Effects of Weather On Foraging Success and Hunting Frequency In Winter-Irruptive Snowy Owls (Bubo scandiacus) In Upstate New York

ABSTRACT The effects of weather on an individual can often alter the population dynamics of a species. Knowledge of how weather influences individual behavior is therefore essential in understanding its full impact in the context of population ecology. Snowy Owls (Bubo scandiacus) exhibit expensive long-distance migrations in winters following population irruptions. During irruptive movements, many owls migrate past the southernmost extent of their traditional wintering grounds, the mechanism for which is still debated. We propose and test the “milder climate” hypothesis; Snowy Owls wintering in lower latitudes are better able to meet their metabolic demands due to higher temperatures and lower snow cover. During the Snowy Owl irruption of 2014–2015, we examined this hypothesis by assessing the influence of local weather variables on foraging success, frequency of prey capture attempts, and overall activity budgets in a sample of wintering Snowy Owls in New York, USA. We used eBird, an online citizen science resource, to help locate Snowy Owls, which we observed from an automobile. We found that none of the weather variables tested affected foraging success. However, the lack of effect of snow depth on foraging success may suggest that hearing is more important for hunting in Snowy Owls than previously thought. Hunting frequency decreased with increasing temperatures, suggesting Snowy Owls were better able to meet their metabolic demands in higher temperatures. We thus offer support for the milder climate hypothesis; Snowy Owls wintering in lower latitudes may be able to offset the energetic expenses of long-distance movements.

Hunting of mammals by central chimpanzees (Pan troglodytes troglodytes) in the Loango National Park, Gabon

The predation and consumption of animals are common behaviours in chimpanzees across tropical Africa. To date, however, relatively little is known concerning the hunting behaviour of central chimpanzees (Pan troglodytes troglodytes). Here, we provide the first direct observations of hunting behaviour by individuals of the newly habituated Rekambo community in the Loango National Park, Gabon. Over a period of 23 months (May 2017 to March 2019), we observed a total of 61 predation attempts on eight mammal species, including four monkey species. The two most frequently hunted species were two monkey species (Cercocebus torquatus,Cercopithecus nictitans), which are not hunted at other long-term field sites. The majority of predation events observed involved parties of an average of eight individuals, mainly adult males, with hunting success being higher with increasing numbers of participants. Hunting occurred all year round, but hunting rates increased in the dry season, the period of high fruit availability in the Loango National Park. These results are in line with the nutrient surplus hypothesis which explains seasonal variation in hunting behaviour in several populations of eastern chimpanzees (Pan troglodytes schweinfurthii: e.g., Mahale, Tanzania; Ngogo, Uganda). Finally, with a hunting frequency of 2.65 hunts per month, the Rekambo community had higher hunting rates than other sites (Bossou, Republic of Guinea; Kahuzi-Biega, Democratic Republic of Congo; Budongo, Uganda) where red colobus monkeys are also absent. We discuss these results and compare them to patterns at other long-term sites.

Subsistence Hunting During the COVID-19 Pandemic: The Case of the White-Tailed Deer (Odocoileus virginianus) in Rural Communities of Calakmul, Campeche, Mexico

Subsistence hunting for obtaining wild meat is a common practice in rural neotropical communities. Like other peasant practices disrupted by the COVID-19 pandemic, subsistence hunting could exacerbate pressure on wild mammals whose greater size contributes to feeding the hunter and his family. Thus, in the context of the pandemic, we assessed the subsistence hunting of the white-tailed deer ( Odocoileus virginianus), one of the main traditional game species in the Calakmul region, Campeche, Mexico, and compared this activity with its pre-pandemic levels of such vertebrate species. Based on ethnographic information and hunting records from three rural communities, we found that in one trimester (July-September 2020) of the rainy season, a total of 26 white-tailed deer (923 kg of game biomass) were obtained by local peasant-hunters carrying out hunting mostly alone. Most peasant-hunters interviewed (36 of 51) stated that they hunted daily, and only a few hunted once a week or once a month (8 and 3%, respectively). This hunting activity and modalities were carried out at night (68%) versus day, stalking (21%) and opportunist (11%) near their community. The game biomass and hunting frequency in the studied communities were twice as high during the pandemic, compared to similar pre-pandemic periods in the region. Our survey highlights the need to expand monitoring and evaluation (during and after the pandemic) of subsistence hunting on key species, such as white-tailed deer, in order to ensure conservation and sustainable use of wildlife in this important Mesoamerican region.

Research on Low-Frequency Swaying Mechanism of Metro Vehicles Based on Wheel-Rail Relationship

For the worn state of the wheel, metro vehicles often suffer a serious carbody swaying issue, which causes the lateral stability of the vehicle to exceed the limit and affects the ride comfort. An experimental test was carried out on this investigation to study the carbody swaying of the metro vehicle. The field results show that the vehicle system vibrates at around 2.5 Hz in the lateral direction, which leads to the low-frequency swaying on the carbody. In order to explore the formation mechanism of the carbody low-frequency swaying and its relationship with the geometry matching of wheel-rail contact, measured rail and wheel profiles are employed to present a comparative analysis with respect to the initial contact geometry. A multibody dynamic railway vehicle system is established further. Time-domain simulations state that the 2.5 Hz vibration on the carbody belongs to the natural frequency of the vehicle, and the amplitude is larger for the measured wheels than that of the standard wheel profiles. By using the root-locus method, it can be determined that the 2.5 Hz vibration corresponds to the upper swaying mode of the carbody. With the increase in the wheel-rail equivalent conicity, the hunting frequency of bogie increases gradually, which converts frequency with the upper swaying frequency of carbody and leads to carbody low-frequency swaying.

Potensi dan Pemanfaatan Satwa liar di kampung Pasir Putih kabupaten Fakfak Papua Barat

Abstrak: Indonesia merupakan negara megabiodiversiti terutama jenis mamalia, reptilian dan avifauna. Penelitian ini bertujuan untuk mengetahui intensitas pemanfaatan satwa liar di kampung Pasir Putih, Distrik Fakfak Tengah, Kabupaten Fakfak. Dalam penelitian ini objek pengamatan adalah potensi dan pemanfaatan satwa liar di kampung Pasir Putih Kabupaten Fakfak. Variabel pengamatan yang digunakan meliputi informasi dasar tentang jenis satwa liar, status satwa liar berdasarkan IUCN, tujuan pemanfaatan, cara berburu, frekuensi berburu, tingkat keberhasilan berburu, dan jumlah anggota berburu. Data yang diperoleh dianalisis secara tabulasi dan deskriptif untuk memperoleh gambaran objektif kondisi satwa liar yang ada di kampung Pasir putih Kabupaten Fakfak, provinsi Papua Barat. Hasil penelitian diketahui bahwa penduduk di kampung Pasir putih, masih melakukan aktivitas berburu walaupun tidak intens. Beberapa hewan yang dimanfaatkan meliputi hewan avifauna, mamalia dan reptil (herpet). Beberapa hewan masuk dalam kategori terancam punah (VU) oleh Redlist IUCN. Perburuan relatif sulit menggunakan jerat dan anjing berburu, frekuensinya relatif masih rendah dan dengan itu tidak dilakukan secara kolegial karena tingkat kesulitan.Kata kunci: perburuan; satwa liar; pemanfaatan satwa liar; redlist IUCN; Fakfak.Abstract: Indonesia is a mega biodiversity country especially mammals, reptils and avifauna. This study aims to determine the intensity of wildlife utilization in the village of Pasir Putih, Central Fakfak District, Fakfak Regency. In this study the object of observation is the potential and utilization of wildlife in the Pasir Putih village of Fakfak Regency. Observation variables used included basic information about wildlife species, wildlife status based on IUCN, purpose of use, hunting methods, hunting frequency, hunting success rate, and number of hunting members. The data obtained were tabulated and descriptive analyzed to obtain an objective picture of the condition of wild animals in the Pasir Putih village of Fakfak Regency, West Papua province. The results of the study revealed that residents in the white sand village, still doing hunting activities although not intense. Some of the animals used include Avifauna, mammals and reptiles (herpet). Some animals are in the endangered category (VU) by the IUCN Redlist. Hunting is relatively difficult using snares and hunting dogs, its frequency is still relatively low and hence it is not done collegially because of the difficulty level. Keywords: hunting; wild animal; utilization of wild animals; IUCN redlist; Fakfak.

Drivers of hunting in the savannahs of Amapá: implications for conservation

Although overhunting is amongst the main threats to biodiversity, wild meat is culturally and nutritionally important for many communities. Conservation initiatives should therefore address the drivers of hunting, rather than its practice alone. Here we gathered information from structured interviews with 68 local households to assess the drivers of hunting in a highly threatened Amazonian savannah complex, the Cerrado of Amapá in Brazil. We used regression models to evaluate the influence of socio-economic parameters and spatial variables on hunting prevalence and frequency. The only identified driver of hunting prevalence was forest cover, whereas five variables had significant effects on hunting frequency. The positive effect of forest cover and the negative effect of hunter's age on hunting frequency suggest that logistical and physical feasibility are important drivers of hunting frequency. Furthermore, we suggest that the negative effect of distance to urban centres may be related to the profitability of hunting. We base this on the negative effect of river length in the vicinity of households and per capita monthly income on hunting frequency, which corroborates the tendency of hunting frequency to decrease when alternatives to wild meat are more readily available. We argue that to reduce unsustainable hunting it is necessary both to raise awareness amongst local communities and involve them in the creation of management plans that conserve biodiversity and meet economic and social needs.

Numerical Investigation into the Critical Speed and Frequency of the Hunting Motion in Railway Vehicle System

The critical speed and hunting frequency are two basic research objects of vehicle system dynamics and have a significant influence on the dynamic performance. A lateral dynamic model with 17 degrees of freedom was established in this study to investigate the critical speed and hunting frequency of a high-speed railway vehicle. The nonlinearities of wheel/rail contact geometry, creep forces, and yaw damper were all considered. A heuristic nonlinear creep model was employed to estimate the contact force between the wheel and the rail. The Maxwell model, which covers the influence of the stiffness characteristic, is used to simulate the yaw damper. To reflect the blow-off of the yaw damper, the damping coefficient is described by stages. Based on the mathematical model, the combined effects of vehicle parameters on the critical speed in the straight line and hunting frequency of the wheelset were investigated innovatively. The novel phenomenon that the hunting frequency exhibits a sudden increase from a smaller value to a larger value when the blow-off of the yaw damper occurs was discovered during the calculations. The extents to which various parameters affect the critical speed and hunting frequency are clear on the basis of the numerical results. Moreover, all of the parameter values were divided into three sections to determine the sensitive range for the critical speed and hunting frequency. The results show that the first section of values plays the decisive role on both the critical speed and the hunting frequency for all parameters analyzed. The investigation in this paper enriches the study of hunting stability and gives some ideas to probably solve the abnormal vibrations during the actual operation.

Dynamic Investigation of the Hunting Motion of a Railway Bogie in a Curved Track via Bifurcation Analysis

The main purpose of this paper is to analyze and compare the Hopf bifurcation behavior of a two-axle railway bogie and a dual wheelset in the presence of nonlinearities, which are yaw damping forces in the longitudinal suspension system and heuristic creep model of the wheel-rail contact including dead-zone clearance, while running on a curved track. Two-axle railway bogie and dual wheelset were modeled using 12-DOF and 8-DOF system with considering lateral, vertical, roll, and yaw motions. By utilizing Lyapunov’s indirect method, the critical hunting speeds related to these models are evaluated as track radius changes. Hunting defined as the lateral vibration of the wheelset with a large domain was characterized by a limit cycle-type oscillation behavior. Influence of the curved track radius on the lateral displacement of the leading wheelset was also investigated through 2D bifurcation diagram, which is employed in the design of a stable model. Frequency power spectra at critical speeds, which are related to the subcritical and supercritical bifurcations, were represented by comparing the two-axle bogie and dual wheelset model. The evaluated accuracy to predict the critical hunting speed is higher and the hunting frequency in unstable region is lower compared to the dual wheelset model.

Blood Glucose Levels on Beagle (Canis familiaris) in Kenagarian Mungo, Luak District Lima Puluh Kota West Sumatra

This research aimed to determine glucose levels of beagle which is maintained by Sports Association of Pig Hunting (PORBI) in Kenagarian Mungo Sub-district Luak District Lima Puluh Kota, West Sumatra. Blood samples were collected from 20 beagles. Blood sampling was performed during fasting time and two hours postprandial. Data were analyzed with analysis of Chisquare (x2). The results showed that mean glucose level in the fasting state beagle was 63.45±11.84 mg /dl and two hours postprandial was 93.45±12.52 mg/dl. The test results showed statistically significant differences (P<0.05) postprandial, hunting frequency and multivitamin injection on blood glucose levels. The test results showed no statistically significant difference (P>0.05) between the frequency of feeding and supplementary feeding on blood glucose levels. Conclusion average blood glucose levels beagle still in the normal range. There is a difference in blood glucose between two hours postprandial with a fasting blood glucose levels and the difference between the hunting frequency and giving multivitamins injection on blood glucose levels and there was no difference on blood glucose levels between the frequency feeding, and supplemental feeding.Key words: beagle, glucose levels, hunting, multivitamins

KADAR GLUKOSA DARAH ANJING PEMBURU (Canis familiaris) DI KENAGARIAN MUNGO KECAMATAN LUAK KABUPATEN LIMA PULUH KOTA PROVINSI SUMATERA BARAT (Blood Glucose Levels on Beagle (Canis familiaris) in Kenagarian Mungo, Luak District Lima Puluh Kota West Sumatera)

This research aimed to determine glucose levels of beagle maintained by Sports Association of Pig Hunting (PORBI) in Kenagarian Mungo Sub-district Luak District Lima Puluh Kota, West Sumatera. Blood samples were collected from 20 beagles. Blood sampling was performed during fasting time and two hours postprandial. Data were analyzed with analysis of Chisquare (x2). The results showed that mean glucose level in the fasting state beagle was 63.45±11.84 mg/dl and two hours postprandial was 93.45±12.52 mg/dl. The statistical test results showed no significant difference (P>0.05) between the frequency of feeding and supplementary feeding on blood glucose levels. To conclude, the average of beagle blood glucose levels is still in normal range. There is a difference in blood glucose between two hours postprandial and a fasting blood glucose levels and the difference between hunting frequency and giving multivitamins injection on blood glucose levels, but there was no difference on blood glucose levels between the frequency feeding and supplemental feeding.Key words: beagle, glucose levels, hunting, multivitamins