Propeller sounds and bird talk
HAVE you ever considered the fascinating ability of songbirds trilling their morning choruses in dialects appropriate to their native areas?
They do. It was news to me. Can you imagine, for example, Cavan warblers having a distinctive handle on a few bars that sets them apart from a feathered Kerryman or a warbler from Mayo?
And just how can you tell? Not easily, and certainly not without detailed study of carefully recorded sounds.
One man opened a door on this world with his adaptation of a device invented to help win the battle of the Atlantic in the Second World War, the sonic spectrograph, which recorded and made graphs of the sounds of the propellers of enemy ships. Dr Peter Marler, an English-born scientist and academic, who died last week aged 86 in California, was one of the first ethologists to use this method to produce graphic snapshots of birdsong — inked streaks on paper like an electrocardiogram showing the wave-frequency, modulation and pitch of various bird calls and songs.
He showed that birds not only learned their songs but also in a dialect peculiar to the region in which they were born. “Dialects are so well marked that if you really know your white-crowned sparrows you will know where you are in California”, he was quoted as saying. Dr Marler was one of the first scientists to consider that some animals, like humans, were capable of learning and transmitting their knowledge to other members of their species.
This was at a time when animal behaviour was seen as instinctive responses to environmental stimuli.
He and his colleagues at UCLA, Berkely and Davis, analysed calls for roosting, food-seeking, mating, territory-marking, danger warning and mobbing. Their studies embraced language-learning in birds from a babbling phase, imitating parents to experimentation.
Later, Dr Marler went to Uganda in Africa to study primates, hoping to also detect language-learning patters similar to birds.
He was disappointed but he found ververts, long-tailed monkeys, did not learn calls from their elders but communicated with a precision no one had studied before. His spectrographic records showed them using various snorts and barks for escape strategies warning of ground predators such as leopards and threats from the skies from eagles. High-pitched hissing warned of pythons, and approaching humans. Dr Marler suggested such calls were almost certainly ancestors of human speech.
Among animal behaviour scientists, Dr Marlar was best known for his role in nature-versus-nurture debates as with James L Gould in the 1980s he .proposed that the drive to learn new things was adaptive, and animals and humans both had it in their genes and, once triggered, the drives depended on nurturing. A colleague said of him that what made him such a rare scientist was that he combined great knowledge with the curiousity of a naturalist.
Peter Marler was born in Slough. His father was a factory tool-maker. He was a devoted birder since he first befriended a rook as a child He had two Ph.Ds in botany and ethology, from Cambridge and London University.