Michael Viney responds to queries and observations on nature.
We watched through binoculars a hen harrier quartering the ground over the fields between us and the sea. It flew down to the sand dunes, glided low around them and dived to the ground. It must have found something to eat. We were sole witnesses to this and I wondered how many unusual or rare birds appear along this stretch of the coast and are never observed.
Bruce and Jean Vaughan, Thallabawn, Co Mayo
We have a number of bats in the roof space of our house. During the winter months large numbers of flies have been hibernating in the cracks of the wooden windows. My wife's theory is that dead bats are decomposing in the roof space and attracting the flies, and suggests blocking the entrance hole. I am aware they are a protected species and it is illegal to interfere with their habitat.
Terry Lawlor, Lismore, Co Waterford
Bats leave for winter quarters after breeding and are unlikely to die in the roof space. Cluster flies come into houses in large numbers in winter and hibernate in attics and crevices.
• Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo; e-mail: viney@anu.ie (include a postal address)