thumbnail

Detecting denning polar bears with Forward-Looking Infrared (FLIR) imagery

BioScience

By:
, , , ,

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

Polar bears give birth in snow dens in midwinter and remain in dens until early spring. The survival and development of cubs is dependent on a stable environment within the maternal den. To mitigate potential disruption of polar bear denning by existing and proposed petroleum activities, we used forward-looking infrared (FLIR) viewing to try to detect heat rising from dens.We flew transects over dens of radio-collared females with FLIR imager-equipped aircraft, recorded weather conditions at each observation, and noted whether the den was detected.We surveyed 23 dens on 67 occasions (1 to 7 times each). Nine dens were always detected, and 10 dens visited more than once were detected on some flights but not on others. Four dens were never detected (17 percent), but three of those were visited only under marginal conditions. The odds of detecting a den were 4.8 times greater when airborne moisture (snow, blowing snow, fog, etc.) was absent than when it was present, and they increased 3-fold for every 1?C increase in temperature-dew point spread. The estimated probability of detecting dens in sunlight was 0. Data suggested that FLIR surveys conducted during optimal conditions for detection can produce detection rates approaching 90 percent and thus can be an important management and mitigation tool.

polar bear, infrared imagery, maternal denning, human impacts, management

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Detecting denning polar bears with Forward-Looking Infrared (FLIR) imagery
Series title:
BioScience
Volume
54
Issue:
4
Year Published:
2004
Language:
English
Contributing office(s):
Alaska Biological Science Center
Description:
pp. 337-344
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
337
Last page:
344
Number of Pages:
8