Differences in Rhinoceros Auklet diet and chick body mass at 4 breeding sites in Hokkaido

In spring, long-distance migrants are considered to adopt a time-minimizing strategy to promote early arrival at breeding sites. The phenology of spring migration was examined and compared between two insular stopover sites in Greece and Sweden for Icterine Warbler, Wood Warbler, Spotted Flycatcher and Collared Flycatcher. All of them migrate due north which means that some proportion of birds that pass through Greece are heading to Scandinavia. The Collared Flycatcher had the earliest and the Icterine Warbler the latest arrival time. The differences in median dates between Greece and Sweden were 3–4 weeks and the passages in Sweden were generally more condensed in time. The average overall speed estimates were very similar and varied between 129 and 137 km/d. In most of the species higher speed estimates were associated with years when birds arrived late in Greece. After crossing continental Europe birds arrive at the Swedish study site with significantly higher body masses compared to when they arrive in Greece and this might indicate a preparation for arriving at breeding grounds with some overload.

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Migratory strategies of juvenile northern fur seals (Callorhinus ursinus): bridging the gap between pups and adults

Scientific Reports ◽

10.1038/s41598-019-50230-z ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Tonya Zeppelin ◽

Noel Pelland ◽

Jeremy Sterling ◽

Brian Brost ◽

Sharon Melin ◽

...

Keyword(s):

Body Mass ◽

Environmental Variability ◽

North Pacific Ocean ◽

Diving Behavior ◽

Callorhinus Ursinus ◽

Differential Migration ◽

Breeding Sites ◽

Demographic Groups ◽

Migratory Strategies ◽

Similar Body

Abstract In species exhibiting differential migration by sex and age, understanding what differences exist, and the adaptive reasons for these differences is critical for determining how demographic groups will respond to environmental variability and anthropogenic perturbations. We used satellite-telemetered movement and diving data to investigate differential migration and its ontogeny in a highly migratory North Pacific Ocean predator, the northern fur seal (Callorhinus ursinus; NFS), with a focus on understudied juvenile (1- to 2-year-old) animals. We instrumented 71 juvenile NFS in two years (2006–07 and 2007–08) at three major North American breeding sites and compared their migratory strategies with pups and adults. Although sexual dimorphism is strong in adult NFS, only weak differences in body mass between sexes were found in juveniles, which had similar body mass to pups (~3–4 months). However, unlike widely-dispersed pups, juvenile male and female NFS dispersed in different directions, and used different habitats characterized by distinct hydrography and prey assemblages during migration, similar to breeding adults. Juvenile diving behavior differed only modestly among habitats and between sexes, consistent with weak differences in body mass. Evidence of habitat sexual segregation by juvenile NFS contradicts previous hypotheses that physiological differences predominantly drive the ontogeny of differential migration.

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Morphometrics of Flightlessness in the Alcidae

The Auk ◽

10.1093/auk/105.4.681 ◽

1988 ◽

Vol 105 (4) ◽

pp. 681-698 ◽

Cited By ~ 63

Author(s):

Bradley C. Livezey

Keyword(s):

Body Mass ◽

Published Data ◽

Large Core ◽

Wing Area ◽

Alca Torda ◽

Breeding Sites ◽

Large Size ◽

Mass Estimate ◽

Recent Species ◽

Extreme Specialization

Abstract Data collected from skin specimens of the 23 Recent species of Alcidae, skeletal material for Recent and fossil alcids, and published data on body mass and wing area were used to describe the morphometric characteristics of flightlessness in the Great Auk (Pinguinus impennis) and the fossil mancalline auks. A regression equation confirmed a body-mass estimate (5 kg) for P. impennis (Bédard 1969). The size and relatively small wings produced wing-loading of roughly 22 g· cm-2, comparable to those of medium-sized penguins. Multivariate analysis of external measurements underscored the uniquely large size, relatively short wings, and moderately deep bill of Pinguinus compared to other Recent alcids. Analysis of skeletal measurements revealed that the genera of flightless Alcidae (Pinguinus, Mancalla, Praemancalla, and Alcodes) were characterized by relatively short distal wing elements and dorsoventral flattening of all major wing elements, in combination with relatively large core and pelvic dimensions. These differences were most pronounced in Mancalla, moderately developed in Praemancalla, and smallest in Pinguinus. Estimated body mass (1-4 kg) for selected fossil mancallines exceeded the largest flighted alcids (Uria) but was less than for Pinguinus. Pinguinus was a comparatively large piscivore sharing many morphological features with the Razorbill (Alca torda) and murres (Uria spp.). Its flightlessness evidently was a consequence of extreme specialization for pursuit diving, convergent with that of the Spheniscidae. Loss of flight imposed significant requirements on breeding sites and foraging habitats of the Great Auk and presumably the mancallines, and rendered Pinguinus exceptionally vulnerable to human exploitation.

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Agricultural land use and human presence around breeding sites increase stress-hormone levels and decrease body mass in barn owl nestlings

Oecologia ◽

10.1007/s00442-015-3318-2 ◽

2015 ◽

Vol 179 (1) ◽

pp. 89-101 ◽

Cited By ~ 17

Author(s):

Bettina Almasi ◽

Paul Béziers ◽

Alexandre Roulin ◽

Lukas Jenni

Keyword(s):

Land Use ◽

Body Mass ◽

Agricultural Land ◽

Barn Owl ◽

Agricultural Land Use ◽

Stress Hormone ◽

Breeding Sites ◽

Human Presence ◽

Hormone Levels

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Field and laboratory metabolism and thermoregulation in rhinoceros auklets

PeerJ ◽

10.7717/peerj.11460 ◽

2021 ◽

Vol 9 ◽

pp. e11460

Author(s):

Aika Umeyama ◽

Yasuaki Niizuma ◽

Masaki Shirai

Keyword(s):

Resting Metabolic Rate ◽

Breeding Sites ◽

Lower Critical Temperature ◽

Daily Energy ◽

Cerorhinca Monocerata ◽

Doubly Labeled Water Method ◽

Time Of Year ◽

The Cost ◽

Free Ranging ◽

Rhinoceros Auklet

Seabirds spend most of their lives at sea, except when visiting their breeding sites. Since the thermal conductivity of water is 25 times higher than that of air, seabirds resting on water lose heat and expend a considerable amount of energy for thermoregulation. For example, rhinoceros auklet (Cerorhinca monocerata), a medium-sized (480–620 g) alcid, spends most of its time floating on the sea. In order to estimate the cost of this behavior in terms of their daily energy expenditure (DEE), we studied rhinoceros auklets breeding on Teuri Island, Hokkaido Japan. We measured their resting metabolic rate (RMR) in air and on water by respirometry, and estimated their DEE by the doubly labeled water method. While RMR on water did not vary significantly between 10 °C and 15 °C, it was significantly higher at 5 °C. Air temperature (5.0–20.0 °C) had no effect on RMR. The DEE of free-ranging auklets averaged 1,005.5 kJ day−1 (±130.2, n = 3). Our results indicate that RMRs are elevated for auklets resting on water, particularly below their lower critical temperature (LCT), compared with in air. Accordingly, spending time above their LCT on water at any time of year will provide enhanced benefits, particularly to seabirds such as rhinoceros auklets which rest a considerable amount of time on water.

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