Michael Viney responds to queries and observations on nature.
Why would two adult swans attack, pin down and bite a hole in a cygnet's neck? Observed at Ballyronan Marina, Lough Neagh, Co Derry. Michael Crozier, Belfast
At this time of year parent swans drive away the cygnets to become independent. Sometimes the young don't want to go and the parents become aggressive, although this expulsion would seem to have been a bit extreme.
We had a vast colony of wasps in our garden all summer. They swarmed on the heart of a large willow tree and on a griselinia hedge underneath. They also seemed to be feeding on some substance on the ground underneath. As well as the wasps there were numerous black flies and butterflies. Liam Roche, Saggart, Co Dublin
The wasps, flies and butterflies were feeding on honeydew produced by aphids on the willow. This is the excess sugar taken by the aphids from the sap of the tree and excreted. You will find that they have done a certain amount of damage to the leaves and shoots of the willow.
Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo; e-mail: viney@anu.ie.
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