Why the daily bread is not good for birds
Most of us love to feed the birds but giving them bread may not be the best way to help our avian friends, writes Jo McCarroll.
We are a nation of bird feeders. A study of six New Zealand cities a couple of years ago found around half of us regularly feed our feathered friends.
The research, by scientists in New Zealand and Australia, sent a questionnaire to 3000 households across Whangarei, Auckland, Wellington, Nelson, Dunedin and Invercargill.
The study found that 46.6 per cent of the households surveyed regularly fed birds. The majority of those feeding birds were providing bread (88.1 per cent); while fewer people provided fruit (40.8 per cent) or seed (39.4 per cent). Despite many New Zealand birds being nectarivores, or naturally nectar-eating, only 17 per cent of the households that fed birds put out sugar water.
‘‘Most of the people we questioned enjoyed seeing birds in their garden and interacting with them,’’ said urban ecologist Josie Galbraith, who was one of the authors of the study. ‘‘And most of them thought that providing birds with any kind of food was helping them, while not many of them identified any possible disadvantages of feeding birds.’’
But effectively, Galbraith says, feeding wild birds is a massive supplementary feeding experiment. ‘‘We have so little information on what outcomes feeding has for birds, particularly in our urban areas where most of the feeding takes place.’’
To help determine some of those outcomes, Galbraith was part of a team which conducted a second study over 18 months at 23 residential properties across Auckland. Half of the households fed the birds every day, putting out four or five slices of bread and one metric cup of birdseed each morning; the second half put out no supplementary food at all.
The households that fed the birds reported a dramatic increase in birds on their property within weeks of starting to put out food. Closer observation, however, found the newcomers were more likely to be introduced birds rather than natives. Of the four native birds commonly seen in Auckland gardens – tui, fantail, silvereyes and grey warblers – the first three were apparent in similar numbers at feeding and nonfeeding gardens. There was a considerably more dramatic – and negative – impact however on the gray warbler. ‘‘We saw the grey warbler decrease by more than 50 per cent once the feeding regime had started.’’
The bad news doesn’t end there. Offering bread and seed in your garden not only negatively affects native biodiversity, a large number of birds regularly crowded into one area increases the likelihood of avian diseases being transmitted between them, says Galbraith.
If you really want to bring the birds into your garden, especially if you want to support native species, the best thing you can do is plant with those birds in mind, Galbraith says. Grow native trees and shrubs that provide nectar, seeds or berries, and choose plants with different flowering and fruiting times so food is available all year round.
Feeding does not help grey warbler numbers, the study has found.