Seabird Sessions 28 - Swimmers and Flyers

grant-humphriesGrant RW Humphries
  • 8 Jan

Hi everyone, HAPPY NEW YEAR!

Seabird Sessions 28 is going ahead Wednesday the 13th of January at 1700 GMT

We've got a paper on an updated assessment of chinstrap penguin populations, and another on muscle ultrastructure.

ZOOM link will be available online at www.seabirds.net/events/seabird-sessions

Lalla, K.M., Whelan, S., Brown, K., Patterson, A., Jimenez, A.G., Hatch, S.A. and Elliott, K.H., 2020. Accelerometry predicts muscle ultrastructure and flight capabilities in a wild bird. Journal of Experimental Biology, 223(22).
Abstract: Muscle ultrastructure is closely linked with athletic performance in humans and lab animals, and presumably plays an important role in the movement ecology of wild animals. Movement is critical for wild animals to forage, escape predators and reproduce. However, little evidence directly links muscle condition to locomotion in the wild. We used GPS-accelerometers to examine flight behaviour and muscle biopsies to assess muscle ultrastructure in breeding black-legged kittiwakes (Rissa tridactyla). Biopsied kittiwakes showed similar reproductive success and subsequent over-winter survival to nonbiopsied kittiwakes, suggesting that our study method did not greatly impact foraging ability. Muscle fibre diameter was negatively associated with wing beat frequency, likely because larger muscle fibres facilitate powered flight. The number of nuclei per fibre was
positively associated with average air speed, likely because higher power output needed by faster-flying birds required plasticity for muscle fibre recruitment. These results suggest the potential for flight behaviour to predict muscle ultrastructure.

Strycker, N., Wethington, M., Borowicz, A., Forrest, S., Witharana, C., Hart, T. and Lynch, H.J., 2020. A global population assessment of the Chinstrap penguin (Pygoscelis antarctica). Scientific reports, 10(1), pp.1-11.
Abstract: Using satellite imagery, drone imagery, and ground counts, we have assembled the first comprehensive global population assessment of Chinstrap penguins (Pygoscelis antarctica) at 3.42 (95th-percentile CI: [2.98, 4.00]) million breeding pairs across 375 extant colonies. Twenty-three previously known Chinstrap penguin colonies are found to be absent or extirpated. We identify five new colonies, and 21 additional colonies previously unreported and likely missed by previous surveys. Limited or imprecise historical data prohibit our assessment of population change at 35% of all Chinstrap penguin colonies. Of colonies for which a comparison can be made to historical counts in the 1980s, 45% have probably or certainly declined and 18% have probably or certainly increased. Several large colonies in the South Sandwich Islands, where conditions apparently remain favorable for Chinstrap penguins, cannot be assessed against a historical benchmark. Our population assessment provides a detailed baseline for quantifying future changes in Chinstrap penguin abundance, sheds new light on the environmental drivers of Chinstrap penguin population dynamics in Antarctica, and contributes to ongoing monitoring and conservation efforts at a time of climate change and concerns over declining krill abundance in the Southern Ocean.