Matthew Brears, of Lake Tarawera, asks :-
Tuis appear to vanish for two months during the winter. Where do they go to?
Hugh Robertson, an ecologist with the Department of Conservation, responded.
In the Rotorua district, Keith Owen reported that tui are known to move to specific sources of nectar such as kowhai and rhododendon - the former is around some of the lake shores (especially Rotorua and Rotoiti) and in the city itself, and I guess rhododendons are largely in the city. These two species that Keith named probably flower in spring rather than winter, and so my guess, based on what I found in Hawkes Bay, is that in the winter many tui will be feeding on flowering gums.
In Hawkes Bay, I studied a population of tui breeding in a 60ha bush reserve on the Maraetotara Plateau towards the coast near Waimarama. After summer breeding, and feeding on fruits of various shrubs and podocarp trees in the autumn, over 90 per cent of the colour-banded birds ended up feeding on flowering gums, 10-20 km away, through the winter. Most travelled 20km to Havelock North for the winter - accomplishing the trip in a single day, and probably actually in an hour - and then spent the winter in town. Birds regularly used the same patch of gums or even a single tree, day after day, and year after year. I have heard of colour-banded Tui travelling a lot further than 20 km to find good reliable food sources (e.g from Dunedin to Oamaru).
In late winter the birds returned to Mohi Bush, but commuted 5km daily to feed on flowering kowhai, until Fuchsia started flowering in Mohi Bush.