Fledgling / juvenile kereru
Most details relating to fledgling (dependent on parents for food) and juvenile (independent) kereru are poorly known because there have been few studies of the duration of each stage, the relationships between parents (male versus female) and fledglings, and the acquisition of foraging skills by fledglings. Also, as kereru populations build up in predator-free areas or where predators are under intense control, we may see activities that have not been evident in areas where few nesting attempts are successful (e.g. flocking of juveniles).
Description of fledgling/juvenile:
Eye – brown
Legs and feet – dull brown-pink or purple-brown
Beak – brownish while being fed by parents and lacks feathering at the base giving it an elongated appearance. Once weaned, the feathering at the base develops. Although the exact timing is unknown (about 6 months), the beak gradually turns brown-pink to pale red, with the tip remaining brown longer than the rest.
Plumage – often a few tassels of yellow down adhere to feather tips, especially on head. The demarcation between the white and blue/green feathering on the chest is often ragged, compared to the straight line of adults. The upper edge of the white chest feathers often has a cinnamon wash over them, either as a bar or indistinct blotches, and occasionally as a faint wash over much of the white chest area. The rest of the plumage is generally duller in comparison to that of adults. Tail is short (still growing) when fledgling leaves the nest.
Voice – beg to be fed with squeaks while wing paddling/vibrations, usually one wing at a time.
Fledging:
Nest leaving is a gradual process. It begins with nestlings shuffling off their nests on to branches supporting the nest and then returning to the nest within a few minutes. Gradually the time spent off the nest and distances moved from it increases such that the nestling only returns to the nest when a parent approaches to feed it or to roost on the nest at night. This fledging process lasted about 5 days in the parea, and is not known for the kereru.
Having left the nest, fledglings initially spend much time perched in one tree waiting to be fed by their parents. Gradually their strength, fitness and flight abilities improve to the point where they are able to accompany a foraging parent and learn to feed themselves.
Independence:
There is quite a bit of variation in the literature as to the duration of the fledgling stage from nest leaving to independence; at least 1 week to about 6 weeks. In the parea it was found to be at least 3 weeks and up to 5. Much of this variability may depend on the local food supply and whether the parents re-nest promptly. If fruit is readily available and the parents re-nest then the impression is that fledglings may be fed for just a couple of weeks before being ignored. In contrast, independent juveniles have been seen accompanying their parents for several months after breeding has been completed.
I have not seen or read about juveniles gathering and moving about together as an age-group flock. However, this may have been a function of poor nesting success such that there were few occasions when several juveniles were present in an area to form such a flock.
