The impacts of kangaroo grazing on birds – have your say

Superb Blue Fairy-wrens need dense bushes to shelter and nest in. Credit: John Gitsham

The impacts of high numbers of kangaroos in our conservation parks and native bush was recently highlighted in the media by Associate Professor David Paton, past President of Birds SA. David has documented the decline of habitat in parks like Sandy Creek over the past few decades. The visible growth of plants shown within fenced areas that keep grazing animals out clearly demonstrate the intensity of grazing occurring. Tom Hunt, one of David’s PhD students, who also happens to be a great birder, photographer and naturalist in general, also provided a detailed explanation of the kangaroo grazing issue in a blog on Facebook, which is well worth reading.Certainly my own observations support David’s view, which is also shared by many ecologists that I talk to. Just the other morning I was out in the Mt Lofty Ranges undertaking annual spring bird surveys. I did a survey in Charleston Conservation Park, a small but highly important woodland remnant. The appearance of the park was quite astounding – it looks more like a manicured parkland than a conservation bushland.Kangaroos scattered in all directions as I walked to and from the bird survey site. This was typical of many visits I have made to the park over the past eight years. Although I didn’t see any other grazing animals, you could also reasonably expect some rabbits and hares, and maybe some deer to be in the park, but there are no sheep or goats, or cattle. There is little doubt that kangaroos were over-grazing the park.

On my way back to the car I observed two small fenced areas, erected by David to allow him to assess the level of plant regrowth. I’ve seen plenty of these over the years, but the regeneration within these areas even surprised me. You expect to see greater plant growth, more grasses and a few seedlings from trees like the sheoak, but there was also dense cover of regrowing shrubs, such as tea-trees, that I didn’t realise were missing from the rest of the park. No doubt a closer inspection would reveal a great diversity of small shrubs regrowing behind the fence, many important for birds.

Brown Thornbills make use of dense bushes for shelter, nesting and foraging. Photo: Tom JHunt

It’s easy to appreciate that the high levels of grazing from kangaroos is changing the nature of the park in a negative way. Personally I am not interested in trying to restore areas like this to “pre-European” as I don’t believe this is a logical objective. However, to secure the future of parks like this, – to ensure that they are functioning, and also providing food and shelter for the birds we all love, means that the plants need to be able to grow, reproduce and replace themselves through germination and establishment of seedlings. For many birds the flowers and associated nectar are critical. Clearly in places such as Charleston Conservation Park this is not occurring, and the value of the habitat can only continue to decline if the plants can’t reproduce.

Of course, we all love kangaroos, and the wider community can struggle to understand the complex nature of these types of ecological issues. However, in terms of solving problems like this, I have come to see that the ecological science is readily straight forward compared to the social side of these issues. It is actually the social conditions that enable ecosystem management, ideally through the implementation of adaptive management. Ultimately, solving these problems requires involvement of diversity of people, with a diversity of views, with a process that is transparent and legitimate. Only then can we expect to have a range of management options on the table.

It is timely that as part of an undergraduate internship with the University of Adelaide, a pilot survey is being conducted with the aims of investigating the social values held by the South Australian community in relation to kangaroos and the management of kangaroo populations. Currently, there is a gap in knowledge between social values and kangaroo management, and this survey is designed to:

  • measure preserved knowledge on kangaroo populations
  • evaluate where population control is determined to be necessary 
  • determine attitudes around the harvesting of kangaroos as a resource

Information supplied by survey applicants will be anonymously provided to DEWNR to assist in decisions around management of Kangaroos in South Australia. Please take the time to complete the survey where you can express your own views. The survey can be can be accessed at here.

 By Jody Gates
Note: the views expressed here are those of the author, however, Birds SA supports controlled ethical kangaroo management where unsustainable numbers are degrading native bushland and therefore impacting on birds -John Gitsham, President.