Well-meaning residents of New Zealand’s capital may be killing the city's endangered birds with kindness. It turns out that the chicks of the kākā birds that live in Wellington are failing to survive because locals are feeding the parents the wrong type of food.
An urban ecology team for Wellington have been keeping track of the birds that live in the parks and reserves surrounding the city, and found that last year 80 percent of the chicks failed to make it to adulthood. Investigating this devastating survival rate, they found that residents feeding the adults food such as nuts, seeds, and bread, which then go on to regurgitate it for their offspring, is causing the chicks to develop metabolic bone disease.
This causes problems with the strength of the bones in developing birds. Some kākā have been found to grow up with deformed limbs and bone abnormalities, including beaks that struggle to close. It is thought that even if the chicks do survive to adulthood, their bones are so weak that the slightest of knocks can cause them to shatter.
“Last year we did autopsies on kaka chicks we found dead and in a number of them we found nearly every bone in their body had fractured because of the disease,” the council’s urban ecology team leader Myfanwy Emeny told the Guardian. “The saddest thing about this condition is it is a preventable disease. People just love the birds, they are trying to do the right thing by feeding the parents but it is resulting in this horrible condition in the chicks.”
The birds are a type of large parrot that are native to the islands, but have been decimated in numbers in recent times. Usually found living in the forests, the kākā have declined greatly due to habitat loss, invasive predators, and competition with wasps and bees. The introduced stoats are known to predate on nesting females as they incubate their eggs, while breeding birds are being outcompeted by wasps in the collection of a vital food source: honeydew.
This is not the only example of people trying to do good by feeding wild birds but instead inadvertently harming them. Angel wing is a condition that can afflict ducks and geese that are fed a diet too high in bread, causing the wings of developing chicks to grow to such an extent that they are not able to fly.
The urban ecology team recommend that rather than feeding the kākā nuts and bread, residents should instead plant native trees and shrubs, in addition to providing drinking water. They say that there is plenty of natural food in the surrounding parks to keep the birds sustained.