BLACK KITE (Milvus migrans)
The Black Kite is a summer visitor across most of Europe - the western Europe populations spending the winter in sub-Saharan Africa. In Switzerland they can be seen from about mid-March onwards, breeding adults leave at the end of July and the young birds a few weeks later, by September they are rarely seen.
A magnificent bird of prey with a forked tail which it uses as a rudder to steer as it floats steadily around looking for food. However it rarely takes live prey and is predominantly a scavenger feeding on edible waste and animal carcasses - it seems to be especially fond of dead fish on the margins of Swiss lakes. Hence it is usually seen slowly circling over likely spots for food. I have seen large assemblages in refuse areas if any type of edible waste is available, they will also congregate in large numbers when grass or wheat fields are being cut and insects and small mammals may be exposed.
It communicates by means of a far-carrying call which I have named its "long call". This starts as a piercing whistle tailing off into a rather tremulous wailing sound - quite unmistakable. This can be uttered both on the wing, either alone or when interacting with another bird, or when perched. It does not call regularly so the following file is a composite of three different sequences to shorten the time-line:
The tremolo effect on the second part of the call can be clearly seen in the sonogram:
Here is another example from a bird calling more regularly near a nest - they seem to be more vocal close to their nests
BUZZARD (Buteo buteo)
The Buzzard is perhaps the most common bird of prey in Switzerland.Most often seen when it is circling overhead, it is easily told by its darker secondary feathers under the wings, often showing a very clear "thumb-patch" at their outer edge. The birds in the Lac Leman region also show a very clear pale band across the lower breast - easily seen when they are perched, and they can often be seen in this position in winter when they stay at lower elevations and sit on fence posts in farmland.
They are very vocal but with a pretty limited repertoire - the call is a plaintive "mee-aaah", quite harsh, rising sharply and then trailing away. It carries over long distances and so is often heard faintly in the distance- but here is a bird that was perched only about 50m away from me:
(Yes that was a donkey braying at about 8s in to that last recording !)
Sonograms of Buzzard calls always shows a lot of harmonics but the main energy of the call is between 2 - 2.6 Khz.
This call is pretty much all they do - even in flight, here are a group of Buzzards in January that were circling overhead calling to each other:
There are small variations of course, most often around the nest or when two birds interact, here is another recording of a single bird that seems to be a shorter, rather more blunt call:
Within forest areas, one of the calls of a Jay sounds very much like a Buzzard, I have read that Jays may do this to avoid predation by Goshawks, but I am a little sceptical of that theory.
If we compare sonograms of the two on the same scale it can be seen that the two are indeed a remarkably similar shape but the Buzzard call lasts for about 1.5 secs whereas the jay lasts about half a second, also the Jay descends to a lower frequency than the Buzzard. I reckon that any Goshawk worth its salt could tell the difference ! The Buzzard comes first in the following comparison:
KESTREL (Falco tinnunculus)
The Kestrel is the most common falcon in Switzerland and probably throughout western Europe. It is almost unmistakable in both appearance and behaviour. The adult birds have rich brown wings with dark tips and the tail, which in the male is blue-grey like the head, has a black terminal band which is easily seen.
It is common in most habitats from the agricultural lowlands to the high alps up to about 2,500m. This is the bird that is seen hovering as it looks for prey. Fast direct flight is often followed by a banking turn to face the wind, it then spreads its wings and tail, lowers its head and by using its wings in a humming-bird type of motion stays stationary whilst it searches the ground below for suitable food. In the mountains in an updraught this can be done with no wing movements at all, just letting the upwards movement of air take its weight and hold the bird motionless. This behaviour is also a tribute to the excellent eyesight of birds of prey when you realise that most of its food is small mammals (voles - campagnol) and insects like grasshoppers (sauterelle) and beetles (col√©opt√®re).
Like most birds of prey Kestrels are generally quiet, and calls that I have heard are usually in the vicinity of a nest or when two birds are interacting. The most common call I know is a high pitched "whickering" ki-ki-ki-ki. Here is a bird some distance away sailing across a cliff calling, it was a hot day in August so there is much insect noise and cows bells echoing off the cliff:
This ki-ki-ki call is one of two clear calls I have identified from adult Kestrels. The other is a more rolling whinnowing call. I recently found a pair of Kestrels with 3 young that had just left the nest - I could see the nest on a nearby cliff ledge and although the young were flying with the adults they were still begging for food. I heard the female making this whinnowing call as she first sat and then circled a tall dead tree above me:
In the background you can hear the other bird (the male) answering with the ki-ki-ki call from further down the valley.
Here is the reverse, with the parabola turned on the male and you can hear the whinnowing call from the female in the background:
However my observations that day make me believe that both birds can make both sounds - here is the male as I followed him flying near to the turbine systems of the nearby dam, he first makes the whinnowing call and later (at about 15s) switches to the ki-ki call:
As I said, the three young birds were clearly only very recently out of the nest and the whole family was flying around in a very excited manner. I watched the female land on a large rock, she was immediately approached by a young bird which let out two whistles then, with neck outstretched and wings down in a begging posture proceeded to call at the female in a manner very similar to the whinnowing call used by the adults:
So my conclusions are that even in these family interactions Kestrel vocabulary is somewhat limited. To round off this conclusion here was a completely different group of birds (three in total but too far away for me to identify the sexes) who were seeing off a Black Kite which had been patrolling the cliffs where I assume the Kestrels were nesting - the three of them kept diving at the Kite making these by now familiar sounds: