A study by the Dutch bird protection agency Vogelbescherming has revealed that there is a big problem with illegally caught wild birds in the Netherlands. Nests are robbed and the hatchlings are sold at bird shows and markets and over the internet.
The illegal trade of wild birds has been investigated more thoroughly since the subject was brought before the European Court in 1996. Since that time legally traded birds must be ringed. According to Vogelbescherming, the ringing process has been circumvented with illegal and forged rings.
Source: Wilde vogels zijn vogelvrij