In A Nutshell
Unlike the majority of birds from other continents, native New Zealand birds have such pungent body odor that it tips off predators to the birds’ presence. Conservationists may have to place deodorant or odor-eaters in these birds’ nests to prevent their extinction. But no one’s sure if the stench is vital to their existence in another way.
The Whole Bushel
New Zealand is home to many different types of birds, but the native ones smell really bad. Some of the worst are two flightless species: kiwis, which give off a strong odor of ammonia or mushrooms, and kakapo parrots, which stink like a musty violin case. Scientists are concerned that many species will become extinct if they aren’t protected. Some of the birds are especially vulnerable because they’re flightless.
“We do know that it’s easy for muzzled dogs to find kakapo and kiwi by their smell, so I suspect that predators like rats or feral cats might be able to easily find native birds also,” said biologist Jim Briskie of Canterbury University in Christchurch, New Zealand.
For many birds, their body odors come from the gland that makes preening wax to keep their feathers healthy. On other continents such as the Americas and Europe, a bird’s body will change the composition of this wax during mating season to lessen its odor in an effort to protect the bird’s nest from predators. Even in New Zealand, European birds do this.
The reason for this difference is that American and European birds evolved with mammals in their territories, but native New Zealand birds did not. About 80 million years ago, New Zealand’s land mass broke off from Australia. But no mammals came with it, so native New Zealand birds didn’t have to develop a protective mechanism to fend off that type of predator.
The problem occurred when humans began to introduce nonnative mammals like rats, cats, and stoats (which look like weasels). The strong smell of these birds made them easy targets for their new predators.
There are a number of possible solutions being studied by biologists and conservationists. One is to place deodorant or odor-eaters in these birds’ nests to prevent their extinction. But no one’s sure if the stench is vital to their existence in another way, perhaps as a communication method with offspring or mates. Scientists could also use the birds’ odors as a bait to trap their predators.
The Department of Conservation manages all conservation of New Zealand’s waters and land. They focus on controlling the introduced predators as a way to protect native species. Their current methods vary with the type of problem and range from labor-intensive traps and bait stations on the ground to less expensive aerial drops of biodegradable 1080 poison where ground access is difficult. (This poison uses 1080 as the active ingredient, which is found naturally in certain plants in Africa, South America, and Australia.) Along with some private citizens, the Department of Conservation has achieved some success in creating a pest-free sanctuary for native New Zealand species on some islands, including Great Mercury Island (aka Ahuahu), Little Barrier (aka Hauturu), Tiritiri Matangi, Rangitoto, Motuihe, and Motutapu in the Hauraki Gulf Marine Park.
Show Me The Proof
National Geographic: BO Attracting Predators to Birds
New Zealand Department for Conservation: Work begins on making Great Mercury/Ahuahu a pest free sanctuary for native wildlife, Methods of pest control, 1080 poison for pest control