Mixed marriages in birds

Ilsa Sharp from Perth, Western Australia, wrote on 21st February 2006: “I would like to ask whether anybody has encountered any 'inter-racial marriages' between different species of birds in Singapore, articularly between newcomer aliens and indigenous residents - and if so, are the offspring automatically infertile?

“This thought came to me because I was birding with Birds Australia's Western Australian chapter last weekend, on a bush track following the Swan River in Perth, and our experienced leader introduced us to a cute partnership between a Galah (a pretty pink and grey parrot, Cacatua roseicapilla) and a Corella (white cockatoo-like parrot) of the species (Long-billed – Cacatua tenuirostris) that has invaded Western Australia from Australia's eastern states. He said the birds had been together for 30 years already and had produced young, which were infertile.

“We stood and watched the unlikely pair feeding together on the ground for a while and they did indeed seem devoted to each other! Our leader was not sure which was the male, which the female, though he had seen the larger bird, the Corella, on the nest once.

Just intrigued to know what kind of mingling has been attempted in Singapore, if any.”

Our bird specialist, R. Subaraj replied: “Your Cockatoo mixed species pairing is most interesting. Particularly since the Galah is not an uncommon bird there and he/she should not have been short of partners.

“The current wave of thought in South-West Australia is that all birds of the three species of corella around Perth (Little, Long-billed and Western) are feral (originate from escapees). The natural populations of the first two species don't come anywhere close to western Australia while the Western may have been native around Perth in the past but went extinct, so the current birds are considered feral. The native population is supposed to be further north of Perth. At least this is what I have read.

“If this is true, then the Long-billed Corella in the mixed pair may not have had a mate of the same species 30 years ago and paired off with the Galah.

“All reports that I have heard of with regards to mixed species pairing have the offspring being infertile. If they are fertile, then the two species involved must be subspecies rather than species.

“In Singapore, there have been records of Common/Javan Myna offspring with the bird being grey with a yellow eye-patch (Kang Nee pers. comm.). However, I cannot recall other strange pairings involving native species. At present, a lone female Rhinoceros Hornbill (Buceros rhinoceros), who has been at Bukit Timah for more than a year, has apparently found a partner in the form of a female Great Hornbill (B. bicornis)... and they have been seen prospecting potential nest holes around Hindhede Quarry!”

Contributed by Ilsa Sharp and R. Subaraj. Top image of Tanimbar Corella and bottom of Rhinoceros and Great Hornbills by YC

Ilsa wrote on 25th April 2006: "Remember that posting I made earlier regarding 'mixed marriages' among birds - my original observation being the longterm relationship between a Galah and a Corella cockatoo in Western Australia? Well, sorry for the long lapse in time, but I have now got a photo of the happy couple, attached! For those who don't know, the Galah is the pink and grey one, pretty but there are suspicions that the big white Corella may actually be the female! Thanks to WA birder Ted Cawley for the photo. Ilsa, Perth, Western Australia