Bulletin

Issue: September 2005

Research in Action

Supersize me - The effects of junk food on seagulls

We throw them food scraps and they swarm in thousands scrounging food from rubbish dumps.

Seagulls love junk food but what effect does it have on their health? PhD student Ms Heidi Auman is trying to answer that question.

She has spent 17 years focusing on human impacts on seabirds and has done research in the US Great Lakes, Midway Island and Heard Island. She is now concentrating on seagulls - more correctly known as Silver Gulls - in two Tasmanian locations.

Although a student at the University of Tasmania, Ms Auman's research supervisor is Dr Catherine Meathrel, head of the Marine Ornithology Group in La Trobe University's Department of Environmental Management and Ecology at the Albury/Wodonga campus.

Ms Auman's PhD research title is: Effects of anthropogenic food sources on the body condition, chemistry and stable-isotopes of blood in Tasmanian Silver Gulls.

'This is commonly called Supersize Me: The Effects of Junk Food on Seagulls,' says Ms Auman who finds that a sense of humour and tolerance for the occasional anti-social habits of seagulls helps her work.

'My aim is to assess the effects of human-sourced food from tips and restaurant handouts on Silver Gulls. It has been widely assumed that an increase in consumption of human-derived food is beneficial and has caused an increase in gull populations, but this has not been tested scientifically.

'I am measuring the health effects of differing diets by comparing several health indicators between remote "natural" (Furneaux Island Group) and urban (Hobart) gull colonies.'

Her research aims are three-fold. The first is to establish baseline reference data on blood chemistry and stable-isotopes for Silver Gulls. Secondly she wants to compare several health parameters between the two populations, and thirdly to measure effects of anthropogenic food on the size, weight and nutrient content of their eggs.

The four procedures she will use are blood biochemistry (cholesterol, triglycerides, lipoproteins, glucose and insulin), stable-isotopes (13C/12C and 15N/14N), body condition indices (physical measurements), and chemical analyses of eggs.

'I tell most people that I study "garbivory" in seagulls,' says Ms Auman who has an MSc from Michigan State University and who chose Dr Meathrel as her research supervisor because of her extensive knowledge of Silver Gulls. She has a world-wide reputation and a generous ability to take students "under her wing" if you will pardon the bird pun.

'Many people have negative reactions to the familiar Silver Gulls, but I view them as a highly adaptable species exploiting the abundant food that we unwittingly, or sometimes purposely, provide. Ultimately, we are responsible for any problems, whether real or perceived, with Silver Gulls.

'Holding wild birds in the hand can be a very gratifying honour, even if they bite, scratch, whitewash or regurgitate on me. In fact, I consider each gull like a Christmas gift, since I can never guess what might be inside.

'The especially interesting ones will sometimes cough up cooked chicken, mince, casserole, peas, onions, carrots, dog food, cat food, spaghetti or chips!'