) during breeding and post-breeding seasons in Jos, Nigeria

In this era of climate change, some biological conservationists' concerns are based on seasonal studies that highlight how wild birds' physiological fitness are interconnected with the immediate environment to avoid population decline. We investigated how seasonal biometrics correlated to stress parameters of the adult Village Weavers (Ploceus cucullatus) during breeding and post-breeding seasons of the Weaver birds in Amurum Forest Reserve. Specifically, we explored the following objectives: (i) the seasonal number of birds captured; (ii) whether seasonal baseline corticosterone (CORT), packed cell volume (PCV), and heterophil to lymphocytes ratio (H:L) were sex-dependent; (iii) whether H:L ratio varied with baseline (CORT); (iv) whether phenotypic condition (post-breeding moult) and brood patch varied with baseline (CORT) and H:L ratio; and (v) how body biometrics co-varied birds’ seasonal baseline (CORT), (PCV) and (H:L) ratio. Trapping of birds (May–November) coincided with breeding and post-breeding seasons. The birds (n = 53 males, 39 females) were ringed, morphologically assessed (body mass, wing length, moult, brood patch) and blood collected from their brachial vein was used to assess CORT, PCV and H:L ratio. Although our results indicated more male birds trapped during breeding, the multiple analyses of variance (MANOVA) indicated that the seasonal temperature of the trapping sites correlated (P < 0.05) significantly to baseline (CORT). The general linear mixed model analyses (GLMMs) indicated that the baseline (CORT) also correlated significantly to H:L ratio of the male and female birds. However, PCV correlated significantly to body size of the birds (wing length) and not body mass. Haematological parameters such as the baseline CORT and the H:L ratio as indicators of stress in wild birds. Hence, there is the possibility that the Village Weaver birds suffered from seasonally induced stress under the constrained effect of environmental temperature. Hence, future studies should investigate whether the effect observed is also attributable to other passerine species.

The distinctive morphology of caudal neurosecretory system and its impact on Pampus argenteus throughout the breeding season

The caudal neurosecretory system (CNSS) of teleost is intricately linked to reproduction. This study sought to explore the association between the CNSS and the reproductive cycle of Pampus argenteus. Utilizing microscopy and transmission electron microscopy, we observed the morphological alterations within the CNSS. Furthermore, we quantified the levels of urotensin-I (U-I), urotensin-II (U-II), cortisol, and corticotropin-releasing hormone (CRH) throughout the reproductive process. Findings revealed that Dahlgren cells, distributed along the spinal cord adjacent to the terminal 6 vertebrae of the silver pomfret’s tail, were primarily concentrated within the final 3 vertebrae. The neurohypophysis was characterized by an elongated oval form when viewed laterally and an almost spherical configuration in ventral perspective. Post-breeding season, the average diameters of Type I and Type II Dahlgren cells decreased by 21.8% and 15.44%, respectively (P &amp;lt; 0.05), accompanied by a reduction in neurosecretory granules to merely 60% of their initial pre-reproductive state (P &amp;lt; 0.05). Variations in the serum and gonadal concentrations of U-I, U-II, cortisol, and CRH indicated a significant correlation with gonadal maturation. In summary, the CNSS plays a crucial role in gonadal development, directly or indirectly influencing and modulating the reproductive activities of P. argenteus.

Changes in Flight Altitude of Black-Tailed Gulls According to Temporal and Environmental Differences.

In this study, GPS trackers were attached to black-tailed gulls (Larus crassirostris) breeding on five islands in Republic of Korea during April and May 2021, and their flight frequency, behavioral range, and flight altitude were compared during and after the breeding season. During the breeding season, the flight frequency was lowest on Dongman Island (28.7%), where mudflats were distributed nearby, and the range of activity was narrow. In contrast, it tended to be high on Gungsi Island (52%), where the breeding colony was far from land, resulting in a wider range of activity. Although the flight frequency on Dongman Island increased post-breeding season (42.7%), it decreased on other islands. The mean flight altitude during the breeding season was lowest on Dongman Island and highest on Napdaegi Island. In most breeding areas, the mean flight altitude during the post-breeding season was higher than that during the breeding season. However, the lead flight altitude was lower during the non-breeding season compared to that in the breeding season. The home range expanded after the breeding season, with no significant difference in lead time between the breeding and non-breeding seasons. Our findings reveal that black-tailed gulls exhibit varying home ranges and flight altitudes depending on season and geographical location. As generalists, gulls display flexible responses to environmental changes, indicating that flight behavior adapts to the evolving environment over time and across regions.

Negative effects of the spatial clumping of thermal resources on lizard thermoregulation in a fragmented habitat

In ecosystems threatened by the expansion of croplands, habitat fragmentation and climate change, two of the main extinction drivers, may have thermoregulation-mediated interacting effects on demographic trends of terrestrial ectotherms. We studied the thermal biology of a metapopulation of the widespread Mediterranean lacertid Psammodromus algirus in ten fragments of evergreen or deciduous oak forests interspersed among cereal fields. We obtained thermoregulation statistics (selected temperature range, body and operative temperatures, thermal quality of the habitat, and precision, accuracy, and effectiveness of thermoregulation) that could be compared among fragments and with conspecific populations living in unfragmented habitat. We also measured the selection (use vs. availability) and spatial distribution of sunlit and shaded patches used for behavioral thermoregulation in fragments, and we estimated operative temperatures and thermal habitat quality in the agricultural matrix surrounding the fragments. Variation of the thermal environment was much larger within fragments than among them, and thermoregulation was accurate, precise, and efficient throughout the fragmented landscape; its effectiveness was similar to that of previously studied unfragmented populations. The average distance between sunlit and shaded patches was shorter in deciduous than in evergreen fragments, producing a more clumped distribution of the mosaic of thermal resources. Consequently, in evergreen habitat the cost of thermoregulation was higher, because lizards were more selective in their choice of sunlit sites (i.e. they used sunlit patches closer to shade and refuge than expected at random, and the extent of such selection was larger than at deciduous habitat). Temperatures available in croplands were too high to allow lizard dispersal, at least in the post-breeding season. This result confirms the role of croplands as a thermal barrier that promotes inbreeding and associated fitness losses in isolated fragments, and it forecasts a dark future for populations of forest lizards in agricultural landscapes under the combined effects of habitat fragmentation and global warming.

Influence of Seasonal and Monthly Variation on Blood Serum Total Protein in Ctenopharyngodon idella

This study is serum protein of Ctenopharyngodon idella higher in breeding period. That value in post breeding slightly lower and pre–breathing less more than post breeding season in male. In female serum protein where higher in the post breeding. In the breeding season the serum protein is slightly lower and pre breeding value of serum protein less than breeding period.&#x0D; The mean values of female were higher in the post breathing period 5.65 gm% showing seasonal variation as 4.8 to 6.5 gm%. In the breeding season the mean value were very slightly lower side as were found in post breeding season, this period the mean value were 5.50±0.07gm% with seasonal variation of 4.4 to 6.9gm%. During summer pre breeding period the mean values 4.82±0.05 gm % with there seasonal variation of 4.0 to 5.7 gm%. In Male were higher breeding period as 5.65± 0.03 gm% showing seasonal variation as 4.5 to 6.3 gm %. In post breeding season the mean value was very slightly lower side as were found in breeding season in this period the mean value were 5.62±0.06 gm% with the seasonal variation of 4.5 to6.6gm%. During summer i.e. pre breeding period the mean value were 4.62±0.05gm% with their seasonal variation of 3.2 to5.6 gm%.

Brown bear skin-borne secretions display evidence of individuality and age-sex variation

Scent originates from excretions and secretions, and its chemical complexity in mammals translates into a diverse mode of signalling. Identifying how information is encoded can help to establish the mechanisms of olfactory communication and the use of odours as chemical signals. Building upon existing behavioural and histological literature, we examined the chemical profile of secretions used for scent marking by a solitary, non-territorial carnivore, the brown bear (Ursus arctos). We investigated the incidence, abundance, and uniqueness of volatile organic compounds (VOCs) from cutaneous glandular secretions of 12 wild brown bears collected during late and post-breeding season, and assessed whether age-sex class, body site, and individual identity explained profile variation. VOC profiles varied in the average number of compounds, compound incidence, and compound abundance by age-sex class and individual identity (when individuals were grouped by sex), but not by body site. Mature males differed from other age-sex classes, secreting fewer compounds on average with the least variance between individuals. Compound uniqueness varied by body site and age for both males and females and across individuals. Our results indicate that brown bear skin-borne secretions may facilitate age-sex class and individual recognition, which can contribute towards further understanding of mating systems and social behaviour.

Telemetry and Accelerometer Tracking of Green Toads in an Urban Habitat: Methodological Notes and Preliminary Findings.

Advancements in tracking technologies provide an increasingly important tool in animal monitoring and conservation that can describe animal spatial behavior in native habitats and uncover migratory routes that otherwise may be difficult or impossible to map. In addition, high-resolution accelerometer sensors provide powerful insights into animal activity patterns and can help to identify specific behaviors from accelerometer profiles alone. Previously, such accelerometers were restricted to larger animals due to size and mass constraints. However, recent advances make it possible to use such devices on smaller animals such as the European green toad (Bufotes viridis), the focus of our current study. We deploy custom made tracking devices, that consist of very-high-frequency transmitters and tri-axial accelerometers, to track toads in their native urban environment in Vienna (Austria). A total of nine toads were tracked, ranging from three to nine tracking days per individual during the post-breeding season period. We demonstrate that our devices could reliably monitor toad movement and activity during the observation period. Hence, we confirmed the predominantly nocturnal activity patterns and recorded low overall movement at this urban site. Accelerometer data revealed that toads exhibited brief but intense activity bursts between 10 pm and midnight, resting periods during the night and intermittent activity during the day. Positional tracking alone would have missed the major activity events as they rarely resulted in large positional displacements. This underscores the importance of and value in integrating multiple tracking sensors for studies of movement ecology. Our approach could be adapted for other amphibians or other animals with mass constraints and may become standard monitoring equipment in the near future.

Sex and Season Affect Cortical Volumes in Free-Living Western Fence Lizards, Sceloporus occidentalis

The hippocampus plays an important role in spatial navigation and spatial learning across a variety of vertebrate species. Sex and seasonal differences in space use and behavior are known to affect hippocampal volume. Similarly, territoriality and differences in home range size are known to affect the volume of the reptile hippocampal homologues, the medial and dorsal cortices (MC, DC). However, studies have almost exclusively investigated males and little is known about sex or seasonal differences in MC and/or DC volumes in lizards. Here, we are the first to simultaneously examine sex and seasonal differences in MC and DC volumes in a wild lizard population. In Sceloporus occidentalis, males display territorial behaviors that are more pronounced during the breeding season. Given this sex difference in behavioral ecology, we expected males to have larger MC and/or DC volumes than females and for this difference to be most pronounced during the breeding season when territorial behavior is increased. Male and female S. occidentalis were captured from the wild during the breeding season and the post-breeding season and were sacrificed within 2 days of capture. Brains were collected and processed for histology. Cresyl-violet-stained sections were used to quantify brain region volumes. In these lizards, breeding females had larger DC volumes than breeding males and nonbreeding females. There was no sex or seasonal difference in MC volumes. Differences in spatial navigation in these lizards may involve aspects of spatial memory related to breeding other than territoriality that affect plasticity of the DC. This study highlights the importance of investigating sex differences and including females in studies of spatial ecology and neuroplasticity.

Divergent post-breeding spatial habitat use of Laysan and black-footed albatross

Understanding the at-sea movements of wide-ranging seabird species throughout their annual cycle is essential for their conservation and management. Habitat use and resource partitioning of Laysan (Phoebastria immutabilis) and black-footed (Phoebastria nigripes) albatross are well-described during the breeding period but are less understood during the post-breeding period, which represents ~40% of their annual cycle. Resource partitioning may be reduced during post-breeding, when birds are not constrained to return to the nest site regularly and can disperse to reduce competitive pressure. We assessed the degree of spatial segregation in the post-breeding distributions of Laysan (n = 82) and black-footed albatrosses (n = 61) using geolocator tags between 2008 and 2012 from two large breeding colonies in the Northwestern Hawaiian Islands, Midway Atoll, and Tern Island. We characterized the species-and colony-specific foraging and focal distributions (represented by the 95 and 50th density contours, respectively) and quantified segregation in at-sea habitat use between species and colonies. Laysan and black-footed albatross showed consistent and significant at-sea segregation in focal areas across colonies, indicating that resource partitioning persists during post-breeding. Within breeding colonies, segregation of foraging areas between the two species was more evident for birds breeding at Tern Island. Spatial segregation decreased as the post-breeding season progressed, when spatial distributions of both species became more dispersed. In contrast to studies conducted on breeding Laysan and black-footed albatross, we found that sea surface temperature distinguished post-breeding habitats of black-footed albatrosses between colonies, with black-footed albatrosses from Midway Atoll occurring in cooler waters (3.6°C cooler on average). Our results reveal marked at-sea segregation between Laysan and black-footed albatross breeding at two colonies during a critical but understudied phase in their annual cycle. The observed variation in species-environment relationships underscores the importance of sampling multiple colonies and temporal periods to more thoroughly understand the spatial distributions of pelagic seabirds.

Summer bird populations of burnt bog-forest land of the Kerzhensky Nature Reserve ten years after wildfires (Central Volga region, Russia)

The bird population was monitored during ten years in the Kerzhensky Nature Reserve damaged by severe wildfires in 2010. In the burned territory 126 bird species (120 species in the breeding season) were noted, for which weighted averages of bird abundance were calculated. It was noted that the number of species was increasing gradually in the breeding season. The birds of forest edges and of dry valleys appeared already during the second post-fire year, but their abundance increased only in the third-fourth year. The bird population abundance has increased almost 2 times in the breeding season over ten years, while it has not increased significantly in the post-breeding season. The total biomass and the transformed energy, on the contrary, decreased especially in the post-breeding season. During the first six years Fringilla coelebs Linnaeus, 1758 was the absolute leader at the abundance, and its co-dominant was Anthus trivialis (Linnaeus, 1758), and in last two years Phylloscopus trochilus (Linnaeus, 1758) was the leader. The share of the leaders in the breeding season gradually decreased, and the species diversity and the alignment grew. The birds fed in the breeding season mostly on the soil surface. The share of shrubby species increased by two times a couple of years after the wildfires, and the share of crowns birds increased after another four years. The similarity of the ornithocomplex of the burnt territory in the first and last two years of the research amounted to only 0.63 units (the Sorensen-Chekanovsky index).

Reproductive phase related variations in the expression of neuropeptide, cocaine- and amphetamine- regulated transcript (CART) in the brain and pituitary gland of adult male Microhyla ornata

Cocaine- and amphetamine-regulated transcript (CART) peptide is a multifaceted neuropeptide involved in several physiological functions including appetite and reproduction. While studies in mammals, aves and fishes suggest evolutionary conserved role of CART, the information in amphibian is scanty. We have investigated the reproductive phase related variations of CART in the brain of adult male Microhyla ornata. Seasonal changes in the expression of CART peptide were noticed in the brain and pituitary of M. ornata. Significant differences were observed in the nucleus infundibularis ventralis (NIV), epiphysis (E), anteroventral tegmental region (AV), raphe nucleus (Ra) of the brain and pars intermedia (PI), pars distalis (PD) of the pituitary. Compared to the pre-breeding and post-breeding seasons, increase in CART immunoreactivity was seen in E, NIV, AV, Ra of brain and PI, PD of pituitary gland of animals collected during breeding season. Similarly, highest mRNA levels of CART were also observed in the breeding season in the middle region of brain that includes hypothalamus and pituitary gland. Variation in the levels of CART peptide and mRNA in the brain of M. ornata suggests its conserved role in seasonal control of appetite and reproduction.

Stopover use of a large estuarine wetland by dunlins during spring and autumn migrations: Linking local refuelling conditions to migratory strategies.

Migratory strategies dictate stopover ecology, particularly concerning decisions of when, where and how long to stop, and what to do at stationary periods. In birds, individuals stop primarily to replenish energy stores, although the functions of stopover events vary among and within species, particularly between pre- and post-breeding seasons. Here, we combined plasma metabolite levels and haematological parameters to compare refuelling rates and physiological state within (early, mid, late) and between (spring, autumn) migratory periods, aiming to identify potentially different migratory strategies in a shorebird, the dunlin Calidris alpina, using a key stopover site in Iberia. Plasma triglycerides and β-hydroxybutyrate concentrations did not differ between seasons, and small differences were found in haematological profiles (higher haemoglobin and hematocrit levels in spring). Similar refuelling rates and physiological status suggests a single migratory strategy in spring and autumn. During both seasons, dunlins arrive at the Tagus estuary with medium-to-high fuel loads, indicating they do not engage in prolonged fuelling. This agrees with a skipping migratory strategy, where birds fly short-to-medium distances while fuelling at moderate rates along a network of sites. Although we may expect late spring migrants to experience stronger pressures to optimally schedule migratory events, we found no significant differences in physiological profiles among early, mid and late migrants. Unexpectedly, such differences were found in autumn: early birds showed the highest triglycerides and haemoglobin levels and lowest β-hydroxybutyrate concentrations. These results denote enhanced refuelling rates and blood oxygen-carrying capacity in early autumn migrants, which is typical of jumpers, i.e., birds travelling with larger fuel loads and performing fewer stops. Our study adds substantially to previous knowledge of stopover ecology in migratory shorebirds in the East Atlantic Flyway. Importantly, it indicates that the Tagus estuary is a high-quality stopover site for intermediate fuelling. Yet, understanding non-fuelling stopping functions is needed to ultimately inform conservation planning.

Breeding and Post-Breeding Behavior of the Ghost Bat (Macroderma gigas) at Perth Zoo

Understanding the behavior of wildlife in zoo environments is necessary to determine species’ welfare states and minimize stress whilst optimizing social groupings, particularly where breeding programs are being undertaken. This observational study investigated the behavior and welfare of six groupings of ghost bats (Macroderma gigas) across the breeding and post-breeding seasons within Perth Zoo, Western Australia. Scan sampling was used to record behavioral states and interactions along with spatial preferences within enclosures for 198 hours of observations. A total of 11,895 interval observations were conducted during the study period. Exploratory behavior was correlated with enclosure size, with 18.7% of the total observations in the largest enclosure compared with only 7.1% of them in the smallest enclosure. Male ghost bats engaged in negative behaviors in 40.2% of observed male-male interactions, regardless of the season. Non-breeding females engaged in more female-female negative behaviors during the breeding season, while negative behaviors increased in the breeding female group after the end of the breeding season. This study highlights areas where management practice may be optimized in a zoo setting and provides evidence to consider revising standards of enclosure size for chiropteran species. An increase in heating structures and feeding platforms could also reduce the number of negative interactions between individuals. Given that ghost bats in the wild are listed as Vulnerable, zoo population management and breeding may form an integral part of conservation planning for this species in the near future. As the first published study of zoo-housed ghost bats, these findings help provide insight into the behaviors and interactions of ghost bats in different social groupings across the breeding and post-breeding seasons.

Seasonal Patterns in Daily Flight Distance and Space Use by Great Egrets (Ardea alba)

In an effort to quantify the value of wetland habitats, GPS technology was used to document the movement patterns of 16 Great Egrets (Ardea alba) in North America. Patterns in daily flight distances and utilization distributions (UD; estimates of area occupied on the ground) were documented throughout the annual cycle. Maximum Daily Displacement (MDD), the farthest distance occupied by a bird from colony/roost (central place) in 24 hr was greatest (4.3 ± 0.1 km) during breeding season and lowest (3.3 ± 0.1) during post-breeding season. As birds visited multiple foraging sites and made multiple round trips to central places, this Total Daily Distance (TDD) was also measured. It increased from a mean of about 12 km during the incubation phase to about 35 km at the time of fledging. Average TDD was greatest during breeding season (14.2 ± 0.3 km) and lowest during winter (11.0 ± 0.2 km). The utilization distribution increased from 128 (± 21.3) ha during breeding season to 179 (±32.6) ha during winter. Birds that foraged at tidal sites used 183.3 (± 22.2) ha, twice as much area as birds that foraged strictly in freshwater sites (89.6 ± 21.3 ha).

Foraging Habitat Selection by the Lesser Kestrel Falco naumanni During the Different Phases of Breeding and the Post Breeding Period in Central Greece

The purpose of this study was to evaluate the selection of foraging habitats by the Lesser Kestrel Falco naumanni during the different phases of breeding and the post breeding season on the Plain of Thessaly, central Greece. Foraging habitat selection by the species was recorded by direct visual observation in 2014 and 2015 during their presence in the area. Habitat selection was analyzed using the Savage selectivity index. The results indicate that Lesser Kestrels were likely to positively select fallow and set-aside land from pair formation to the pre-migratory phase, but with some annual variation. Legumes (Alfalfa) and cereals were also positively-selected crop categories, whereas cotton and other kinds of cultivation were significantly avoided. During the incubation and chick rearing phase, cereals (the most widespread form of cultivation in the area), were positively selected, which highlights the importance of these crops during this critical breeding phase. Prey abundance and availability, which depend on farming practices, seem to be the main reasons for the periodic variation in the species' habitat selection in the area.

Successful Long-Distance Breeding Range Expansion of a Top Marine Predator

Little is known about the effects of large-scale breeding range expansions on the ecology of top marine predators. We examined the effects of a recent range expansion on the breeding and foraging ecology of Laysan albatrosses (Phoebastria immutabilis). Laysan albatrosses expanded from historical breeding colonies in the Central Pacific Ocean to the Eastern Pacific Ocean around central Baja California, Mexico, leading to a 4,000-km shift from colonies located adjacent to the productive transition zone in the Central Pacific to colonies embedded within the eastern boundary current upwelling system of the Eastern Pacific California Current. We use electronic tagging and remote sensing data to examine the consequences of this range expansion on at-sea distribution, habitat use, foraging habitat characteristics, and foraging behavior at sea by comparing birds from historic and nascent colonies. We found the expansion resulted in distinct at-sea segregation and differential access to novel oceanographic habitats. Birds from the new Eastern Pacific colony on Guadalupe Island, Mexico have reduced ranges, foraging trip lengths and durations, and spend more time on the water compared to birds breeding in the Central Pacific on Tern Island, United States. Impacts of the range expansion to the post-breeding season were less pronounced where birds maintained some at-sea segregation but utilized similar habitat and environmental variables. These differences have likely benefited the Eastern Pacific colony which has significantly greater reproductive output and population growth rates. Laysan albatrosses have the plasticity to adapt to distinctly different oceanographic habitats and also provide insight on the potential consequences of range shifts to marine organisms.

Home Range and Excursive Post-Breeding Movements of Eurasian Eagle-Owls Revealed by GPS Satellite Transmitters

ABSTRACT Investigating space use of wild birds provides important knowledge of bird behavior and ecology, which is crucial in the management and conservation of threatened species. In the present study, we used GPS satellite telemetry to investigate space use and movements of seven adult Eurasian Eagle-Owls (Bubo bubo) in Norway during breeding and post-breeding seasons. Breeding adults had a mean home range size of 42.9 km2 (SD ± 35.1 km2; 95% kernel density estimation Had hoc), and five individuals performed long (&amp;gt;20 km) excursive movements away from their breeding territories during autumn. Such wide-ranging behavior has not previously been reported for adults of the nominate subspecies B. b. bubo. The study demonstrates the need to investigate seasonal movements of species, populations, and age groups even if they are considered residents, and provides valuable information for management and conservation of the Eurasian Eagle-Owl.