Tāmaki Innovation Campus

It makes us happy, but what’s it doing to the birds?

Josie Galbraith with a little wax eye bird.
Josie Galbraith says she is very interested in what makes urban areas habitable for birds, so we can apply this to urban conservation and encourage more biodiversity in our cities.

We’ve all done it; thrown some bread scraps to the birds in the garden, but just what are we doing to the birds and their environment when we do?

The perplexing question is the subject of Josie Galbraith’s PhD research in the School of Biological Sciences. Her study looks at the serious potential implications of both supplying a copious food source for wild birds and encouraging congregation of these birds at a focal point to feed.

It also looks at the effects of enhancing populations of introduced birds and increasing the spread of avian disease.

New Zealanders are unique in their bird feeding habits, with our US and UK counterparts more usually feeding seed or specialist bird food. The practice of feeding wild birds is a widespread phenomenon, but Josie believes there has been little consideration of both human and ecological dimensions of the impacts.

While birds are a dominant feature of urban ecosystems with many species surviving in urban centres throughout the world, few studies have focused on avifaunal assemblages in urban environments, particularly in the Southern Hemisphere.

“The practice of bird feeding is becoming increasingly common, and given the lack of attention by the scientific community, appears to be perceived as a harmless human activity,” she says.

Josie questions why we do it, and just how harmless is it? The question is slowly being answered through two main strands of her project: quantifying the practice of bird feeding in New Zealand through a nationwide survey to 3,000 households; and investigating the effects of common feeding practices by establishing and monitoring a series of experimental feeding stations in urban Auckland.

“The experimental feeding stations were active for 18 months, with householders providing a prescribed amount of food on a daily basis. This experimental feeding regime allowed me to examine whether feeding causes changes in local avian community structure. Simultaneously, I also collected baseline information on which species are utilising supplementary food sources, their visitation frequency, interactions at feeders, and effects on body condition, parasite load and disease transmission.”

Outcomes so far estimate that around 46.6% of households feed birds. Increased age and dog ownership are strongly associated with participation, and bread is most commonly provided. The principal potential risk identified is that introduced birds are likely to be the main consumers of supplementary food sources in New Zealand, which may have follow-on effects for avian community composition.

Disease transmission risks were also identified, with poor hygiene practices reported by many respondents. However, the social benefits to humans of feeding birds is strongly reflected in the motivations of the respondents. Over half feed birds because it brings them pleasure.

As urbanisation increases, opportunities for connecting with nature decrease. Consequently, experiences such as bird feeding, that increase the interaction between people and wildlife, could be a powerful tool for fostering environmental awareness and guardianship.

Josie’s study highlights that humans may inadvertently make harmful choices for wildlife, without realising the ecological consequences. She recommends developing appropriate guidelines to minimise risks.

Josie says there is much more work to be done in this area, with this project barely scratching the surface. In particular, more studies into food types being fed, disease transmission, and how far birds will go to access these free food sources. 

She looks to the future with confidence, acknowledging there is an excellent group of urban ecologists at Tāmaki Innovation Campus to continue research into urban bird populations and how humans affect them.