OLD KILPATRICK, SCOTLAND — AFTER they bought their house on the end of a row built in the 1950s, Daniel and Catherine McDonald discovered there were bats in the roof.
They found out later the bats were pipistrelles - minute creatures 1-1/2 inches long with a wingspan of 8 inches, weighing half an ounce. They are the commonest of the mere 14 species of bat inhabiting Britain. One or two had found their way into the rooms.
But the bats didn't put the McDonalds off. They moved in anyway. By this summer, however, the bats were becoming noisy on summer nights as Mr. McDonald tried to use his computer. ``They chatter,'' he says, ``that's the only way to describe it. Chatter.''
The McDonalds decided it was time they learned some things about their bats. Were these tiny flying mammals endangering the house's structure or causing any other hazards? Should the McDonalds prevent them from coming back next summer by blocking the holes through which they were apparently entering the roof?
Alec Walker, the janitor at Auchentoshan and Mount Blow Schools nearby, had become concerned about some bats that had taken up residence above the ceiling of the girls' changing room in the pool house - possibly one of the warmest places in Scotland.
Bats are on the edge of their range here, in this cool climate. Only 8 species exist, and they look for warm sites to give birth and milk-feed their young. Mr. Walker wondered if they were a health hazard.
Walker phoned the environmental health people, who advised him to do nothing until he had spoken to Scottish Natural Heritage (SNH), a quasi-government body established by Parliament and concerned with the conservation of wildlife, habitat, and landscape.
So Dorothy Simpson of SNH visited the McDonalds and afterward dropped in on Alec Walker. ``Dorothy was in her element,'' says Mr. McDonald, ``in a boiler-suit rummaging about under the eaves trying to see the bats.''
She confirmed for the McDonalds and Mr. Walker that all bats are legally protected in Britain as ``endangered, threatened, or vulnerable.'' It is against the law to disturb their roosts. One species, the mouse-eared bat, was declared extinct in 1991.
Ms. Simpson's main role is to demythologize bats. Mr. McDonald now tells people that ``the expression `bats in the belfry' is wrong because bats don't like cold, drafty places.'' He believes some people refuse to admit they have bats in their roof space ``because they think of them as vermin. They aren't.'' They do not damage buildings. Their droppings (unless they get wet) are dry and fall to dust. They do not smell. There are no cases of bats in Britain being suspected of carrying disease. And they actually do some good keeping the local insect population down. Ms. McDonald says she notices fewer spiders and flies in this house than in the couple's previous home.
Do the McDonalds plan to block up their roof this winter, once the bats have left for hibernation in cooler conditions, to stop them returning next summer?
``No,'' Daniel says, ``it's live-and-let-live. We have blocked up any access into the rest of the house - which they don't want either - and as long as they stay in the roof, we are happy.''
Alec Walker at the school swimming pool is just as content as the McDonalds. Simpson advised taping over various openings inside the changing room to make sure the bats are confined to the roof space.
A few days after the visit, Walker phoned Simpson to say he had decided to remove all the tape he had put up because he was worried he might have disturbed his bats.