Forward-looking infrared radiometer (FLIR)

Abstract

We determined the probability of forward-looking infrared radiometer (FLIR) mounted in a fixed-wing airplane to detect and verify moose (Alces alces). This purpose was to determine the potential for using FLIR for a modified Gasaway et al (1986) ratio estimates based on low and high intensity aerial surveys for moose population surveys.

Area

The study area was located in northern New Hampshire within mixed deciduous-coniferous forests. The survey was conducted using FLIR mounted on a twin engine Chieftain fixed-winged aircraft during daylight hours flying transects at 600 m above ground level at 90 knots. The FLIR look angle was oriented at 45 –50o using a slight side-to-side sweep to search the 300 m wide belt transect. Low intensity surveys used transects spaced at 300 m apart while the high intensity transects were spaced 150 m wide allowing overlap of the adjacent transect. A total of 25 samples were obtained using radio-collared moose as the sample unit. The FLIR detected and distinguished moose in all cover types within the study area. Data were collected over 3 days with 88% of the moose detected in the low intensity search pattern and 96% in the high intensity search pattern.

Transect Layout

Transect layout for low and high intensity survey within a subplot (yellow) where a radio-collared moose (orange) was identified within the study area. An array of transects flight lines was plotted 500 ft apart across the study area and numbered consecutively. Each flight line represents a belt transect 1,000 ft wide. A low intensity survey consisted of a set of 3 transects (purple) selected to surround the subject moose but not provide overlap of the belt transects. A high intensity search included 2 additional transect (blue) providing overlap of the adjacent transect.