This excellent range of three sets was "Produced in Cooperation with the Royal Society For The Protection of Birds". The RSPB logo is featured on each of them.
John Hunt (Product Manager at the time) tells us: "The very detailed artwork was by Peggy Chapman."
The first printing, GK216, was entitled "Birds of Britain"; when reprinted as L68 (& later as L97), the title was shortened to "Birds".
A full page advert from "Look-In" magazine, 3rd December 1977:
The display box, shown in the Thomas Salter 1981 trade catalogue:
Here are all three of the earlier title bundled together, just for a lark:
International editions (photos from Nic Comley):
Garden and Park: (L68/1a & L97/1)
View the others in this series here:
