23rd May, 2019 Birdsong in Places of Resort 2.
When considering birdsong a distinction needs to be made between ‘song’ and ‘call’. The former is more complex and often has melody, whereas the latter is usually more strident and monotonous, an alarm signal warning of an approaching threat. Blackbirds have a particularly loud alarm call which, in my experience, is recognised as such by other birds and mammals, a form of species interaction. Male (cock) pheasants also have a loud alarm call given out when they take to the wing to escape (evolution hasn’t yet accepted that this puts the species at a singular disadvantage if the predator has a gun). Generally, in my experience, it is the blackbird that is the last to stop ‘singing’ at dusk and the first to be ‘singing’ before dawn which means that in May, June and July they are giving themselves only about five hours rest, and yet their hard work pays off as they remain one of the most common garden birds.
The song of the skylark (‘the lark ascending’) doesn’t seem to comply with the ‘song’/’call’ distinction. When hovering above ground their ‘song’ is initiated in response to a threat and yet is sweetly melodic, perhaps a strategy to divert the attention of the threat away from its nest on the ground. Incidentally skylarks are unlikely to be a bird of the municipal park as they nest on the ground usually on arable land, if on grass they would quickly be made extinct by the grass-cutter. Picture above copied from Collins Complete British Wildlife, p. 108.
Some birds have non-vocal methods of communication, a cock pheasant ‘thudding’ its wings, woodpeckers ‘hammering’ tree trunks or branches. Charles Darwin referred to this as ‘instrumental music’. Sound waves from a woodpecker’s ‘drumming’ reverberates across a long distance. I used to hate heading the ball when playing football, surely it could do harm, and now the pendulum is swinging my way. The woodpecker’s skull has so evolved as to prevent his drumming causing brain damage.
One more comment on birds audible communication is that some species keep in-touch while flying in the dark/migrating. Particularly noticeable in the Humberside region in this respect are geese.