Silvereyes feeding on lerp

On a recent BirdLife East Gippsland Monday morning outing to Log Crossing in the Colquhoun Forest near Lakes Entrance a few of us came upon about six Silvereyes feeding on the common reed (Phragmities Australis) growing beside Mississippi Creek. The birds were very intent on gleaning something from the underside of the large leaves. 

Silvereyes have a broad diet including fruit, seeds, insects and nectar. We were intrigued to know exactly what these birds were feeding on which was not obvious as the birds were foraging on the underside of the leaves which were not visible to us.

After taking some photos we checked the underside of the Phragmities leaves and found large amounts of the telltale white sugary coating commonly called lerp (1). Under the coating we found small – not much larger than a pin head – green psyllid bugs (or their larvae?) which make the starchy protective coating. We could not tell if the Silvereyes were eating the sugar rich coating, the larvae or both. I suspect both, given both fit within the known diet of Silvereyes – a rich food source containing proteins and sugar.

Checking the photos later at home on my laptop I could see fragments of the white sugary coating on the bird’s bills and in one case, its back. Also one photo captured some of the lerp on the leaves. An indication of the value of this food source may have been displayed by an altercation between two birds over feeding access to a reed stem – see photo below.

Please click on photos to enlarge.

Note lerp on the tip of bill and the back in the next photo.

The white lerp is visible in the following photo. There were larger pieces forming protective coatings over psyllid bugs on the underside of many of the leaves.

The bird in the following photo is picking lerp off the underside of a leaf – a fragment of lerp is visible on its back.

A feeding area dispute.

There are about nine subspecies of Silvereye across their range in Australia. The birds we found were Zosterops lateralis lateralis (note the rich brown flanks), the Tasmanian sub species, many of which make seasonal migrations across Bass Strait to winter on the mainland. 

Note (1) The word lerp comes from the Wemba Wemba lerep. Lerps are a traditional food source for Indigenous people.