Q: Swallows come annually to my stable loft. They arrive usually around April 17th and depart mid-September. This year they arrived two full weeks early. How do they know, way off in Africa, that Ireland is fit to return to?
Ann Graham, Clondalkin, Dublin 22
A: The swallows of these islands set off from their wintering grounds at a usual time but they often delay on the way here until the weather is suitable and insects are available.
Q: I saw a white mallard on the Grand Canal recently (photograph enclosed). William McEwan, Palmerstown, Dublin 20
A: Albinism can occur in mallards where there is inbreeding. Colour variations are also found among mallard ducks in urban areas where mating with domestic ducks takes place. Eye On Nature had another report of a white mallard duck in April 1989.
