COLLARED DOVE (Streptopelia decaocto)
A common bird usually associated with human habitation - it is not difficult to see where the English vernacular name comes from ! However the origins of the species itself are from Asia - most likely India. Until the 1930's in Europe it was limited to the Balkans, whether it had been introduced there by man is not clear. But since then it has undergone an expansion of its range to the north and to the west, reaching Scandinavia in the 1960's, Iceland by the early '70s and Spain and Portugal in 1974.
Its call is a monotonous cooing - "coocoo,coo" - easy to remember as "no stew, cook", here is one in my village :
Like most of the family a low frequency call from 450 - 650 Hz with a distinctive downward slur on the "stew":
Because of the "coo-coo" nature of the call it is sometime mistaken for a cuckoo (by those who don't really know what a cuckoo sounds like !).
If you listen carefully the first two notes - "no stew" have a distinctive ring to them - this is because they are double notes. Below is a screen shot of the sonogram and there you can see that in each case there is an "A"note which is a brief precursor to the "B" note which is the main one you can hear, each pair delivered within a few milliseconds of each other - so even this boring little chap can get up to clever things !