Open AccessDoes survey effort influence sightability of mountain goats Oreamnos americanus during aerial surveys?
Author(s) -
Poole Kim G.
Publication year - 2007
Publication title -
wildlife biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.566
H-Index - 52
eISSN - 1903-220X
pISSN - 0909-6396
DOI - 10.2981/0909-6396(2007)13[113:dseiso]2.0.co;2
Subject(s) - aerial survey , geography , vegetation cover , vegetation (pathology) , survey methodology , survey research , range (aeronautics) , ecology , physical geography , biology , cartography , socioeconomics , land use , medicine , engineering , pathology , aerospace engineering , sociology
Practical techniques to estimate the sightability of mountain goats Oreamnos americanus during aerial surveys have not been developed or have been poorly tested. I evaluated sightability of 28 radio‐collared goats in two study areas in southeastern British Columbia to assess whether sightability increased with increased helicopter survey effort, and to explore which factors might affect sightability. Three surveys at different survey efforts were conducted in each study area, during which attempts were made to locate collared goats 64 times. I detected no relationship between survey effort in the range tested (1.3‐6.1 minutes/km 2 ) and sightability (38‐83%). Sightability averaged 63%. Only animal activity and larger group size influenced goat sightability. Sightability tended to decrease with increased vegetation cover. Survey efforts of > 2.0 minutes/km 2 do not appear to result in higher sightability. For surveys of large areas not well‐known to surveyors, a 60‐65% sightability correction may be realistic, with a target of approximately 1.5 minutes/km 2 effort.