UC students discover native birds thriving on Ilam campus

A chance discovery and a new survey by University of Canterbury students have shown that both the range and abundance of native bird species have increased at the university’s Ilam campus almost 500 per cent in the last 26 years.

As part of a lab exercise for their Biology course, a group of second-year UC Science students created a bird atlas of the UC campus in Ilam and compared it to a similar atlas from 1990, created by a BSc student in Zoology.

The results of the recent survey indicate that in the last 26 years, all native species increased in range and abundance with an increase of almost 500% in the total number of native birds observed. For example, only a single grey warbler was observed in 1990 but this increased to 19 individuals in the new survey.

UC School of Biological Sciences academic Professor Jim Briskie says it is likely that the changes are due to the increased plantings on campus of native trees favoured by native birds, and decreased open space, which is the habitat favoured by many introduced species.

The idea for the new survey was sparked after a student project report from 1990 was discovered during the School of Biological Sciences’ move into new facilities. A generation before, an undergraduate Zoology student, Krystyna Kavanagh (nee Dodunski), conducted a detailed survey of bird diversity across campus, mapping the distribution of each species and estimating the number of birds.

“I immediately thought it would be worth following up this study with a new survey to see what has changed but didn't have the time to do it entirely myself,” Professor Briskie says.

“We needed to create some new lab assignments for our New Zealand Biodiversity and Biosecurity course (BIOL 273), and it seemed like the perfect opportunity to resurvey the campus to find out what has happened to the bird fauna in the 26 years that have passed from the original 1990 survey.

“The survey was also an excellent way of giving the students hands-on practical experience in conducting a biological survey, including having them learn to identify all potential species of birds by both sight and sound.”

Professor Briskie says it is likely that the changes are a product of the increased plantings on campus of native trees favoured by native birds, and decreased open space, which is the habitat favoured by many introduced species.

One species, the bellbird/korimako, is now in the early stages of colonising campus, he says. And fantail/pīwakawaka, grey warbler/riroriro and silvereye/tauhou (or wax-eye) have all become significantly more abundant on the UC campus in Ilam. The greatest diversity of native birds occurred along the campus waterways.

“I had heard bellbirds singing on campus over the last few years, so I knew they were in the process of colonising campus, and I had also seen over the last 20 years that I have been lecturing at UC, the increasing planting and maturation of native vegetation, especially along the rivers that run through campus. This has created new habitat for native birds, which do best in native forest habitats.

“On the other hand, the increasing density of buildings on campus and in the surrounding area has probably had a negative effect on bird populations overall, reducing the overall area suitable for any native birds. This is making the green spaces of campus important as ‘islands’ of habitat in an otherwise increasingly unsuitable urban environment.”

As well as the grey warbler, fantail, silvereye and bellbird, the welcome swallow and grey duck were also recorded, he says.

“Maintaining and expanding native plantings at UC could also help to further increase the range of native birds, like the native pigeon or kererū,” Professor Briskie says.

Given the dependence of bellbirds on flowering and fruiting trees, Professor Briskie suggests it is worth considering plantings that provide this resource, and to ensure that the current small population of bellbirds does not disappear.

“Restoring species that formerly occurred in the Christchurch area but are now locally extinct could be a long-term goal for the management of the campus green spaces.”

Professor Briskie plans to run the survey annually as part of the BIOL 273 labs.

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