Boaties are being reminded to leave their dogs at home if they intend visiting Lake Wanaka's islands.
Department of Conservation ranger Flo Gaud said dogs were believed to be responsible for the death of one of a breeding pair of buff weka on Te Peka Karara Island, or Stevensons Island, late last month.
''A witness reported that a black Labrador was sighted on the island at the time,'' Ms Gaud said recently.
Once plentiful in the South Island, the light-coloured buff weka is now found only on Chatham and Pitt Islands - except for populations introduced to Te Peka Karara and Mou Waho Islands in Lake Wanaka, and Pigeon and Pig Islands in Lake Wakatipu.
Te Peka Karara has five or six breeding pairs.
Ms Gaud said there had also been two reports from the public of dogs being illegally on Mou Waho this summer.
Signs warning dog owners it is an offence to take dogs to the islands are in place at several points on the islands and at lakeside boat launching areas.
Ms Gaud said the disturbance of wildlife on the islands was disappointing and frustrating.
''It is very sad to see this abuse of the rules on the island.
''Ignorance is not an excuse.
''It is important dog owners realise the consequences to endangered wildlife of not having their dogs under control, and that they can be prosecuted.''
The Conservation Act specifies a fine of up to $10,000 for dogs injuring or killing protected wildlife.
Te Peka Karara is a 65ha Doc scenic reserve on the eastern side of the lake, 11km from Wanaka.
It has previously been affected by fires, and possums, rats, mice, rabbits, stoats and ferrets have been found there.
However, it has a number of native plant species and also populations of white-faced herons, black shags, bellbirds, brown creepers, fantails, wood pigeons, tomtits, grey warblers and pied tits.
Community groups undertook the planting of rata in a project called Project Crimson.
Ms Gaud said Doc was concerned also about the risk of fire on the islands.
Eco Wanaka Adventures owner Chris Riley, who takes trips to Mou Waho, said the public was getting the message about dogs and there were fewer going to the island.
Mr Riley said there were more than 150 buff weka on the island but they were ''ecologically naive'' and would even walk up to a dog that was tied up.
''The signs are there, and people who ignore the signs, be warned.
''I'll take a photo of them and I will send it to Doc.''
