Cats, Rats and Birds……..It’s Dog Eat Dog Out There!

Media Release 13 August 2014

Cats, Rats and Birds……..It’s Dog Eat Dog Out There!

Calling all conservationists! Members of the public who are concerned about the plight of native birds in the Whangarei area are invited to a free evening seminar at NorthTec.

Hosted by NorthTec’s Environmental Sciences department, the seminar will be held on Thursday, 28 August, at 7pm, at the Interactive Learning Centre on the Raumanga campus.

Speakers will focus on the relationship between urban predators and their prey, and what this could mean for the future of native birds in Whangarei.

Environmental Lecturer, Dai Morgan, will discuss the importance of two studies which he carried out, one in the Hamilton area and the other on an island in the Hauraki Gulf. The studies looked at the relationship between urban predators like mice, rats, weasels and cats and their prey, mainly native bird species.

Dai said there was limited research on urban ecosystems, with most studies of native flora and fauna concentrating on areas of bush and open land, rather than city fringe habitats.

The Hamilton study focused on three types of habitat: gullies, public amenity parks, and residential areas. This found that while cats were ubiquitous in all environments, important predators like ship rats and possums were largely limited to gully systems on the outskirts of the city, with little evidence of widespread predator activity in the other areas.

Dai said: “This tells us that pest control is logistically possible in the city of Hamilton. Predators are entering the city via its gullies, so by targeting the gully areas it could be possible to keep predators at low numbers.”

The second study, on a small island, looked at the relationship between what cats eat and what is available to them.

Dai said: “Cats generally choose mammalian prey when they can, because mammals are a far better energy source for them – simply because mammals, like rats, are larger than invertebrates or birds, so provide more calories per kill to the cat.

“This shows that if pest control efforts reduce mammalian predator populations, cats may need to switch to avian prey to satisfy their daily energy requirements.”

With very little research conducted in the Whangarei area, Dai and his colleagues are considering setting up studies that aim to map the distributions of mammalian predators across different habitat types in the city, and investigate whether the impact of feral and domestic cats on native birds intensifies after pest populations are reduced.

Whangarei is an excellent city for such studies as it has numerous green spaces and is bordered on most sides by high-quality bush. Therefore, there is considerable habitat for many native species to use.

Dai believes the planned research will be valuable because it will help wildlife managers identify the most important habitat types to control pests, and enable a better understanding of the potential impact cats could have in areas after the pests are gone.

He said: “Wildlife research in urban areas is often undervalued because cities are regularly viewed as being of low conservation value. However, there are many habitat types within cities that can sustain viable populations of native species, and it is in these areas that many people get their first, or majority of ecological experiences. Therefore, they are very important systems to understand”.

The Environmental Sciences team are interested to hear from other people that work in the areas of conservation and pest control, or who have ideas about protecting Northland’s bird population. For further information, please contact Tanya Cook on 09 470 3857 or email tcook@northtec.ac.nz.

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