GREY HEADED WOODPECKER (Picus canus)
This bird is nowhere near as common as the Green Woodpecker to which it is closely related. In Switzerland it is found only below 600m and over the last 40 years the population has declined and retreated to the north and east of the country. The few times that I have encountered it has been on semi-degraded or abandoned agricultural land not too far from forest.
It could well be that it is overlooked a lot, because not only is it rather similar in appearance to the Green Woodpecker (although slightly smaller and having a bland-looking grey head and face) but it also calls in a rather similar manner – a sort of semi-hysterical laugh. However there are differences - Grey-headed is slightly higher in pitch and with a squeakier timbre – rather like a Green with a sore throat:
Here are the two side by side for comparison three different Green calls separated by the same Grey-headed call:
And the sonogram for comparison of the two:
I can notice a few differences here: the Green seems to give a “happier” more laughing note of a richer timbre, the Grey -headed is sharper, higher, more precise and slightly mournful. If we look at the sonograms of each in more detail we can see some features that create these impressions:
The Green starts at about 1.2kHz on a rising inflection,
with energy (probably a harmonic) also between 2.5 – 3.2 kHz, this will make the
richer sound and that rising inflection makes it more joyful in “feel”.
The Grey-headed starts at 2.3 kHz and
descends to about 1.7 kHz and the energy seems concentrated there – hence it
sounds more squeaky (higher) more precise (less dispersed energy) and I believe
the downward inflection gives it a more mournful feel. You can find this mournful characteristic also
in the Black Woodpecker.
Like the Green Woodpecker the Grey-headed also calls rather intermittently, this one gave a single call every 30 – 90 seconds, here is a piece where the first two calls are at a natural interval and the rest I have shortened the period between them:
Two nice Woodpeckers and it is interesting to see what differences
we can find when we look at the detail.