One of the most dramatic birds ever exhibited at London Zoo stares down the lens with imperious authority — the Concave-casqued Hornbill, photographed by F. W. Bond in the aviaries of the Zoological Society of London, Regent's Park, in the early 1900s. The magnificent curved casque crowning its massive bill identifies this as a Southeast Asian species rarely seen in captivity, and Bond's crisp black-and-white study captures every feather texture with striking clarity. This is an Undivided Back (UDB) card — the message was required to go on the front, leaving the reverse clean except for the printed "THE ADDRESS ONLY TO BE WRITTEN HERE" instruction and a 1d stamp box — dating it to before the 1902 British divided-back regulation took effect, or issued slightly after but in UDB format. The ZSL issued a numbered series of animal postcards sold at the zoo gates; this is No. 5 of that series, a charming artifact of Edwardian natural history enthusiasm. Never mailed; no message.