Wildlife and Conservation Day. And the discovery of the Atiu Swiftlet, a unique bird species found only in the Cook Islands. Only 100 silver proof covers were issued worldwide, making this one of the rarest of all Cook Islands philatelic-numismatic covers. Wildlife and Conservation Day / Atiu Swiftlet Bird. 50% Silver, 50% Copper. 27.97 g approx. 0.45 troy oz total weight. 13.99 g (? 0.45 × 0.50) = 0.45 × 0.925? 0.45? No?? 0.45 troy oz × 0.5 = 0.225 troy oz pure silver (7.0 g). Queen Elizabeth II (Arnold Machin portrait). “Swiftlet of Atiu in Flight, ” surrounded by fifteen stars representing the 15 Cook Islands design by James Berry, O. “RAROTONGA COOK ISLANDS, 15 NOV 1977 – First Day of Issue”. 100 Silver Proof covers (extremely limited issue). 1977 marked both Cook Islands Wildlife and Conservation Day and the Bicentennial of Captain Cook’s discovery of Atiu. The featured bird, the. , was newly documented by ornithologist David Holyoak of the UK. This coin is one of very few issues worldwide celebrating a newly discovered species. The item pictured is authentic and is the item you will receive. Thank you and good luck. Any statement regarding grading and condition are subjective and represent our best opinion. Please make sure to take a close look at the pictures to judge for yourself. All coins and paper currency are stored in coin flips and/or semi-rigid bill holders. We do not end auctions early.