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Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2023,11,14]]},"abstract":"<jats:p>Unlike in many polar regions, the spatial extent and duration of the sea ice season have increased in the Ross Sea sector of the Southern Ocean during the satellite era. Simultaneously, populations of Ad\u00e9lie penguins, a sea ice obligate, have been stable or increasing in the region. Relationships between Ad\u00e9lie penguin population growth and sea ice concentration (SIC) are complex, with sea ice driving different, sometimes contrasting, demographic patterns. Ad\u00e9lie penguins undergo a complete molt annually, replacing all their feathers while fasting shortly after the breeding season. Unlike most penguin species, a majority of Ad\u00e9lies are thought to molt on sea ice, away from the breeding colonies, which makes this period particularly difficult to study. Here, we evaluate the hypothesis that persistent areas of high SIC provide an important molting habitat for Ad\u00e9lie penguins. We analyzed data from geolocating dive recorders deployed year-round on 195 adult penguins at two colonies in the Ross Sea from 2017 to 2019. We identified molt by detecting extended gaps in postbreeding diving activity and used associated locations to define two key molting areas. Remotely sensed data indicated that SIC during molt was anomalously low during the study and has declined in the primary molt area since 1980. Further, annual return rates of penguins to breeding colonies were positively correlated with SIC in the molt areas over 20 y. Together these results suggest that sea ice conditions during Ad\u00e9lie penguin molt may represent a previously underappreciated annual bottleneck for adult survival.<\/jats:p>","DOI":"10.1073\/pnas.2306840120","type":"journal-article","created":{"date-parts":[[2023,11,6]],"date-time":"2023-11-06T15:30:36Z","timestamp":1699284636000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":15,"title":["Sea ice concentration decline in an important Ad\u00e9lie penguin molt area"],"prefix":"10.1073","volume":"120","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6144-9950","authenticated-orcid":false,"given":"Annie E.","family":"Schmidt","sequence":"first","affiliation":[{"name":"Point Blue Conservation Science, Antarctica Program, Petaluma, CA 94954"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Am\u00e9lie","family":"Lescro\u00ebl","sequence":"additional","affiliation":[{"name":"Point Blue Conservation Science, Antarctica Program, Petaluma, CA 94954"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6399-0035","authenticated-orcid":false,"given":"Simeon","family":"Lisovski","sequence":"additional","affiliation":[{"name":"Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Polar Terrestrial Environmental Systems, Potsdam 14473, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Megan","family":"Elrod","sequence":"additional","affiliation":[{"name":"Point Blue Conservation Science, Antarctica Program, Petaluma, CA 94954"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5030-4289","authenticated-orcid":false,"given":"Dennis","family":"Jongsomjit","sequence":"additional","affiliation":[{"name":"Point Blue Conservation Science, Antarctica Program, Petaluma, CA 94954"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4148-246X","authenticated-orcid":false,"given":"Katie M.","family":"Dugger","sequence":"additional","affiliation":[{"name":"US Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Corvallis, OR 97331"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8604-7066","authenticated-orcid":false,"given":"Grant","family":"Ballard","sequence":"additional","affiliation":[{"name":"Point Blue Conservation Science, Antarctica Program, Petaluma, CA 94954"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2023,11,6]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1017\/9781009157964.001","volume-title":"The Ocean and Cryosphere in a Changing Climate: Special Report of the Intergovernmental Panel on Climate Change","author":"Intergovernmental Panel on Climate Change (IPCC)","year":"2022","unstructured":"Intergovernmental Panel on Climate Change (IPCC), \u201cSummary for policymakers\u201d in The Ocean and Cryosphere in a Changing Climate: Special Report of the Intergovernmental Panel on Climate Change, H.-O. 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Parmelee, W. R. Fraser, D. R. Neilson, Birds of the Palmer Station area. Antarct. J. U.S. 12, 15\u201321 (1977).","journal-title":"Antarct. J. U.S."},{"key":"e_1_3_4_66_2","doi-asserted-by":"publisher","DOI":"10.1111\/1365-2656.13036"},{"key":"e_1_3_4_67_2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0007324"},{"key":"e_1_3_4_68_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.2041-210X.2012.00248.x"},{"key":"e_1_3_4_69_2","doi-asserted-by":"publisher","DOI":"10.1525\/9780520328150-014"},{"key":"e_1_3_4_70_2","unstructured":"N. DiGirolamo C. L. Parkinson D. J. Cavalieri P. Gloersen H. J. Zwally Sea Ice concentrations from Nimbus-7 SMMR and DMSP SSM\/I-SSMIS passive microwave data version 2 (2022) 10.5067\/MPYG15WAA4WX (20 October 2021)."},{"key":"e_1_3_4_71_2","doi-asserted-by":"publisher","DOI":"10.1093\/auk\/123.3.858"},{"key":"e_1_3_4_72_2","volume-title":"Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach","author":"Burnham K. 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Dugger A full lifecycle approach to understanding Ad\u00e9lie Penguin response to changing pack ice conditions in the Ross Sea. US Antarctic Program Data Center. https:\/\/www.usap-dc.org\/view\/project\/p0010177. 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