Silvereye affliction not pollen
A Lawrence (Otago) resident, Mr Peter Flower, wrote recently about an unusual silvereye on his bird table’s feeding bowl that, on closer inspection, had ‘‘a large pink growth on either side of its head, the one on its left already enveloping the eye’’. Since then he has noticed two more silvereyes with the same affliction, ‘‘although nowhere as advanced as in the original bird’’. He has not seen this previously, and requested that I report his interesting observations here so that others may look out for birds affected similarly.
I suggested initially that the pink discoloration may have been caused by pollen when the birds were feeding. I have seen several silvereyes recently with orange discoloration on their heads caused by reddish pollen from the flowers of flax
(Phormium tenax) which they had been frequenting. Silvereyes at this time of year are often conspicuously discoloured by pollen acquired when obtaining nectar from various flowers. However, Mr Flower wrote again, stating that ‘‘the growths on the birds’ heads are bulbous, quite ugly to see, and in some cases envelop an eye, blinding the birds, while in at least one case the growth can be seen in the mouth, affecting the bird’s ability to fully close its beak’’, indicating that the bird had a tumour.
The silvereye (Zosterops
lateralis) is a small bright yellowgreen bird, grey below, sides reddishbrown, eye ring white, with a sharply pointed bill and a brushtipped tongue, arriving from Australia in the 1850s and now widespread.
Silvereyes are omnivorous, eating invertebrates, fruit and nectar. They eat large quantities of spiders and insects, including very tiny plant bugs such as aphids, psillids and coxids. During winter, when natural food is scarce, silvereyes come readily to birdfeeding tables in household gardens, eating fat, lard, bread crumbs, and sugar water in special feeders with an inverted bottle.
I should be grateful for further reports and photographs of silvereyes affected in this way.