St Brigid's Day is past (did you see many of her crosses around, or any?) and we're surely coming into mating and nesting time for the birds. And those children who notice such things will be asking: "Daddy, why do blackbirds always build the same sort of nests and blue tits and other birds make quite different homes for themselves? And, Daddy, why do they continue every year to follow their own kind of home? Blackbirds never build like tits..." and so on. You can put them off by referring to instinct, something automatically placed in their brains from time immemorial, and maybe quieten them. You can't tell them that the parent birds teach the young how to build, for the young are usually pushed off as soon as they can make their own way. So some birds go on making cup-shaped nests and others domed nests, and yet others scrape a hole in the ground and take their chances. And it's probably the sheer ingenuity of the threading and cementing with mud of the grasses that makes such a mockery of us humans talking derisively of bird-brained people, said a friend.
And the sharpness of bird perception was the subject of a letter written many years ago and incorporated in a volume called Harvesting The Field, referring to the English magazine. A man wrote to say that he was sure birds could tell in advance when a tree was going into decay and thus was dangerous. Two large elm trees, he wrote, had had nests in their tops for at least 10 years. Then the birds ceased to build in them. Five years later these trees made no fresh foliage and showed dead twigs at the top. When cut down they were found to be rotten and dangerous. Another elm which had plenty of foliage never had birds' nests, although birds built in surrounding trees. "This particular tree was blown down last month and was found to be completely rotted through at the base." Another elm, this correspondent writes, has had no nests in it for about 10 years, although earlier they did build in it. "Last week I decided to examine this tree and cut the top portion. It was rotten from the centre to within three inches of the bark and yet has thick foliage and shows no sign of decay from the outside." Perhaps, he writes, the birds can recognise a smell of death in trees.
And another correspondent on the same topic concludes: "My experience of birds has taught me that they have far more practical common sense than most people believe."