스킵네비게이션

○강 연 일 : 2017년 10월 18일(수)

○강 연 자 : 이 원 영박사(극지연구소 극지생명과학연구부 선임연구원)

○강연내용

-남극 킹조지섬 소개

-펭귄의 잠수, 수영, 취식행동

-펭귄 연구를 위한 바이오로깅 기술

-남극 생태계 보존을 위한 노력

Behavioral ecology studies on marine birds in King George Island, Antarctica

Many marine birds dive to catch prey in water. The gentoo penguin (Pygoscelis papua), a specialized diving seabird that preys on krill and fish, is distributed from the sub-Antarctic islands to Antarctic regions. Here, we observed the diving behavior of breeding gentoo penguins on King George Island, South Shetland Islands, Antarctica. Using a time?depth recorder (TDR), we collected diving depths every second from seven gentoo breeders for 5?21 days during the chick-rearing period and analyzed their diving characteristics. No significant differences in diving characteristics were detected between sexes. Most dives occurred in shallow water, although the dive efficiency (= proportion of bottom duration time in one dive cycle) was highest at depths of 30?35 m and decreased as the penguins dove deeper. Gentoo penguins did not dive more frequently during the day than at night, but during nighttime, most dives occurred in shallow water (< 20 m) and the dive efficiency was also higher at this time. As penguins repeated their foraging trips, the number of dives, depth of dives, and trip duration did not change significantly. Our results suggest that the diel dive patterns of gentoo penguins might be related to the vertical migration of krill (upward to the surface at night). In addition, we observed that gentoo penguins could perform active diving behavior even at night, possibly aided by civil twilight during the chick-rearing period in Antarctic regions.

In decades, the glaciers on the Antarctic Peninsula have been rapidly retreating. In this study, Using selected satellite images during the austral summer from 1989 to 2015, we estimated the glacier retreat pattern in on the Barton Peninsular, King George Island, Antarctica, which is bounded by the Fourcade glacier. Also, during three breeding seasons (2012-2013, 2013-2014, 2014-2015), we recorded the breeding nests of kelp gulls in this glacier-retreat region. According to 1989?2015 satellite images, glacier boundaries have gradually retreated and we observed about 30 kelp gull nests in areas newly exposed. The glacial retreat has exposed many moraine surfaces, formed from glacial debris of soil and rock, and kelp gulls were found surrounded by several rocks. We thus hypothesize that rocks in the scattered moraines play an important role in the breeding sites of kelp gulls because they may protect against strong winds. Our satellite images and records of newly established kelp gull nests in our study site suggest that glacier retreat could lead to an enlarged breeding habitat for kelp gulls.

Recent findings report that wild animals can recognize individual humans. To explain how the animals distinguish humans, two hypotheses are proposed. The high cognitive abilities hypothesis implies that pre-existing high intelligence enabled animals to acquire such abilities. The pre-exposure to stimuli hypothesis suggests that frequent encounters with humans promote the acquisition of discriminatory abilities in these species. Here, we examine individual human recognition abilities in a wild Antarctic species, the brown skua (Stercorarius antarcticus), which lives away from typical human settlements and was only recently exposed to humans due to activities at Antarctic stations. We found that, as nest visits were repeated, the skua parents responded at further distances and were more likely to attack the nest intruder. Also, we demonstrated that seven out of seven breeding pairs of skuas selectively responded to a human nest intruder with aggression and ignored a neutral human who had not previously approached the nest. The results indicate that Antarctic skuas, a species that typically inhabited in human-free areas, are able to recognize individual humans who disturbed their nests. Our findings generally support the high cognitive abilities hypothesis, but this ability can be acquired during a relatively short period in the life of an individual as a result of interactions between individual birds and humans.