Amsterdam Swans™
Schemes to brand Amsterdam started well before the I Amsterdam campaign. In the late 1950s, says city ecologist Geert Timmermans, the Amsterdam city council released several Mute swans (Cygnus olor) around the Sloterplas in Amsterdam West. Before being set free, the black bills of these cygnets were apparently marked (or branded) with the insignia of Amsterdam: 3 Andreaskruizen (3 Saint Andrew’s crosses). This tattoo would only become visible once the swan matures and its bill turns orange. This branding scheme was possibly also a means to protect the swans from being poached by swan hungry folks.
If anyone has any photographic material of this baffling bill branding strategy (a city being proprietarian about its swans!) leave a comment on Geheugen van West