A Christchurch researcher is working on a theory that some New Zealand birds such as kiwi effectively have a target pinned on their backs because they never learned to suppress body odours.
Associate Professor Jim Briskie from the University of Canterbury has been awarded $607,702 over three years by the Marsden Fund to study whether odours are playing a role in the decline of native birds.
Behavioural traits, such as nesting on the ground, make birds vulnerable to introduced mammals - such as rats, stoats, cats and possums - but in other countries, birds manage to survive alongside mammals.
Prof Briskie suspects the missing link is smell.
Kiwi have been described as smelling like mushrooms or ammonia; kakapo like musty violin cases - smells that arise from the preening oils which birds use to maintain their feathers.
Birds overseas seem to have less pungent odours, and they suppress the smelly waxes produced by their preen glands while nesting.
New Zealand birds and their preen glands will be studied and compared with related species in Australia that evolved in the presence of mammalian predators.
Prof Briskie will also carry out trials in the field and in laboratories to see whether predators use smell to more easily locate island birds.
NZPA