Michael Viney responds to queries and observations on nature
Two years ago at the first frost, a wren took up residence at night in an old swallow's nest and was soon joined by two more. This year there can be a real scramble for the nest with four or five jostling for position.
... Lesley Wishart, Portballintrae, Co Antrim
Wrens will roost in quite large numbers in crevices or old nests in very cold weather.
This year a blackcap has arrived and commandeered both feeders from the regular finches, tits and sparrows. Some hold their ground, but greenfinches have all but disappeared.
Frank Lynn, Carrickmacross, Co Monaghan
Blackcaps aggressively defend their territory against all comers.
While walking along the south beach at Brittas Bay last week I came across 35 mermaids' purses. Is there a particular time when shark family lay their eggs?
Niamh MacGowan, Brittas Bay, Co Wicklow
November to July. These were probably dogfish. The egg cases remain fastened to some object in the sea for five months to a year before the young emerge.