They hybridize with them, too. I saw an Eastern Rosella/Red-crowned Parakeet 'mule' hybrid at Somes Island a while ago.
Thats interesting...
The only other instance I have ever heard of was a breeder in the UK some 10 years ago claiming with photos of hybridizing kakariki and Eastern Rosella....he claimed they did so naturally.
Personally and the opinion is also held by leading kakariki breede4rs in The Netherlands, Belgium and Australia that to do so would entailing force breeding... an opinion I still maintain, based on close observation over many years.
Althu we obtained photos taken over a period of time of both parents and chicks to adulthood, a any questions and queries we (breeders above, and myself) made where never replied to.
Such an event withing the breeding world is of huge interest....as the case of the blue mutaion RC kakariki, now successfully breed in Europe, and the red , red crown kakariki .....Both of which have now been substantiated in resent months.
The original 'blue ' I observed in Aussie some years ago but believe that was due to diet or poor health issues... it died not long after and the breeder disappeared ....
Kakariki at best are quite fussy when it comes to choosing a mate, both the male and female... but once paired up they breed like rabbits.
Im sure I have the pics of the engilish hybrid on an old hard drive from an old computer here somewhere.