As quintessential as the ricocheting trills of bellbirds may be in characterising the Australian bush they disrupt the ecological balance, steadily killing eucalyptus trees. Ecologists call this process “dieback”.
Bellbirds live in a colony occupying gum trees, aggressively fending off other birds who try to fly in and feed on the same trees. Very territorial.
The variations of gum trees whether they be blue, red, grey, box etc all have a eucalyptus sap, which bugs called psyllids feed off. These little bugs secrete their own sugary sap, encasing themselves on the leaves in what looks like a mini defence cocoon called a ‘lerp’.
All birds love eating psyllids and their lerps, however the bellbirds are picky and only eat the lerp, leaving the psyllid to live longer and progressively kill gum trees by sucking all their eucalyptus sap. So, the trees end up dieing since the territorial bellbirds won’t let any other birds occupy the same tree.
Once a tree has been drained of its life the birds move on to the next, leaving a trail of ghost gums. I guess the sap is in a sense the trees’ blood isn’t it? And these psyllid insects can be seen to be the vampires of insects.
Dieback affects forests stretching from Melbourne right to Brisbane to the point where particular species of eucalypts are now threatened.
Below are some ghost gums from home, their silhouettes stiff, white, haunting. There were already a few casualties before I went overseas, but since coming home two years on one of the first things I noticed was the now obvious impact caused by bellbirds, which in turn was part of the inspiration to write the poem Australia Bound.
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