Dual analysis of both colour and black and white photos resulted in the 
most complete evaluation. The characteristics of slope, altitude and 
aspect are equally recognisable in colour and black and white, but 
vegetation was more clearly examined by varying hues and intensities of 
colour. This is especially important in study areas such as this one, 
where tree cover is sparse and the major portion of the area is alpine, 
with low herbaceous and woody cover. On the other hand, black and 
white photos made cliff structure more apparent and distinct form was 
exaggerated by shadow. Shadows on colour photos often muddied the 
colour and made the images less clear. 
During analysis, it became abundantly clear that the known lambing areas 
were far superior to other sites. The central Ogilvie sites were 
especially unsuitable. It is unfortunate that no prime sites were 
identified in that range. No record of lambing has been made in that 
range (Stewart 1981) but sheep are known to be attracted to mineral 
licks at the road's edge. Perhaps the sheep lamb distant to the highway. 
The mountains within this portion of the highway corridor are low and 
altitude was much more of a limiting factor that in the south Ogilvies. 
Sites C6, C12 and C17, though, are sites were field investigations can 
begin. 
No field work was conducted after air photo interpretation in this study. 
This does not mean that ground truthing is unnecessary. The accuracy of 
the technique can only be tested in the field. It cannot stand alone. 
The author's knowledge of the area prior to interpreting the photos was 
important as an aid to evaluation, but does not remove the need for 
field work. It is not necessary to have prior knowledge of the area to 
be studied. Any investigator, armed with a good knowledge of sheep 
ecology, should be able to at least order priorities for areas to be 
studied in the field, or at most, pinpoint the most suitable lambing 
sites in the area. And, as a result of air photo interpretation, that 
field time should be reduced and more productive. 
Air photo interpretation is a fast, economical and reasonably accurate 
aid to the identification of critical areas of Dali's sheep habitat. 
I see no reason why it cannot be extended to other wildlife species. 
With careful application in environmental impact assessment, it will 
hopefully permit the identification of critical areas earlier in 
project planning. Then, any potential impacts can be mitigated at the 
preliminary design stage, and the continuing existence of wildlife 
populations assured. 
ACKNOWLEDGMENTS 
The author would like to thank V. Geist, G.A. Ross and R. Eccles for 
the assistance.