Puteketeke - Australasian crested grebe - Podiceps cristatus australis
The grebes I have been following now have eggs. It is difficult to see into the nest but they have at least two eggs on which they're taking turns sitting.
Interestingly the other grebes in the area took a great deal of interest in my careful approach (wading) to the nest from the water side, staying extremely low in the water, to try to reduce my visual impact and their alarm. These other birds (which feature in most of these pictures) approached quite close and seemed to be trying to distract/lure me away from the nest area while the parents themselves stayed on and near the nest. I have not read any accounts of grebes behaving in such a defensive social manner before so I don't know if this is unusual or commonly observed behaviour.
After nearly two hours in the water moving very slowly I was finally able to get close enough to the hidden nest to get a few "through the branches" shots but was unwilling to push the birds by attempting to get closer as I did not want to run the risk of them abandoning the nest.
In New Zealand these birds breed only in the South Island in lowland lakes west of the Southern Alps and on subalpine and alpine lakes within and east of the main ranges with the greatest occurrence in Canterbury. They are a fully protected and threatened native, having disappeared from much of their former range, although the Canterbury population seems reasonably stable. But their low numbers and relatively few breeding places leave them very vulnerable to human interference and habitat changes.
Their breeding lakes include the Ashburton Lakes in Canterbury where my family own a traditional kiwi bach (basic holiday cottage) and so these birds have been part of my family recreational culture and surroundings for many years. Those in these pictures, however, were photographed on Lake Forsyth near Christchurch city.