The photos from Canada in the public domain section are collected from 35mm film slides that Dudley and Hilary left behind.
Dudley Foskett was a Park Naturalist (BA & MA in Biology)
Hilary Bastin Foskett was a Botanist (BSc in Botany)
Most of their work was in the Western Canadian National Parks. All west of the Manitoba/Ontario provincial border.
As for taking photos, they both had identical Pentax cameras. All aerial photos and a small number of the other photos are made by Dudley. The rest of the photos (larger part), especially flowers and plants, are made by Hilary.