Importance of lunar and temporal conditions for spotlight surveys of adult black-footed ferrets

Western North American Naturalist
By: , and 



Black-footed ferrets (Mustela nigripes) spend most daylight hours underground in prairie dog (Cynomys) burrows and exhibit aboveground movements primarily at night. Moonlight can influence the activity patterns of ferrets and, consequently, might influence the efficiency of spotlight surveys used by biologists to monitor ferret populations. We related detection of adult ferrets during postbreeding spotlight surveys to lunar and temporal conditions. We most frequently located ferrets during surveys in which the moon breached the horizon. The data suggested intersexual differences in response to moonlight. We located male ferrets most frequently during nights with greater moon illumination, but we did not detect a correlation between moon illumination and spotlight detection of female ferrets. In general, moonlight could facilitate aboveground navigation by ferrets. However, it seems activity under bright moonlight could be costly for female ferrets while they raise young. Detection of ferrets also varied among months. We detected female ferrets most frequently in August–September, when mothers increase hunting efforts to acquire prey for growing offspring (kits). Detection of adult female ferrets declined in October, when kits were likely independent of their mother. We located male ferrets most frequently in September–October, when males might increase activity to monitor female ferrets and male competitors. Consideration of lunar and temporal influences and standardization of postbreeding surveys could enhance site-specific assessment of reintroduction success and across-site assessment of species recoveiy progress. We suggest that postbreeding surveys for ferrets should be enhanced by concentrating efforts in August–September during moonlit nights when the moon is above the horizon.
Publication type Article
Publication Subtype Journal Article
Title Importance of lunar and temporal conditions for spotlight surveys of adult black-footed ferrets
Series title Western North American Naturalist
DOI 10.3398/064.072.0207
Volume 72
Issue 2
Year Published 2012
Language English
Publisher Brigham Young University
Publisher location Provo, UT
Contributing office(s) Fort Collins Science Center
Description 12 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Western North American Naturalist
First page 179
Last page 190
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