Today I was looking for kākāriki karaka nests, and I got solidly distracted. A bird flew across my field of view, it was in deep forest shade, and I realised I wasn't quite sure what it was. I had a look through my 600mm lens and it was immediately clear it was a pīpīwharauroa, with the youthful shape and 'puffiness' of a fledgling. I wondered then if the riroriro foster parents were closeby (see my 2024-10-08 post for more information about the relationship between these species). Within half a minute I saw them too, and they were feeding their giant baby of another species.
The fledgling was making an incessant high-pitched squeaking that sounded absolutely nothing whatsoever like an adult's call. During nesting and the fledgling phase pīpīwharauroa are known to mimic riroriro begging calls, and that's likely what I was hearing. The call involved a chirp every half second like a metronome; it didn't stop unless food (bugs) were being stuffed in its gaping maw. Every few minutes the fledgling would move, usually only 5 metres or so, but perhaps 10 metres and perch again on a branch. The riroriro pair would grab bugs, poke them down the fledgling's gullet and in a flash be gone to find another bug. Probably two or three bugs per minute met their end in that way. When the trio moved I was able to locate them again by listening out for the begging calls (although being high-pitched it was sometimes difficult to locate) and look for bird activity, being three birds on the move made it relatively easy.
The first feeding-action sequence (below), not a great angle for action or light.
Perched, chirping, waiting for food to arrive (below).
The best angle for the action, not bad lighting either. Wish my depth of field was a little better though... Parent arrives with what seems to be a small caterpillar?
Some people have 'difficulty' with brood parasitism. They see it as unfair play or 'bad' behaviour. I don't. The pīpīwharauroa chick did not ask to be born in a riroriro nest. It's as guilty of 'bad' behaviour as any human baby adopted at birth parasitising its adoptive parents. Obviously I mean not guilty at all. Original sin does not exist. No baby of any species (human or bird or any taxon) is born 'bad'. The pīpīwharauroa looks to its riroriro 'parents' for sustenance in the way your cat or dog looks to you when hungry, it knows that's just the way things are supposed to be. Baby ruru or kārearea fed bits of bird to eat and taught that that's what they're supposed to eat are likewise guilty of nothing.
When the fledgling grows up, migrates to the tropics for the winter, then returns to New Zealand to breed, it instinctively lays an egg in a riroriro nest, as it 'knows' that riroriro are supposed to raise pīpīwharauroa young.
It was crystal clear that this giant baby being fed by tiny parents was just that: a giant baby. It was a joy watching the riroriro pair hard at work nurturing the life they'd been entrusted with.
