Eye On Nature

An oak tree at Glencairn Abbey, Co Waterford still retains about a quarter of last year's foliage, still green, albeit dry and leathery. In February of last year I would say this was much higher, possibly more than half, and very distinctive. Is this peculiar to individual trees or locations?

Neil Foot, Ballinakill Downs, Waterford

This retention of leaves through the winter occurs regularly in oaks under certain conditions. These are not the usual spring leaves but what is called Lammas growth, as they appear in August. Hot dry spells can cause the trees to lose their spring leaves early, and autumn rains allow the Lammas growth to develop. These new leaves can last well into the winter until frost kills them.

On one garden wall, and attached to a wooden trellis, there's a heap of some two dozen snails. They've all been piled up on each other for several weeks. Are they perhaps holding an ardfheis to elect a new leader?

David Sowby, Knocksinna Crescent, Dublin 18

They are hibernating. If you look closely you will see that they have sealed up the mouth of the shell with a disc of solidified mucus called an epiphragm.

Last year all the frog tadpoles in my well-established garden pond gradually disappeared over a two-week period. I re-stocked and these also disappeared. No fish. There were some insects like water woodlice.

John O'Keeffe, Morehampton Road, Dublin 4

You have great diving beetles in your pond and the larvae are eating the tadpoles.

Eye on Nature is edited by Michael Viney, who welcomes observations sent to him at Thallabawn, Carrowniskey PO, Westport, Co Mayo. e-mail: viney@anu.ie. Observations sent by e-mail should be accompanied by postal address.