British Birds

Series of interlocking plywood jigsaw puzzles depicting artistic studies of British Birds, all thought to be by the British artist Roland Green (1896-1972).
Interestingly, whilst these appear to be very uncommon, they were clearly produced in several differing sets. My first example, entitled Redstart, albeit it's actually a Goldfinch, had a black & white image on the cover showing the various series produced and stating that they were of 30 pieces. These also included: Foreign Birds; Popular Show Dogs and Historical Ships. My second example, The Red-Backed Shrike, featured a colour image on the lid, which does not actually include this image, so the actual number in the series seems unclear. These were of 36-piece construction.