Seabird Sessions 20

grant-humphriesGrant RW Humphries
  • 21 Aug

Hi everyone,

Please circulate to anyone and/or everyone who might be interested.

20 sessions! Wow. Thanks so much to all of you, and to the seabird community (and of course the World Seabird Union) for continuing to support and attend Seabird Sessions. We certainly wouldn’t be able to engage in these amazing discussions without you.

Seabird Sessions 20 will occur on Wednesday, August 26th at 1600 GMT.
Our two papers for next week:

Collet, J. and Weimerskirch, H., 2020. Albatrosses can memorize locations of predictable fishing boats but favour natural foraging. Proceedings of the Royal Society B, 287(1932), p.20200958.
Abstract reads: Human activities generate food attracting many animals worldwide, causing major conservation issues. The spatio-temporal predictability of anthropogenic resources could reduce search costs for animals and mediate their attractiveness. We investigated this through GPS tracking in breeding black-browed albatrosses attracted to fishing boats. We tested for answers to the following questions. (i) Can future boat locations be anticipated from cues available to birds? (ii) Are birds able to appropriately use these cues to increase encounters? (iii) How frequently do birds use these cues? Boats were spatially persistent: birds searching in the direction where they previously attended boats would encounter twice as many boats compared with following a random direction strategy. A large proportion of birds did not use this cue: across pairs of consecutive trips (n = 85), 51% of birds switched their foraging direction irrespective of previous boat encounters. Still, 15 birds (27%) were observed to closely approach (approx. 0.1–1 km) where they previously attended a boat while boats were no longer there. This is less than the distance expected by chance (approx. 10–100 km), based on permutation control procedures accounting for individual-specific spatial consistency, suggesting individuals could memorize where they encountered boats across consecutive trips. We conclude albatrosses were able to exploit predictive cues from recent boat encounters but most favoured alternative resources.

Osborne, O.E., Hara, P.D., Whelan, S., Zandbergen, P., Hatch, S.A. and Elliott, K.H., 2020. Breeding seabirds increase foraging range in response to an extreme marine heatwave. Marine Ecology Progress Series, 646, pp.161-173.
Abstract reads: Marine heatwaves are increasing in frequency and can disrupt marine ecosystems non-linearly. In this study, we examined the effect of the North Pacific warming event of 2014, the largest long-term sea surface anomaly on record, on black-legged kittiwake Rissa tridactyla foraging trips before, during, and after the event. We assessed foraging trip characteristics (trip distance and duration), the dispersal of foraging locations, and the persistence of foraging areas within and among years. Foraging trip characteristics, foraging area size, and location varied from year to year. Kittiwake foraging was more dispersed, direct, and farther from the colony in years immediately after and during the warming event. A third of the foraging area used pre-heatwave (2012) was important in subsequent years, which indicates that this area was, and may still be, a perennial foraging hot spot. During the chick-rearing stage, black-legged kittiwakes increased their speed and reduced the proportion of resting compared to the incubation stage. We conclude that marine heatwaves may have a strong impact on seabird foraging, extending foraging ranges, and that those impacts may be nonlinear with a strong lag.

Looking forward to seeing you next week

Cheers
Grant and David