Biological characteristics of euphausiids preyed upon by Adelie penguin, Pygoscelis adeliae, breeding at Hukuro Cove, Lutzow-Holm bay in 1995/1996

Adelie penguins were used as a biological sampler from late December 1995 to late January 1996 to study biological characteristics of euphausiids in Lutzow-Holm Bay, which is generally covered with fast sea-ice even in summer. Stomach contents and diving behavior of the penguins were examined. Euphausiids accounted for 73% of total wet weight of stomach contents, and fish 27%. Among euphausiids, Euphausia superba occupied 83%, and E. crystallorophias 17%. Females occupied 96% of the total number of E. superba, males only 4%. E. crystallorophias consisted of 73% females, 10% males and 17% juveniles. Adelie penguins might eat nutritionally superior female euphausiids selectively, and/or they could not catch male euphausiids which can swim faster. It was suggested that those individuals which dived deeper ate more euphausiids than fish, and larger E. superba

Venous velocity of the right femoral vein decreases in the right lateral decubitus position compared to the supine position: a cause of postoperative pulmonary embolism?

The right lateral decubitus position is a risk factor for postoperative pulmonary embolism. We examined postural changes of femoral vein velocity in order to elucidate the mechanism. Thirty patients scheduled for general thoracic surgery were enrolled in this study. The common femoral veins on both sides were examined by color-duplex ultrasound for venous caliber and velocity when the patients were in the right lateral, left lateral, and supine positions. The maximum diameters of the right femoral vein in the right lateral decubitus position and the left femoral vein in the left decubitus position were significantly larger than those in the other positions. The venous velocity of the right femoral vein in the right lateral decubitus position was significantly smaller than that in the supine position, while the velocity of the left femoral vein in the left lateral decubitus position was not significantly decreased. We speculate that the decreased venous velocity of the right femoral vein in the right lateral decubitus position could result in a deep venous thromboembolism in the right leg, making this position a possible risk factor for postoperative pulmonary embolism.</p

Scaling of soaring seabirds and its implication for the maximum size of flying pterosaurs

The flight ability of animals is restricted by the scaling effects imposed by physical and physiological factors. In comparisons of the power available from muscle and the mechanical power required to fly, theoretical studies have predicted that the margin between the powers should decrease with body size and that flying animals have a maximum body size. However, predicting an absolute value of this upper limit has been difficult because wing morphology and flight styles vary among species. Albatrosses and petrels have long, narrow, aerodynamically efficient wings and are considered to be soaring birds. Here, using animal-borne accelerometers, we show that scaling analyses of wing-flapping frequencies in these seabirds indicate that the maximum size limit for soaring animals is a body mass of 41 kg and a wingspan of 5.1 m. Soaring seabirds were observed to have two modes of flapping frequencies: vigorous flapping during takeoff and sporadic flapping during cruising flight. In these species, high and low flapping frequencies were found to scale with body mass (_mass_ ^-0.30^ and _mass_ ^-0.18^) in a manner similar to the predictions from biomechanical flight models (_mass_ ^-1/3^ and _mass_ ^-1/6^). The scaling relationships predicted that animals larger than the limit will not be able to flap fast enough to stay aloft under unfavourable wind conditions. Our result therefore casts doubt on the flying ability of large, extinct pterosaurs. The largest extant soarer, the wandering albatross, weighs about 10 kg, which might be a pragmatic limit to maintain a safety margin for sustainable flight and to survive in a variable environment

European shags optimize their flight behavior according to wind conditions

Aerodynamics results in two characteristic speeds of flying birds: the minimum power speed and the maximum range speed. The minimum power speed requires the lowest rate of energy expenditure per unit time to stay airborne and the maximum range speed maximizes air distance traveled per unit of energy consumed. Therefore, if birds aim to minimize the cost of transport under a range of wind conditions, they are predicted to fly at the maximum range speed. Furthermore, take-off is predicted to be strongly affected by wind speed and direction. To investigate the effect of wind conditions on take-off and cruising flight behavior, we equipped 14 European shags Phalacrocorax aristotelis with a back-mounted GPS logger to measure position and hence ground speed, and a neck-mounted accelerometer to record wing beat frequency and strength. Local wind conditions were recorded during the deployment period. Shags always took off into the wind regardless of their intended destination and take-off duration was correlated negatively with wind speed. We combined ground speed and direction during the cruising phase with wind speed and direction to estimate air speed and direction. Whilst ground speed was highly variable, air speed was comparatively stable, although it increased significantly during strong head winds, because of stronger wing beats. The increased air speeds in head winds suggest that birds fly at the maximum range speed, not at the minimum power speed. Our study demonstrates that European shags actively adjust their flight behavior to utilize wind power to minimize the costs of take-off and cruising flight

The minimum air volume kept in diving Adelie penguins : evidence for regulation of air volume in the respiratory system

Penguins are outstanding divers. Particularly intriguing is the observation that they seem to dive on inspiration, which contributes to increasing oxygen stores but which increases their buoyancy. It has been concluded that buoyancy is a major factor in determining the energetics of shallow diving birds and there is a positive correlation between estimated air volume in the body (respiratory system and feathers) and the maximum depth in the dive of free-ranging penguins. However, it is not known whether the variation in the total air volume is caused by the variation in the air volume in the respiratory system or in plumage. In the present study, underwater weights of restrained Adelie penguins Pygoscelis adeliae (n=27 birds) were continuously measured in a experimental tank. The birds lost much air from their feathers within 1-2 min of submergence. The maximum weights in the water were used to calculate the minimum air volumes that diving birds are expected to have in their body. These volumes were compared with estimated air volumes from two free-ranging Adelie penguins. Most estimated values of the free-ranging birds were larger than values from the restrained birds, which indicates that variation in the former air volume is likely caused by the variation in the air in the respiratory system. Penguins seem to adjust the volume of air inhaled to the maximum depths of their dives

Why can they fly and swim? Dynamic similarity between flight and swimming in Rhinoceros auklets

第3回極域科学シンポジウム/第34回極域生物シンポジウム 11月26日（月） 国立極地研究所 ３階ラウン

Disentangling the migration phases during the non-breeding period reveals uneven carry-over effects to the subsequent breeding in a diving seabird

第6回極域科学シンポジウム[OB] 極域生物圏11月16日（月）　統計数理研究所 セミナー室1（D305