Here are the articles regarding French molt/moult in budgerigars. According to our PCR and Real-time PCR analyses for the past 25 years, classical french molt in budgerigars is caused by the PBFD virus and not avian polyomavirus. This is contradictory to some other sources on the Internet. The reason for this misconception is early work done in the 1980ies (G Bernier, M Morin, G Marsolais) on sick budgerigars where some had avian polyomavirus, but the PBFD virus was not identified until the early 1990ies. We detected it in all cases of french molt as early as 1999/2000 by conventional PCR. Our findings were published in the journal "Budgerigar World" in 2001.