Remote identification of polar bear maternal den habitat in northern Alaska

George M. Durner; Steven C. Amstrup; Ken J. Ambrosius

doi:10.14430/arctic770

Home/Archive/USGS

USGS · 70024240

Remote identification of polar bear maternal den habitat in northern Alaska

George M. Durner·Steven C. Amstrup·Ken J. Ambrosius

View original source ↗Export metadata ↓

Abstract

Polar bears ( Ursus maritimus ) give birth in dens of ice and snow to protect their altricial young. During the snow-free season, we visited 25 den sites located previously by radiotelemetry and characterized the den site physiognomy. Seven dens occurred in habitats with minimal relief. Eighteen dens (72%) were in coastal and river banks. These "banks" were identifiable on aerial photographs. We then searched high-resolution aerial photographs (n=3000) for habitats similar to those of the 18 dens. On aerial photos, we mapped 1782 km of bank habitats suitable for denning. Bank habitats comprised 0.18% of our study area between the Colville River and the Tamayariak River in northern Alaska. The final map, which correctly identified 88% of bank denning habitat in this region, will help minimize the potential for disruptions of maternal dens by winter petroleum exploration activities.

Explore related subjects

Arctic Article

Source-reported bounding extent: 68.89797093471142° to 70.6985528072185° latitude; -151.72292652172834° to -140.72918403438467° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

George M. Durner, Steven C. Amstrup, Ken J. Ambrosius. 2001-01-01. Remote identification of polar bear maternal den habitat in northern Alaska. https://doi.org/10.14430/arctic770

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2022

Newly documented behavior of free-ranging Arctic wolf pups

Whereas much is known about the behavior and development of captive young wolf ( Canis lupus ) pups, less detail has been published about some aspects of free-ranging wolf pup behavior. This article synthesizes 42 observations of free-ranging Arctic wolf pups from ages 13 through 52 days made during 10 summers from 1987 through 2006 on Ellesmere Island, Nunavut, Canada. Besides listing key behaviors such as howling and caching, I record unique observations of ages of pup urination without adult stimulation (22, 33, 42, 52 days), knowledge of which is important to studies of wolf domestication, and of a 48-day-old pup that traveled 39 km during a 12 h and 19 min round trip between the den and a prey carcass, including a 26.5 km trek in 5 h. These observations should lead to a deeper and more complete understanding of this critical period of pup growth and development.

Nunavut↗

USGS2022

Kittlitz’s murrelet seasonal distribution and post-breeding migration from the Gulf of Alaska to the Arctic Ocean

Kittlitz’s Murrelets ( Brachyramphus brevirostris ) nest during summer in glaciated or recently deglaciated (post-Wisconsin) landscapes. They forage in adjacent marine waters, especially those influenced by glacial meltwater. Little is known of their movements and distribution outside the breeding season. To identify post-breeding migrations of murrelets, we attached satellite transmitters to birds (n = 47) captured at sea in the Gulf of Alaska and Aleutian Islands during May – July 2009 – 15 and tracked 27 birds that migrated from capture areas. Post-breeding murrelets migrated toward the Bering Sea, with short periods of movement (median 2 d) separated by short stopovers (median 1 d). Travel speeds averaged 79.4 km d-1 (83.5 SD, 449.1 maximum). Five Kittlitz’s Murrelets tagged in Prince William Sound in May migrated to the Bering Sea by August and four continued north to the Arctic Ocean, logging 2500 – 4000 km of travel. Many birds spent 2‒3 weeks with little movement along coasts of the Alaska Peninsula or eastern Bering Sea during late August through September, also the pre-basic molt period. Ship-based surveys, many of which were conducted concurrently with our telemetry studies, confirmed that substantial numbers of Kittlitz’s Murrelets migrate into the Arctic Ocean during autumn. They also revealed that some birds spend winter and spring in the Bering Sea in association with ice-edge, polynya, or marginal ice zone habitats before returning to summer breeding grounds. We conclude that this species is best characterized as a sub-Arctic and Arctic species, which has implications for future risk assessments and threat mitigation.

Alaska↗

USGS2021

Iñupiaq knowledge of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska

Successful wildlife management depends upon coordination and consultation with local communities. However, much of the research used to inform management is often derived solely from data collected directly from wildlife. Indigenous people living in the Arctic have a close connection to their environment, which provides unique opportunities to observe their environment and the ecology of Arctic species. Further, most northern Arctic communities occur within the range of polar bears ( nanuq , Ursus maritimus ) and have experienced significant climatic changes. Here, we used semi-structured interviews from 2017 to 2019 to document Iñupiaq knowledge of polar bears observed over four decades in four Alaskan communities in the range of the Southern Beaufort Sea polar bear subpopulation: Wainwright, Utqiaġvik, Nuiqsut, and Kaktovik. All but one of 47 participants described directional and notable changes in sea ice, including earlier ice breakup, later ice return, thinner ice, and less multiyear pack ice. These changes corresponded with observations of bears spending more time on land during the late summer and early fall in recent decades—observations consistent with scientific and Indigenous knowledge studies in Alaska, Canada, and Greenland. Participants noted that polar bear and seal body condition and local abundance either varied geographically or exhibited no patterns. However, participants described a recent phenomenon of bears being exhausted and lethargic when arriving on shore in the summer and fall after extensive swims from the pack ice. Further, several participants suggested that maternal denning is occurring more often on land than sea ice. Participants indicated that village and regional governments are increasingly challenged to obtain resources needed to keep their communities safe as polar bears spend more time on land, an issue that is likely to be exacerbated both in this region and elsewhere as sea ice loss continues.

Alaska↗