Eye On Nature

I have had a tit box on the house wall (north-facing) for about the past 10 years. This year, for the first time, a pair of tits used it for nesting. I have had great fun watching them over the past five or six weeks. Could you let me know if I should clean out the box now that the family has flown, or should I just leave it as it is? I hope it will be used again next year. - Margaret McKenna, Sutton, Dublin

If the birds have flown it is a good idea to clean out the nest box and use a pyrethrum-based parasite killer on it to kill any lodgers. But put a floor of moss into it again as it may rear another brood.

The aquatic snails in our garden pond sometimes swim upside down on the surface. Are they getting some food from the surface film? Could you suggest a suitable nature fish for a pond 11ft x 5ft by one to two feet deep. Stickleback or rudd? - Jim Vale, Clontarf, Dublin, 3

These snails belong to a family called the pulmonates, and they are drawing air into their lungs. On the question of fish, unless you are prepared to feed them, a pond must have a wide enough variety of other wildlife to sup- port them; and if you feed them, the character of the pond changes. Furthermore, if you have fish you are unlikely to have much other wildlife, as even sticklebacks will eat tadpoles, dragonfly larvae, pond snails, aquatic insects and any other animal life it can find. However in a pond well-endowed with wildlife stickle-backs would hardly do much damage.

I recently saw an animal near my house about the size of a big tom cat, with big ears, thick-muscled neck and a reddish/cafe au lait colour. It had a white front and a big tail. I think it must have been a pine marten. I often see foxes, and in May I saw a red squirrel with two young. - Maisie Caswell, Avoca, Co Wicklow.

Yes, it was a pine marten.

A mistle thrush has built a nest on the window ledge of an occupied bedroom in the corner right against the south-west facing window. It seems an odd place for a mistle thrush nest. - Dick Page, Grange Con, Co Wicklow.

Mistle thrushes usually nest high in trees, but they have been known to nest in rock recesses and on the ledges of quarries. You have a marvellous opportunity to observe their activities.

A pair of stonechats have recently taken up residence on our boreen and the male is always around swooping and diving along the boreen in front of me. He seems friendly rather than defensive. Normally they both make their typical "teck" sound, but since the end of April the male precedes his "teck" with a short whistle. - Lorraine Marshall, Kildorrery, Co Cork.

The male stonechat is drawing you away from the nest site. The whistle before the "teck" is an alarm call.

Edited by Michael Viney, who welcomes observations sent to him at Thallabawn, Carrowniskey PO, Westport, Co Mayo. email: viney@anu.ie Observations sent by email should be accompanied by postal address as location is sometimes important to identification or behaviour.