The pheasants were brought to Europe already by the acient Greeks. Also the Romans loved the taste of pheasant-meat and afther the fall of the Roman Emperium monks and aristrocats started to breed pheassants for food.
In the year 1050 pheasants were already known in England and around 1250 they were common as wild birds in Germany. The pheasants found in Europe are a mix of al kinds of subspecies and its normal to find both birds with a whithe collar and birds without in the same population.
Many pheasants are reared and released each year by gamekeepers in England for 'sport'. These birds are often quite tame. However relatively few are taken by tigers