Most bats eat insects and are called insectivores. Bats like to eat beetles, moths, mosquitoes, and more. And they eat a lot of insects. One little brown bat can eat up to 500 mosquito-sized insects in an hour! But New Zealand’s bats are in serious decline.
The Department of Conservation website says “There are three species: the long-tailed bat, the lesser short-tailed bat, and greater short-tailed bat. The greater short-tailed bat is thought to be extinct. The long-tailed bat is classed as ‘nationally critical’, while the short-tailed bat subspecies range from ‘nationally vulnerable’ to ‘recovering’. They are in danger of extinction in the medium term if nothing is done to reverse their population declines. These species are a high priority for conservation.”
The Department of Conservation uses 1080 over large areas of public lands supposedly to kill animals which the department misguidedly rates as “pests”. But 1080 was originally developed as an insecticide in the 1920s. Wikipedia says the poison “is highly toxic to mammals and insects.”
A Marlborough resident John Allen, an ancestor of one of New Zealand’s earliest tribes, the Waitaha people, believes a major reason behind the disappearance of bats is the lack of food. He has noted the disappearance of insects which leaves bats with no food source. He blames insecticides.
“It’s absolutely incredible. There are no insects flying around at night. now. You can leave your windows and doors open with the lights on and nothing will fly in,” he told the Marlborough Express newspaper in 2018.
He reckoned there was a 75% reduction in insects. The area at Grovetown where he lives is surrounded by vineyards.
Laurie Collins of the Sporting Hunters Outdoors Trust said there was a “cocktail of chemicals” – that included insecticides – being used on the New Zealand environment. On the lowlands, insecticides such as diazinon were widely used.
Diazinon is an insecticide that belongs to a group of chemicals known as organophosphates. Diazinon is used in agriculture to control insects such as grass grub on pasture, and others on fruit, vegetable and field crops. Diazinon has been used in the United States since 1956.
Realisation of its lethal nature led to the USA cancellation of residential uses in 2004, diazinon was used for household insects, lawn and garden insect control, and to control insects on pets.
Diazinon was very highly toxic to birds, bees and most other insects. Studies show that diazinon was also toxic to fish and amphibians. One authority described it as “highly lethal” to aquatic life.
However in wilderness areas DOC’s and OSPRI’s large scale use of the insecticide 1080 were logically destructive of insects he said.
“In essence, eliminate bat’s food and you eliminate bats,” said Laurie Collins. “Any 5th form school biology pupil could tell you that.”