Spot on - both males and females disperse from their maternal 'groups' as orangutans are naturally independent and solitary. This can occur as young as six or seven for some orangutans, however most often stay longer than that. In captivity, it's not uncommon to see daughters remain with their mothers long term though, especially if the mother doesn't have any further offspring.With the birth of a new chimpanzee baby at Hamilton, and with Chiku and Kendi bound to transfer out in a few years, I'm wondering what the dispersal patterns are usually like for orangutans and what this will mean for Auckland Zoo.
Since Daya was imported, it looks as though either males or females can be transferred as the breeding programme requires. I personally hope to see Bahmi retained as breeding male, since there is a future possibility of Bahmi x Daya (as I've mentioned before, these two share a similar older female/younger male age gap as Madju and Luna in Florida). and a new female could also be sourced for Bahmi while Melur would be retired from the breeding programme.
I've heard it's often harder to place males overseas, although Bahmi would still be desirable due to his genetic value, and I personally believe that the best scenario for when Charlie passes on would be for Bahmi to eventually breed with Daya - an infant born to those two would also be very genetically valuable - and import another female.
Whereas with Daya's previous colony in the Netherlands, it would make more sense to transfer out Daya's younger brother, Sabar - he is a genetically valuable male, and any zoo would happily take him - and import a new male to breed with Jewel and Tjintha (and Minggu when she is of age).
With a relatively even birth sex ratio within this species in captivity, it's not surprising males are hard to place, especially out of the specific breeding program. There are consequently a lot of surplus males that have to be accommodated, and there's difficulty with this as unlike the other great ape species - bachelor groups can't be formed.
I can absolutely foresee Bahmi remaining as Auckland's next breeding male following his father's passing. If his mother and Daya's next offspring are both females though, and Charlie's still alive and kicking in say five or six years time - I'd imagine there might be consideration into transferring him to the USA, or even Europe.