Spring Breeding Season Research Articles

Auditory risk recognition is socially transmitted across territory borders in wild birds

Prey species commonly assess predation risk based on acoustic signals, such as predator vocalizations or heterospecific alarm calls. The resulting risk-sensitive decision-making affects not only the behavior and life-history of individual prey, but also has far-reaching ecological consequences for population, community, and ecosystem dynamics. Although auditory risk recognition is ubiquitous in animals, it remains unclear how individuals gain the ability to recognize specific sounds as cues of a threat. Here, it has been shown that free-living birds (Wood Warblers Phylloscopus sibilatrix) can learn to recognize unfamiliar, complex sounds (samples of punk rock songs) as cues of a threat from conspecifics holding adjacent territories during the spring breeding season. In a playback experiment, Wood Warblers initially ignored the unfamiliar sounds, but after repeatedly hearing that these sounds trigger alarm calling reaction of neighbors, most individuals showed an anti-predator response to them. Moreover, once learned soon after nestlings hatching, the anti-predator response of parents toward previously unfamiliar sounds was then retained over the entire nestlings rearing period. These results demonstrate that social learning via the association of unfamiliar sounds with known alarm signals enables the spread of anti-predator behavior across territory borders and provides a mechanism explaining the widespread abilities of animals to assess predation risk based on acoustic cues.

Magnitude and persistence of higher estrus-associated temperatures in beef heifers and suckled cows.

Higher estrus-associated temperatures (HEAT) are a hallmark feature in sexually active females. The overarching aim of this study was to characterize the variability, magnitude, and persistence of HEAT in heifers and suckled beef cows as well as identify associated factors when occurring during thermoneutral conditions at the onset of the spring breeding season. In both heifers and cows, estrus was induced using a 7-d controlled internal drug release (CIDR)-PGF2α protocol. Vaginal temperature after prostaglandin F2α administration was recorded every 5min using a Thermochron iButton affixed to a blank CIDR (containing no progesterone). Estrus was defined as when a heifer first stood to be mounted or when a cow had an Estrotect patch score of 3 or 4. Level of HEAT varied among individual animals. When comparing common HEAT variables using a mixed model with date nested within a year, maximum HEAT (39.9 ± 0.1 and 40.0 ± 0.1 °C) and duration (15.5 ± 0.8 and 15.4 ± 0.7) were similar in heifers and cows, respectively. However, the magnitude and persistence of HEAT differed. Total area under the HEAT curve was 117.1 ± 13.5 and 158.7 ± 12.3 for heifers vs cows, respectively (P = 0.0571). Further, 42.9% of heifers and 49% of cows had maximum HEAT ≥ 40 °C which persisted up to 6.5 and 10h, respectively. When ambient conditions were predominantly thermoneutral, temperature humidity index had minimal impact on HEAT (mixed model, repeated measures over time). Toward identifying associated factors with different aspects of HEAT using best fit hierarchical linear regression models, baseline vaginal temperature and baseline duration were the most highly associated independent variables. Follicle size, estradiol and progesterone levels, and other available animal-related variables (e.g., age, weight, hair coat score) explained only a small amount of variation in HEAT. In summary, level of HEAT varies in estrus females even under thermoneutral conditions. Because HEAT can persist for an extended time, direct effects on fertility important components are unavoidable. Whether HEAT is a good or bad component of the periovulatory microenvironment is the basis of ongoing and future studies.

Plainfin Midshipman Fish: Songbirds of the Sea

Most of us have heard birds sing during the spring breeding season. Did you know that some fish also sing to attract mates? We study plainfin midshipman fish, a fascinating fish that makes its home along the Pacific Coast of North America. The big male fish sing during the summer months and their sound-producing muscles get bigger in the summer, probably to make them sound more attractive to females. Female midshipman fish go through seasonal changes, too. In the summer their hearing improves, which helps them pick the right male to mate with. We study hearing in female plainfin midshipman, measuring how their ears respond to sound and how the number of hearing cells in their ears changes between winter and summer. We want to know how seasonal changes in hormones affect hearing in this “songbird of the sea”.

PSIX-26 Reproductive Management Practices for Beef Cow-Calf Producers in Virginia: a Survey

Abstract The Virginia Master Cattlemen (VMC) is an extension program with the goal of educating beef cattle producers on best practices and management. Reproduction management strategies are essential in ensuring beef cow-calf producers achieve one healthy calf, per cow, every year. Every year, during the VMC, a survey on reproductive management practices and adoption of technologies is performed as a representation of current practices of beef cow-calf producers. Over three years (2021-2023), we obtained data from a total of 276 producers in VA. Out of all participants, 71.74% indicated that they had a defined breeding season. Of those, 33.17% had a breeding season of 70 days or less. Furthermore, 47.81% of producers had both a Fall and Spring breeding season, while 24.12% and 28.07% of participants designated their breeding seasons as either Fall or Spring, respectively. Moreover, 62.28% of participants reported that 40% or more of their cows calve within the first 21 days of the calving season. The bull-to-cow ratio was assessed on operations electing to use natural service, with 71.27% of producers having a minimum of a 1:25 bull-to-cow ratio. A total of 66.54% of the participants reported regularly measuring body condition score of their cows. Over the three years, the most adopted reproductive practice on farms was pregnancy diagnosis, with 31.13% of producers indicating they perform pregnancy diagnosis on their herds every year. The second most utilized practice is the bull breeding soundness exam, with 26.11%. Artificial insemination is continuously gaining popularity, with 19.44% of producers reporting they artificially inseminated their cattle over the past three years. Additionally, 15% of producers reported estrus synchronization of their cattle. However, embryo transfer and sexed semen are the two reproductive practices that were least adopted by producers, with 3.72% and 4.60%, respectively. Overall, compared with the 2017 USDA NAHMS cow-calf report, Virginia producers are more advanced with their reproductive management practices compared with the average cattlemen in the United States.

Population Fluctuations of the Deer Mouse (Peromyscus maniculatus) in Old-Field and Bunchgrass–Sagebrush Habitats: The Role of Agricultural Setting and Optimum Habitat

In semiarid regions, the deer mouse (Peromyscus maniculatus) is a major small mammal species occupying perennial grassland habitats that include old-fields, native bunchgrass–sagebrush, and some agricultural settings. We investigated population changes in deer mouse populations in perennial grasslands, both natural and old-field, from 1982 to 2003 in southern British Columbia, Canada. Hypotheses (H) predicted that P. maniculatus populations will have (H1) multiannual fluctuations in abundance driven by population increases from extended breeding in summer and winter; (H2) relaxed spring reorganization events in some years leading to higher overall recruitment and survival; and (H3) interspecific competition with montane voles that causes deer mice to be lower in density when voles are higher. P. maniculatus populations in old-field and grass–sagebrush sites had clearly defined periods of high “peak” mean numbers (32–52/ha) and other times of low mean numbers (20–22/ha). Based on mean annual peak density in autumn, deer mouse populations exhibited fluctuations of 3–4 years in both habitats, but this pattern was not always present. The greater numbers of P. maniculatus in high than low years was directly related to population increases from extended breeding seasons and an increased number of lactating females, thereby supporting H1. Spring breeding season declines occurred but were similar or less in high than low years of mean abundance and were relaxed in comparison to forest populations of deer mice in other studies. Thus, H2 was supported for recruitment with high numbers of young-of-the-year breeding and total number of juvenile recruits but for survival was equivocal. Total summer survival was consistently higher in high than low population years but juvenile productivity in all years was poor. Mean abundance of P. maniculatus and M. montanus in old-field sites were highly correlated, and hence H3 was not supported. This latter result is the first, to our knowledge, of P. maniculatus coexisting in a similar pattern of population fluctuations with a Microtus species in a mainland grassland habitat. Higher than average precipitation in the year preceding a peak population of deer mice may have enhanced herbaceous vegetation and contributed to population increases in both habitats. We conclude that the old-field habitat associated with this agricultural setting provides optimum habitat for P. maniculatus and facilitates multiannual population fluctuations in this species.

58 Reproductive Performance of Beef Cow-Calf Operations in VA with a Fall or Spring Breeding Season

Abstract Establishing two breeding seasons (Fall and Spring) is a common practice in the southeast USA, including VA. We performed a retrospective analysis of data from 11 years, 22 breeding seasons and 14 locations in VA to compare reproductive performance between Fall and Spring breeding seasons. A total of 30,191 breeding records (24,032 for cows and 6,259 for heifers) from the VA Department of Corrections beef cattle operations were analyzed. Every year, each cow and heifer were enrolled in estrous synchronization protocols and received fixed-time artificial insemination (TAI) and were then exposed to natural service bulls for an approximately 65-day breeding season. Fall breeding occurred from November until January, and Spring breeding from March until May. Body condition score (BCS; 1 to 9, scale) was determined at the initiation of the TAI protocol. Estrus detection before TAI was performed by scoring an estrus detection aid prior to insemination. Pregnancy rate was determined by ultrasonography between days 55-65 post-TAI and 40-50 after the end of the breeding season. Data were analyzed using the SAS GLIMMIX procedure for binary data and MIXED procedure for continuous data. Average BCS was greater (P < 0.001) for Fall cattle than Spring cattle (5.7 ± 0.02 and 5.1 ± 0.02, respectively); however, days postpartum at TAI was similar between Fall and Spring (P = 0.645; 77.8 and 76.2 ± 0.5 days, respectively). Pregnancy rate to TAI differed (P < 0.0001) between Fall and Spring, 53.0 ± 0.03% and 48.6 ± 0.05%, respectively. Interestingly, estrus expression was greater (P < 0.001) for Spring than Fall (58.4 ± 0.05% and 50.4 ± 0.06%, respectively) and also was greater for cows that became pregnant to TAI compared with cows that failed to become pregnant to TAI (P < 0.001; 61.7 ± 0.03% and 46.9 ± 0.04%, respectively). End of breeding season pregnancy rate differed between season and was greater for Fall than Spring (P < 0.001; 90.7 ± 0.04% and 87.9 ± 0.04%, respectively). Calf birth weight was similar between seasons (P = 0.478; 34.1 and 34.4 ± 0.09 kg, for Fall and Spring, respectively). However, 205-day adjusted weaning weights differed (P < 0.001) between seasons with Spring calves being heavier than Fall calves (246.3 ± 0.12 kg and 227.8 ± 0.21 kg, respectively). In conclusion, for beef cow-calf operations in VA reproductive performance is enhanced for Fall breeding seasons; however, weaning weights were greater for calves born during the Spring seasons.

Assessing pregnancy outcomes in cow-calf operations after administration of modified-live or killed virus vaccinations at the initiation of synchronization for fixed-time AI

The objective of this study was to compare the reproductive outcomes (artificial insemination [AI] pregnancy rates, season pregnancy rates, AI pregnancy losses) and calf traits (birth and weaning weights) after vaccination of suckled beef cows against bovine herpesvirus 1 and bovine viral diarrhea virus using commercially-available modified-live virus (MLV) or killed virus (KV) vaccine at the initiation of a fixed-time AI program. Previously-vaccinated cows (n = 2138) on 14 farms throughout Virginia were enrolled in the study during the Fall 2017 and Spring 2018 breeding seasons. Animals received a single vaccination injection at 10 d pre-breeding, corresponding with time of CIDR insertion at initiation of the 7-d CO-Synch + CIDR synchronization protocol. Cows were inseminated at a fixed time (60–66 h after removal of the CIDR insert) and subsequently turned out with bulls approximately 1 wk after insemination for a natural service. Cows treated with the MLV vaccine had greater AI pregnancy rates than cows treated with the KV vaccine during the fall (P = 0.008; 54% vs. 46%, respectively), but not during the spring breeding season (P = 0.62; 48 vs. 49%). Season pregnancy rates were greater (P = 0.01) in the fall (95–96%) than in the spring breeding season (89–90%), but were not affected by vaccine treatment (P = 0.49) or treatment by season (P = 0.30) interactions. Percentage of AI pregnancy losses was not affected by season (P = 0.85), vaccine treatment (P = 0.83), or treatment by season interactions (P = 0.68). The number of cycles it took for cows to become pregnant by natural service differed by season (P = 0.006) but not treatment (P = 0.87) or treatment by season interaction (P = 0.997). Cows treated with the MLV vaccine gave birth earlier in the calving season (8.36 ± 0.6 d) than those treated with the KV vaccine (10.31 ± 0.6 d; P = 0.02). There was a main effect of season on birth weights (P = 0.008), weaning weights (P < 0.001), and ADG at weaning (P < 0.001), but no effects of treatment (P ≥ 0.26) or treatment by season interaction (P ≥ 0.10) on any of these parameters. Overall, this study demonstrated that the administration of an MLV vaccine at 10 d before fixed-time AI did not have any adverse effects on pregnancy or calf outcomes compared with KV vaccine administration.

PSX-B-20 Survey of Reproductive Management Practices for Beef cow-Calf Producers in Virginia

Abstract The Virginia Master Cattlemen program has the goal to provide beef producers with essential knowledge in areas of beef production. Every year, beef producers from VA and neighboring states participate in this comprehensive 14-hour long program. During the 2021 program, we performed an online survey with participants addressing their reproductive management practices. We have obtained data from 133 participants, of which 67.7% indicated their operations have a defined breeding season. Of those, 41.1% have reported the length of the breeding season to be less than 70 days. In addition, 64.6% of participants indicated that at least 40% of their cows will calve during the first 21 days of their calving season. As far as seasonality, 50.9% of participants reported to have both a fall and spring breeding seasons, whereas 24% and 25% of participants reported to only hold their breeding season in the fall, and spring, respectively. Furthermore, only 35% of participants indicated that they collect body condition scores of their herds on a regular basis. In regards to natural service, 84.8% of participants reported to have a bull:cow ratio of 1:25 cows or greater during the breeding season; however only 50% of participants reported performing a breeding soundness exam prior to the breeding season. Finally, pregnancy diagnostics was the most commonly adopted reproductive technology, with 80% of participants indicating to perform pregnancy diagnosis every year, followed by 55% participants adopting artificial insemination, and 45% adoption of estrus synchronization. The least adopted reproductive technologies were embryo transfer with 9%, and sexed semen with only 10% of participants indicating use of those technologies. Contrasting our data with the 2017 USDA NAHMS Cow-Calf Study, participants of the VA Master Cattlemen program have a greater adoption of reproductive technologies than the average cattlemen in the USA.

Eavesdropping on conspecific alarm calls links birds across territory borders into a population-wide information network

Animal communication, including the transmission of risk-related information, has long been recognized as occurring in a network, rather than being limited to signaller–receiver dyadic interactions. However, it is rare for studies on communication to explicitly incorporate a network approach and for network studies to focus on communication interactions and information transmission in nongrouping species. Consequently, the properties of communication networks and the extent to which risk-related information can spread through populations of territorial animals remain largely unexplored. Here, I examined the structure and spatial extent of eavesdropping networks by studying alarm calls in wood warblers, Phylloscopus sibilatrix, small, territorial songbirds inhabiting temperate European forests. Using a playback experiment, I first established the active space of wood warblers' alarm signals, that is, how the strength of antipredator responses to conspecific alarm calls varies as a function of distance between signallers and receivers. Next, I combined social network analysis and fine-scale, long-term data on wood warblers' territory distribution to delineate spatially explicit alarm call eavesdropping networks and to explore the potential for risk-related information transmission at the population level. Response strength of wood warblers to conspecific calls decreased with increasing distance to callers, suggesting distance-dependent eavesdropping. However, each year the majority of individuals occupied territories within the active space of alarm signals of multiple neighbours and could reach information from even more of them via indirect links. Moreover, the patterns of connections between individuals were generally similar across years, suggesting that basic network properties remain stable over time. This study shows that during the spring breeding season, individual birds are interlinked with conspecifics across territory borders into population-wide information webs, in which risk-related information can readily spread across large spatial scales. In turn, this highlights the social environment as an important dimension of individuals’ niches even in otherwise territorial animals.

Divergent physiological acclimation responses to warming between two co-occurring salamander species and implications for terrestrial survival

Small differences in physiological responses are known to influence demographic rates such as survival. We tested for differences in the physiological acclimation responses of two closely-related salamander species that often co-occur, Ambystoma maculatum and A. opacum. Specifically, we measured changes in critical thermal maxima (CTmax), standard metabolic rates (SMRs), and respiratory surface area water loss (RSAWL) following exposure to three temperature treatments under laboratory conditions. While the magnitude of RSAWL and CTmax acclimation responses to warming did not differ between the study species, SMR was maintained across acclimation temperatures among A. maculatum, but declined among A. opacum acclimated to warmer temperatures. Metabolic compensation may facilitate maintained A. maculatum activity levels during warm periods following the relatively cool spring breeding season. In contrast, metabolic suppression may allow A. opacum to conserve energy when exposed to surface conditions during fall breeding and nest guarding. We simulated how these different SMR responses would likely alter post-metamorphic survival in our study species using previously collected data representing six weeks under relatively warm seminatural conditions. Our simulation indicated that, following warming and under identical study conditions, metabolic compensation may allow juvenile A. maculatum to maintain survival likelihoods, whereas metabolic depression may cause juvenile A. opacum to experience increased survivorship. These findings underscore that comparable physiological responses among ecologically similar, sympatric species cannot be assumed. Further, results of this study suggest that metabolic responses may play an important role in amphibian species persistence as temperatures increase due to habitat modification and climate change.

Environmental correlates of activity and energetics in a wide-ranging social carnivore

BackgroundEnvironmental conditions can influence animal movements, determining when and how much animals move. Yet few studies have quantified how abiotic environmental factors (e.g., ambient temperature, snow depth, precipitation) may affect the activity patterns and metabolic demands of wide-ranging large predators. We demonstrate the utility of accelerometers in combination with more traditional GPS telemetry to measure energy expenditure, ranging patterns, and movement ecology of 5 gray wolves (Canis lupus), a wide-ranging social carnivore, from spring through autumn 2015 in interior Alaska, USA.ResultsWolves exhibited substantial variability in home range size (range 500–8300 km2) that was not correlated with daily energy expenditure. Mean daily energy expenditure and travel distance were 22 MJ and 18 km day−1, respectively. Wolves spent 20% and 17% more energy during the summer pup rearing and autumn recruitment seasons than the spring breeding season, respectively, regardless of pack reproductive status. Wolves were predominantly crepuscular but during the night spent 2.4 × more time engaged in high energy activities (such as running) during the pup rearing season than the breeding season.ConclusionIntegrating accelerometry with GPS telemetry can reveal detailed insights into the activity and energetics of wide-ranging predators. Heavy precipitation, deep snow, and high ambient temperatures each reduced wolf mobility, suggesting that abiotic conditions can impact wolf movement decisions. Identifying such patterns is an important step toward evaluating the influence of environmental factors on the space use and energy allocation in carnivores with ecosystem-wide cascading effects, particularly under changing climatic conditions.

Livestock grazing, climatic variation, and breeding phenology jointly shape disease dynamics and survival in a wild amphibian

Wildlife responses to infectious disease can be influenced by environmental stressors that alter host-pathogen dynamics. We investigated how livestock grazing, climatic variation, and breeding phenology influence disease prevalence and annual survival in boreal toad (Anaxyrus boreas boreas) populations challenged with Batrachochytrium dendrobatidis (Bd), a fungal pathogen implicated in global amphibian declines. We conducted a five-year (2015–2019) capture-recapture study of boreal toads (n = 1301) inhabiting pastures grazed by cattle in western Wyoming, USA. We employed structural equation models to determine whether the effects of climatic variation on Bd prevalence were direct or mediated through effects on breeding phenology and multi-state models to explore the interplay of grazing, weather, and Bd infection on adult survival. Higher winter snowpack was linked with shorter spring breeding seasons, which were associated with lower Bd prevalence. Boreal toads infected with Bd suffered increased mortality, but only at relatively cool temperatures. Although cattle grazing created warmer microclimates, likely by reducing vegetation cover, grazing-induced habitat changes did not scale up to influence adult survival. Our results suggest that boreal toads in cooler environments face increased risk of disease-induced mortality, possibly because infected individuals are not able to elevate body temperature to reduce or clear infection. More generally, we demonstrate that host-pathogen dynamics can be shaped jointly by independent and interactive effects of livestock grazing, breeding season length, and climatic variation. Future investigations of wildlife responses to disease therefore may benefit from considering anthropogenic land use and climatic regimes, including the effect of weather on host phenology.

Diversity, Distribution and Habitat Use of Freshwater Crayfish in the Upper Appomattox River Basin, Virginia

The Appomattox River basin in Virginia is a poorly understood system for freshwater crayfish diversity and distribution. We sampled 36 locations in the upper Appomattox basin for crayfish and noted general habitat characteristics. The following 7 species of crayfish were discovered in the system belonging to 4 genera: Cambarus cf. acuminatus, Cambarus bartonii bartonii (Common Crayfish), Cambarus longulus (Atlantic Slope Crayfish), Lacunicambarus diogenes (Devil Crayfish), Procambarus acutus (White River Crayfish), Creaserinus fodiens (Digger Crayfish), and invasive Procambarus clarkii (Red Swamp Crayfish). Native C.cf. acuminatus dominates the upper Appomattox region, having a wider distribution and higher relative abundance compared to other species in the basin. All other taxa demonstrated relatively limited distributions and low abundance. The least encountered species were the 2 primary burrowing species, Devil Crayfish and Digger Crayfish, which exclusively used shallow seasonal pools during the spring breeding season. We report range extensions for C. cf. acuminatus, Atlantic Slope Crayfish, Common Crayfish, Devil Crayfish, Digger Crayfish, and Red Swamp Crayfish, and recommend additional surveys to improve our understanding of the diversity and distribution of crayfish in the Appomattox River basin. Furthermore, we recommend monitoring of the Briery Creek and Sandy River systems to assess the extent and severity of the Red Swamp Crayfish invasion. Additionally, we urge a systematic study to resolve the taxonomic uncertainty of a potentially new Creaserinus species in the Appomattox River basin.

Diet and Feeding Frequency in the Southwestern Speckled Rattlesnake (Crotalus pyrrhus): Ontogenetic, Sexual, Geographic, and Seasonal Variation

Dietary studies are central to our understanding of organismal biology. We describe the diet and frequency of feeding in the Southwestern Speckled Rattlesnake (Crotalus pyrrhus). We used data from wild-caught specimens collected from six biogeographic regions (pooled to three regions for analysis) across the species' range in the United States that include Arizona, California, and Nevada, USA. Fecal material from 185 snakes yielded 104 prey items from 72 individuals, and palpation indicated recent meal ingestion in 36 of 174 individuals. The diet consisted predominantly of mammals (80.8%), in particular terrestrial squirrels (39.4%) and members of the heteromyid rodent genus Chaetodipus (26.9%). Male and female snakes exhibited similar diets and feeding frequency, but an ontogenetic shift occurred from primarily ectothermic (lizards) to endothermic prey (rodents and birds) and more frequent feeding. Consumption of ectotherms vs. endotherms appeared to be similar among biogeographic regions, but snakes from the Tinajas Altas Mountains, Arizona, preyed disproportionately on birds compared with other regions, and snakes from the Sonoran Desert-Arizona Upland region more frequently ingested recent meals than those from the California-Nevada region. Regardless of sex, size, and biogeographic region, snakes consumed fewer prey during the spring breeding season than during summer and autumn. We provide data on the diet of C. pyrrhus for testing further hypotheses regarding potential interspecific competition, dietary changes associated with climate change, foraging tactics associated with bird predation, competing behaviors during breeding season, and venom composition variation.

Songbird use of interior and edge floodplain forest sites along the Upper Mississippi River, USA, during spring migration and breeding seasons

Floodplain forests of large rivers in the midwestern United States are naturally fragmented by sloughs, backwaters, wetlands, and shrub carr. On the highly altered Upper Mississippi River (UMR), resource managers want to protect and manage floodplain forests to benefit forest “interior” bird species. To discover bird relations with interior and edge floodplain forest, we characterized bird assemblages during spring migration and breeding season in 3 forest types: habitat in the interior of forest areas > 100 m from an edge, edges associated with interior areas, and other areas of forest not associated with an interior area (random sites) on the UMR between Hastings and Red Wing, Minnesota. The random sites represent the majority of UMR floodplain forest area because only a small percentage of forest occurs >100 m from edge. Estimated habitat characteristics did not differ among interior, edge, and random sites. Bird relative abundance, species richness, diversity, assemblage composition, and detections of all but one species (in spring) did not differ among interior, edge, and random sites during both seasons. Our results suggest a homogeneous bird assemblage across UMR floodplain forest in the study area during spring migration and the breeding season, and that individual forest bird species do not seem to be more abundant in interior or edge areas as we defined them.

Antarctic pack ice seal observations during spring across the Lazarev Sea

Abstract The distribution, density and percentage contribution of pack ice seals during ship-board censuses in the marginal sea ice zone beyond the Lazarev Sea in spring 2019 are presented. Adult/juvenile crabeater seals (n = 19), leopard seals (n = 3) and Ross seals (n = 10) were sighted during 582.2 nm of censuses along the ship’s track line in the area bounded by 00°00’–22°E and 56°–60°S. Antarctic fur seals (n = 21) were only encountered on the outer fringes of the pack ice, and Weddell seals were absent due to their primary use of fast ice and inner pack ice habitats close to the coast. Crabeater seal sightings included juveniles (n = 2) and another four groups of 2–3 unclassified crabeater seals, singletons (n = 5), single mothers with pups (n = 3) and a family group (n = 1 triad). Only one leopard seal attended a pup, while no Ross seal pups were located. The survey was likely of insufficient effort, in both extent (north of 60°S) and duration (18 days), to locate seals in considerable numbers this early (late October/early November) in their austral spring breeding season.

Assessing ecological and environmental influences on boreal chorus frog (Pseudacris maculata) spring calling phenology using multimodal passive monitoring technologies

Although anuran reproductive behavior follows a phenological pattern, environmental factors may influence the timing of anuran activity. To characterize the spring calling phenology of Pseudacris maculata (boreal chorus frog) we installed acoustic recorders during three spring breeding seasons (2015–2017) within wet meadow and forested slough habitats in central Nebraska near the Platte River. The recorders were paired with time-lapse camera systems that were used to measure vegetation change and wet meadow inundation. We examined the relationship between environmental variables, including temperature, precipitation, and hydropattern, and P. maculata calling activity using random forest models. Calling activity exhibited diel and seasonal variation with differences observed between habitats. Hourly call activity was highest between 20:00 and 01:00, with diurnal and sometimes near-continuous calling observed at the wet meadow but not at the forested slough. Random forest models explained 73% of calling activity variance at the wet meadow and 45% at the forested slough, suggesting additional factors, such as predation, may be influential at the forested slough, as it exhibited near permanent hydrology. P. maculata was predicted to increase chorusing at the 70th day of the year at the wet meadow but not until the 100th at the forested slough. When average air temperatures exceeded 5 °C, calling activity was predicted to increase at both wetlands, and calling declined below this temperature. Hydropattern and weekly precipitation accumulation were important predictors of P. maculata calling activity. Our findings highlight the importance of climatic factors such as temperature and precipitation regimes, in addition to habitat conditions such as water-availability, on P. maculata calling activity. Furthermore, this study demonstrates the utility of multimodal passive monitoring technologies, including both visual and auditory tools, for understanding the environmental factors that influence biological activity. Multimodal approaches can be especially useful for documenting and measuring vocal-taxa diversity, activity, and drivers of change.

Long-term consistency despite cross-seasonal changes in personality traits of common waxbills

Abstract Tests of long-term consistency in personality differences are not abundant. We studied personality in common waxbills (Estrilda astrild) from one Autumn to the next, and also from Autumn to a subsequent Spring, using a behavioural assay for their proactive-reactive personality axis (mirror test) and for tonic immobility. From one Autumn to the next, individual differences were consistent and the population median behaviours did not change, indicating long-term stability of personality differences. From Autumn to Spring, behavioural differences remained consistent, despite the population shifting to more proactive behaviour and individual differences being accentuated in the proactive-reactive personality axis. This increase in personality differences was not found between the two previous Autumns, suggesting a seasonal rather than longitudinal change, and a possible role for personality differences during the Spring breeding season. We conclude that waxbill personality differences are stable in the long term, despite changes in behaviour between Autumn and Spring.

The Healthy and Diseased Equine Endometrium: A Review of Morphological Features and Molecular Analyses.

Simple SummaryDiseases of the endometrium are a frequent cause of subfertility in mares and have an economic impact on the horse breeding industry. These include periglandular fibrosis of endometrial glands (endometrosis), degenerative diseases of vessels (angiosis), inflammation (endometritis), as well as altered differentiation of endometrial glands. Some mares are susceptible towards persistent endometritis. The etiology and pathogenesis of endometrosis are still unclear. This review describes morphological hallmarks and molecular features associated with endometrial health and different types of diseases. The presented literature data reveal characteristic differences in the expression of several extra- and intracellular molecules between the healthy and diseased equine endometrium. Some of these molecules can be detected directly within the tissue and thus have the potential to serve as excellent diagnostic markers for the presence of endometrial diseases. The knowledge of disease-associated changes in cellular differentiation, secretory functions, and immune mechanisms will help to decipher pathogenesis and will contribute to the development of novel treatments. In addition, the quantification of molecular alterations may contribute to a fertility prognosis for an individual mare. Reproductive health increases the well-being of mares and reduces financial loss for the horse breeding industry.Mares are seasonally polyestric. The breeding season in spring and summer and the winter anestrus are flanked by transitional periods. Endometrial diseases are a frequent cause of subfertility and have an economic impact on the horse breeding industry. They include different forms of endometrosis, endometritis, glandular maldifferentiation, and angiosis. Except for suppurative endometritis, these are subclinical and can only be diagnosed by the microscopic examination of an endometrial biopsy. Endometrosis is characterized by periglandular fibrosis and nonsuppurative endometritis by stromal infiltration with lymphocytes and plasma cells. The pathogenesis of endometrosis and nonsuppurative endometritis is still undetermined. Some mares are predisposed to persistent endometritis; this has likely a multifactorial etiology. Glandular differentiation has to be interpreted under consideration of the season. The presence of endometrial diseases is associated with alterations in the expression of several intra- and extracellular molecular markers. Some of them may have potential to be used as diagnostic biomarkers for equine endometrial health and disease. The aim of this review is to provide an overview on pathomorphological findings of equine endometrial diseases, to outline data on analyses of cellular and molecular mechanisms, and to discuss the impact of these data on reproduction and treatment.

The function of food storing in shrikes: the importance of larders for the condition of females and during inclement weather

Food storing is a well-known phenomenon among birds, described in shrikes Laniidae. The preferred explanation suggests that its function is to signify male quality to females and to mark territorial borders during the mating period. The importance of food storing must vary among different species, however, because in the Red-backed Shrike Lanius collurio, this behaviour takes place during the nestling care period. The aim of this study was to evaluate the significance of food storing by male Red-backed Shrikes. We did not find any differences in the breeding parameters between pairs in which the males did or did not store food. There was, however, a significant tendency for the number of stored prey items to increase when the atmospheric pressure was falling prior to the onset of rain. The mates of males that did store food had a larger body mass than those females whose partners did not do so. This study showed that food storage have a variety of functions, including different ones compared with those described for the best-known shrike species. Differences in food storing phenology in various shrike species are probably due to the period when they start nesting: Red-backed Shrikes start their breeding season in late spring, when food is plentiful. Our study demonstrates that the abundance of food in territories and one’s own condition, as expressed by the number of prey items stored when food is readily available, is not really so relevant. The food store of a Red-backed Shrike thus functions as a larder, which the female makes use of when her energy requirements are the highest, i.e. when caring for her young. Larders are thus essential if females are to remain in good bodily condition: this could be significant if a clutch is lost and a replacement one has to be laid.