During hibernation, mammalian cells are exposed to severe environmental stressors such as low temperature, lowered O 2 supply, and glucose deficiency. The cellular metabolic rate is markedly reduced for adapting to these conditions. AMP-activated protein kinase (AMPK) senses the cellular energy status and regulates metabolism. Therefore, we examined AMPK signaling in several brain regions and peripheral tissues in hibernating chipmunk. Eukaryotic elongation factor 2 (eEF2) is a downstream target of AMPK. Phosphorylation of eEF2, indicating its inactivation, is enhanced in the cerebral cortex of hibernating chipmunks. The study indicated that the sequential regulation of AMPK-mammalian target of rapamycin complex 1-eEF2 signaling was altered and protein synthesis ability was reduced in the cerebral cortex of hibernating chipmunks.

An acute and direct effect of epinephrine (Epi) on muscle proteolysis was investigated using a single-pass mode of rat hindquarter perfusion. The rate of tyrosine (Tyr) release at > 30 min with cycloheximide was regarded as the muscle proteolytic rate. Infusion of Epi (500 nM) to the hindquarters of fed rats led to a sharp decrease in the Tyr release to 50% within 5 min, accompanied by an increase in perfusion pressure and edema around the perfused tissues. To clarify the mechanism, alpha- and beta-antagonists were used together with Epi. A mixture of 10 microM prazosin and 10 microM yohimbine (alpha-adrenergic blockade) before or after Epi infusion completely prevented the edema development and resulted in a new steady state to 80% of the initial rate. On the contrary, 100 microM propranolol (a beta-antagonist) with Epi did not abolish the edema and caused fluctuation in Tyr release. Whether the above results are affected by changes in Tyr transport at the plasma membrane was tested by measuring Tyr efflux from the perfused muscle. Only a beta-adrenergic blockade significantly reduced the rate constant of Tyr efflux from the intracellular pool by 13%. These results suggested that the suppression of Tyr release by alpha-adrenergic activity was mainly due to the effect on Tyr efflux, whereas that by beta-adrenergic activity was not at the Tyr transport level but at the proteolysis level, demonstrating that Epi directly inhibits proteolysis of skeletal muscle via the beta-adrenoceptor.

Radar is a powerful technology for surveys of avian movements. Validating the accuracy of radar detection is an essential step when establishing quantitative criteria for counting bird flocks. Previous studies on accuracy verification have focused on trajectory data after tracking echoes. However, as tracking algorithms differ among researchers, so radar detection performance has not been accurately validated. This study clarifies the positional and biological factors that influence the probability of detection (POD) and area (pixel size) of echoes on X-band marine radar. As positional factors, distance was found to have a negative effect on POD and pixel size, while elevation angle was a positive effect on POD. We confirmed that biological factors included species differences (body weight, wingspan, and soaring behavior) and waterfowl flock size. Body weight and flock size positively affected POD and pixel size. In predicting detection performance, the survey distance required to achieve 50% POD was 750 m or less for Grey-faced Buzzard Butastur indicus (0.4 kg), the lightest target species, but up to 1800 m for a pair of Bewick’s Swan Cygnus (columbianus) bewickii. This study contributes to establishing more relevant criteria when setting the range of radar surveys and tracking algorithms of echoes.

A rapid increase in wind power generation has led to bird collisions becoming a serious problem worldwide. Developing useful sensitivity maps to select low‐risk sites for birds is an urgent issue. For migratory birds, such as geese and swans, that visit different habitats throughout their life cycle, it is important to conduct risk assessments that take into account their behavioural characteristics in each habitat. Geese and swans fly and migrate at varying altitudes (above the ground) ranging from 10 to hundreds of metres. Accurate predictions of avian flight altitudes are essential in assessing the risks of collisions with human‐made structures. We first obtained location data for four species of geese and swans to identify their spring migratory routes within Japan (Bean Goose Anser fabalis and Anser serrirostris, Greater White‐fronted Goose Anser albifrons, Tundra Swan Cygnus columbianus bewickii and Whooper Swan Cygnus cygnus). As all four species used the same roosts and overlapping foraging areas from winter to spring, a single migratory route was defined by integrating the location data of the four species. Flight trajectories were tracked using an ornithodolite. The median flight height for these four species in all landscape types was 150 m or less. Then a LASSO regression model was created with flight altitude obtained as the response variable and topographic and landscape factors as explanatory variables. Trends in flight altitude with environmental differences were similar for the four species, indicating that topographical factors strongly influence flight altitude. Finally, a statistical model was used to predict flight altitudes along migration routes. The sensitivity maps we generated showed that for all four species, most flight heights during spring were within the wind turbine range, suggesting that their risk of collision with wind turbines was greater along their migratory route. Sensitivity maps that accurately reflect avian flight characteristics help provide useful information when considering the location of further wind turbine construction.

No abstract