Banded whio found on the Tongariro river
Date: 29 July 2008
Reports of a banded whio (blue duck) on the Tongariro River has excited local Department of Conservation biodiversity rangers, especially as the bird is thought to have come from the upper Whanganui/Whakapapa or Mangatepopo Rivers.
On July 20 a local couple, Janet Hart and her husband, provided DOC with exciting information when they emailed photos of three whio they spotted by the Breakfast Pool. One of the birds had a coloured band on its leg.
Exciting new inhabitant on the
Tongariro river
DOC staff from Central North Island Blue Duck Programme, based at Ruapehu, confirmed the banded bird is a two-year-old year old breeding male, which had dispersed from the Upper Whanganui/Whakapapa or Mangatepopo Rivers.
"This is a very good sign for the survival of whio on the Tongariro River," says Lucy Roberts a Biodiversity Ranger in Turangi. "The benefit of a whio flying in from the Ruapehu rivers is that the bird brings different genes and will increase the genetic diversity of birds on the Tongariro River."
In October last year a family of seven whio were sighted on the Tongariro River and DOC asked members of the public to report any sightings of the threatened bird to its staff in Turangi.
"We had a great response to this request with more than 40 sightings reported throughout the breeding season," says Lucy Roberts a biodiversity ranger based in Turangi. "The sightings are entered into a database which we use to map the distribution of whio in this area."
"This enabled us to follow the progress of the whio family, (two adults and seven chicks) on the Tongariro River," she says.
Generally, whio territories are approximately 1.5 km in length but the Tongariro reports showed that this family used 9km of the Tongariro River, from Fence Pool down to the Turangi State highway One bridge.
As well as adding to the gene pool, the Ruapehu whio show that the birds don't always do what the text books says they should. When whio disperse from their natal territory they mostly go downstream or over the whole catchment. Other birds banded in the same year on the Upper Whanganui/Whakapapa or Mangatepopo Rivers have been recorded dispersing 10km upstream from their natal territories.
"These particular birds obviously did not read "The guide to dispersal of whio" and flew upstream and even to another catchment'" says Lucy Roberts.
One reason for the unusual dispersal pattern could be that for the Central North Island Blue Duck Programme, this season has been the most productive and successful yet. Chick production was almost double any previous year. As a result more chicks fledged, there was less local territory for new birds to inhabit and this increases the need for the young birds to disperse. Population dispersal of young male birds is a good indicator that the Ruapehu blue duck programme is succeeding in improving the future of whio.
Predators and loss of habitat and water quality are the main threats to this endangered bird.