powerful owl, currawongs

Thanks Yarden for the calls of barking owl and powerful owl. The call I heard at Monga had the same notes as the powerful owl call, ie length of notes, but seemed deeper. And more consistent woo woooo, rather than wou wohwoo. Didn't sound at all like the barking owl calls, but roughly the right pitch. So I guess I am still unsure. I heard the owl from the fern gully ~1km from the entrance to Monga at about 7pm.

 

On Currawongs, I find the explanations a little difficult to follow by Michael L and Jack. But some points:

Evolutionary and ecological theory discarded in the 1970s 'internal population regulation', ie that individuals would control each other thus maintaining the population. They now believe in the selfish gene. Interpreting this in this context would mean currawongs target any birds nests for their own benefit of food, including currawongs.

 

An explanation for why a stranger 'might' care for another birds young could be to gain a mate and/or a territory.

 

What is the purpose of currawong autumn calls?? I still havent heard a definitive answer. Perhaps it is to bring birds together to find mates for next year, or solidify mate bonds, before heading off over winter. If this is the case then the recently single currawong may be encouraged to leave by other single birds.

Some birds do separate the rearing of fledglings between the pair, such as scrubwrens. Where one parents will feed say 2 young and the other feed the other young. But many also do not, some share the load across both parents or feed the ones who call the loudest. Others, mainly the male feeds the young, others only the female does. It just depends on the species. If one parent dies usually the other parent will attempt to feed all babies, at least in captivity.

 

Benj Whitworth

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