Hawk Mountain Sanctuary

The purpose of this study was to ascertain how long raw chicken meat and beef meat kept at 4°C in a typical home refrigerator would last. Researchers from Chattogram Veterinary and Animal Sciences University performed an extensive examination over five days, assessing 10 meat samples (five chicken meat and five beef meat) obtained from local markets in Chattogram (Jhawtola, Bahaddar Hat, and Chawk Bazar). The quality assessment encompassed physico-chemical, microbiological, and sensory criteria, including pH, water holding capacity (WHC), extract release volume (ERV), protein degradation (tyrosine value), fat oxidation (TBARS), total viable microbial count (TVC), and aroma. Significant data indicated a gradual deterioration in quality for both types of meat. Sensory evaluation indicated a significant escalation in offodours, becoming especially evident by the fifth day. Physicochemical research revealed a steady decrease in pH for chicken, whereas beef pH exhibited greater variability. The water-holding capacity was minimal for both meats on the penultimate day. Moreover, elevated tyrosine and TBARS levels indicated continuous breakdown of proteins and lipids, respectively. Microbiologically, beef had a greater overall viable count compared to chicken. The study revealed that whereas beef demonstrated a more rapid decomposition rate, both meats underwent considerable quality degradation by the fifth day of refrigerated storage. These findings point out the importance of appropriate raw meat handling and timely storage techniques for preserving domestic food safety and quality.

Abstract Every year, millions of raptors migrate between their breeding areas in North America and their nonbreeding areas in Central and South America. Many investigations have demonstrated that weather plays a significant, yet complex role in the timing of bird migration at northern localities that, in turn, shapes their seasonal migration phenology. However, very little information is available for the Neotropical region. Here, we analyzed the relationship between local weather variables (wind-related components, humidity, and atmospheric pressure) and the intra- and inter-annual migration patterns of 8 raptor species with different migration ecologies. Our dataset spans between 23–26 years and was obtained at a raptor migration monitoring site at Mexico’s Gulf coastal plain, a well-known, globally important migration hotspot. Perhaps due to the often erratic and pulsed daily variation in migration phenology each year, classical analytical approaches do not consider quantifications of intra-annual variation. To address this, we devised a new method based on a finite approximation to the second derivative of the counts (roughness) to analyze the role of weather drivers in the patterns of daily counts. Additionally, we analyzed the inter-annual variation in migration timing, subtracting the mean number of individuals across all years for each day (deviations from the mean). Although we found significant differences in roughness across days, we observed a subtle association between weather and roughness in migration counts, regardless of the species’ flight strategy (such as thermal soaring and flapping). Only tailwind affected the intra-annual migration, although the models had a low explanatory power (marginal R2 ≤ 0.17). Similarly, we found inter-annual effects of tailwind and sidewind, depending on the type of migrant (long- and short-distance), but the models exhibited high variation and low explanatory power (marginal R2 ≤ 0.18). Moreover, the lagged effect of weather variables does not improve the variance explained by weather variables at any of the two timescales evaluated. The low association between migrant counts and weather calls for future research at larger spatial and temporal scales, as well as on assessing the cumulative effect of weather along raptor migration routes.

ABSTRACTAimTo understand the influence of Andean uplifts and glacial cycles on South American biodiversity, we delve into the population genetics and evolutionary history of a unique subantarctic island raptor specialised in exploiting marine food webs.LocationIslands in Tierra del Fuego and Malvinas/Falklands.Time periodLast glacial period to the present.Taxon Phalcoboenus australis. MethodsWe used RAD sequencing to assess genetic diversity, population structure and to model demographic history through descriptive and hypothesis‐based evolutionary methods.ResultsWe found evidence of two independent lineages: one inhabiting the Fuegian archipelago and the other one occurring in the Islas Malvinas/Falkland Islands, with the latter presenting higher genetic diversity and evidence of finer‐scale population structure. The best supported demographic scenario places the divergence time of these lineages during the last glacial period (ca. 50,000 years ago), with the occurrence of gene flow during the first 27,000 years after their divergence. Recent demographic modelling supports the general pattern of increasing genetic variability as landmasses were uncovered following the glacial period (i.e., the Fuegian archipelago) in contrast with a decrease in genetic diversity associated to island fragmentation (i.e., in the Islas Malvinas/Falkland Islands).Main ConclusionsWe propose that post‐glacial sea level rise and the subsequent isolation across the submerging Patagonian Shelf have driven population fragmentation and recent genetic structure in this species. Our findings advocate for recognising the two identified divergent lineages as distinct conservation units. We highlight the intricate interplay of ecological factors, glacial cycles and population dynamics in shaping the evolutionary trajectory of this unique and threatened raptor species in southern South America.

Recent studies highlighted the presence of anti-α-Gal antibodies in patients implanted with commercial bioprosthetic heart valves (BHVs). BHVs expose residual α-Gal xenoantigen and their recognition by the circulating anti-Gal antibodies leads to opsonization of the device's tissue component with the consequent triggering of a deterioration pathway that culminates with calcification. Small animal models such as mice and rats have been broadly involved in the in vivo testing of biomaterials by subcutaneous implantation, especially for the effectiveness of BHVs anti-calcific treatments. However, since models employed for this purpose express α-Gal antigen, the implantation of BHVs' leaflets does not elicit a proper immunological response, so the calcification propensity may be dramatically underestimated. An α-Gal knockout (KO) mouse model has been created, using the CRISP/Cas9 approach, and adopted to assess the calcification potential of commercial BHVs leaflets through the surgical implantation in the back subcutis area. Calcium quantification was performed by inductively coupled plasma analysis; immune response against the BHVs leaflets and α-Gal silencing was evaluated through immunological assays. Two months after the implantation of commercial BHV leaflets, the anti-Gal antibody titers in KO mice doubled when compared with those found in wild-type (WT) ones. Leaflets explanted from KO mice, after one month, showed a four-time increased calcium deposition concerning the ones explanted from WT. The degree of silencing of α-Gal varied, depending on the specific organ that was assessed. In any case, the animal model was suitable for evaluating implanted tissue responses. Such mouse model proved to be an accurate tool for the study of the calcific propensity of commercial BHVs leaflets than those hitherto used. Given its reliability, it could also be successfully used to study even other diseases in which the possible involvement of α-Gal has been observed.

Abstract Reproduction of long-distance migrants can be affected by local conditions on the breeding grounds as well as those encountered during the nonbreeding season through carry-over effects. We show that this is true in Long-tailed Jaegers (Stercorarius longicaudus) because individuals that spent less time flying at sea during winter had a high breeding propensity and a reduced pre-laying interval, but breeding propensity and nesting success were also positively associated with food abundance at the breeding site. This seabird switches from a marine to a terrestrial lifestyle to breed in summer in the Arctic, where it primarily feeds on lemmings. We monitored jaeger reproduction and lemming densities on Bylot Island in the Canadian Arctic for 16 years, and we used geolocator to study annual movements. We assessed whether movement parameters (travel distance, migration duration, phenology, and number of flying bouts inferred by saltwater immersions) during the nonbreeding season affected the breeding propensity, phenology, and success of individuals. We also examined whether cyclic lemming fluctuations influenced Long-tailed Jaeger reproduction and whether nesting success affected the phenology of their outbound migration. We found that increased time spent flying during winter and early arrival at the breeding site reduced breeding propensity. Moreover, spending less time flying during winter shortened the pre-laying period, and advancing laying date increased nesting success. Birds may thus face a trade-off to minimize the relative costs associated with arriving too early and breeding too late. Local food availability had a strong effect on reproduction because breeding propensity and nesting success increased sharply with lemming abundance. Failed breeders advanced their outbound migration by 10 days on average compared to successful ones, but migration duration was similar. Therefore, the unpredictability of the highly seasonal Arctic environment, especially fluctuating food abundance, appears to be a strong driver of reproduction that can modulate the strength of carry-over effects.

The Black-and-chestnut Eagle Spizaetus isidori is an endangered and little-known top predator of South American montane forests. To better understand the breeding ecology and threats of this eagle, we studied several pairs between 2017 and 2022 in the central Andes of Peru. We recorded 62 adults, one immature, and 36 juveniles in 36 territories. These territories were in mountainous areas (altitudinal range 690–3,810 m a.s.l.), widely covered by montane forests (43.8–99.7% cover), and secondarily by open land (0.3–56.2% cover), far from urban settlements (1.3–27.1 km). Nesting sites (N = 15) were at medium altitudes (1,330–2,330 m a.s.l.) in steep hillsides or ravines (15–55°), having no preferential cardinal orientation, and relatively close to permanent water courses (20–800 m), open areas (30–930 m) and sites with human activity (120–2,200 m). Nests (N = 15) were placed at the top of tall (28–40 m) and thick-stemmed (DBH range 0.53–1.52 m) emergent trees of nine genera, with Ficus and Juglans being the most used. Incubation and brood-rearing occurred during the dry season (Mar–Nov). The wooded slopes where the eagles nested are being replaced by crops and livestock pastures, causing an estimated loss of 218.2 km2 of forest cover in our study area (5,056 km2) during the last 20 years. We detected human persecution in 55.5% of the territories, resulting in 26 juveniles, four adults, two immatures, and nine unaged eagles killed. Preventing the local extinctions of these eagles will require long-term population monitoring, improving knowledge of its ecology, mitigation of human-eagle conflict, development of education programs, and strengthening of land use inspection.

Abstract The demography of, and factors that influence these metrics, are largely unknown for most vultures in the Americas. Survivorship of Turkey Vultures (Cathartes aura) may be influenced by landscape heterogeneity and human disturbance. We quantified the effects of landscape composition (Shannon’s diversity index) and configuration (contagion, edge density, and largest patch index), and human disturbance (road density) on the annual and seasonal survival probabilities of the three North American breeding populations (western, central, and eastern) of Turkey Vultures that spend the nonbreeding season in the southeastern portion of the Nearctic and the northern Neotropics during a 17-year period. We used Cox’s proportional hazards models with time-varying covariates to estimate spatial and temporal changes in survival rates of adult Turkey Vultures. Road density, but not landscape composition or configuration, influenced survival rates in space and time. Overall annual survival averaged 0.87 (95% confidence interval [CI]: 0.74–0.98). Mortality risk was low in western and central populations (hazard ratio < 1) but was 3.7 times greater for vultures in the eastern population. Survival during the breeding (0.97, 95% CI: 0.96–0.98) and outbound migration (1.0, 95% CI: 1–1) seasons was significantly higher than the other seasons. Average survival tended to be higher for nonbreeding (0.81, 95% CI: 0.71–0.88) compared to return migration (0.69, 95% CI: 0.56–0.81) seasons. The risk of mortality for all vulture populations increased with road density, and this was greater during the nonbreeding and return migration seasons. The spatial variation in road density across the Americas may generate a network of ecological traps for Turkey Vultures induced to stop in areas of greater road-kill abundance. Road-killed animals acting as an attractant for vultures can increase the occurrence of vulture–vehicle collisions and potentially aggravate human–wildlife conflicts. Further analyses are needed to address survivorship and mortality factors for young birds. Our results may help the implementation of specific mitigation efforts to reduce human–vulture conflicts and vulture mortality. For instance, concentrating efforts to remove road-killed animals in areas where road density is highest can likely reduce vulture–vehicle collisions and associated mortalities of these birds.

Abstract Feet and talons are the most specialized predatory attributes of raptor morphology. As such, the hindlimb morphology of owls should reflect their dietary specialization. Owls' diet varies widely between species with only a subset of owl species preying predominantly on small mammals. We hypothesize that different owl species have varied hindlimb morphology, adapted to their main prey types, and that only dietary specialists will be distinguishable based on talon morphology (e.g. toe length, talon curvature and thickness, etc.). We used a sample of 63 specimens from 15 owl species to obtain a variety of measurements of hindlimb morphology. We then used a discriminant function analysis to investigate the degree of variation between species and diet groups in terms of their morphological measurements. Our results indicate that talon morphology is linked to prey type in the owl species studied. Insect specialists and small mammal specialists were characterized by a low talon curvature, whereas generalists presented a pronounced talon curvature. Fish specialists presented particularly thick and robust talons, and insect specialists showed lower digit strength than other owl species. These findings could help determine the diet of other owl species, particularly endangered species for which data on diet is often scarce. This study will also be very useful in future studies of the ecology of sympatric species, resource partitioning between species, or between sexes of the same species, and more generally to the evolution of owls.