It is time again: In the next days the first alpine swifts should arrive in Freiburg.
When I walk through the streets and hear the calls of these birds, I realize that summer is just around the corner. All Central European Swift-species are migratory birds that are only here during summer.
In my opinion, they fascinate people because they live the dream of flying in the extreme: they spend their lifes in the air! They fly very fast with almost 100 km/h, they hunt insects in flight, they collect nesting material in flight, they drink while flying flat over a lake, they bath in the water by a short splash on the water surface, they sleep in the air and even the mating takes place in the air!
The only reason to land seems to be the raising of the brood. A recent accelerometer study found that some individuals of swifts spent the entire time in the air between the breeding seasons. The record is held by a bird that spent 314 days in the air without landing. These birds are so well adapted to their life in the air that they can not even take off if they land on the flat ground. The reason for this is that they have very short legs (they simply don’t need them). Normally you can’t see their feet either – but on hot days they sometimes keep their legs out of their plumage for cooling.
There several species of swifts in Europe with Common Swift beeing the most common.
The next similar species is the Pallid Swift, occuring in the mediterranean area (you have also seen the Pacific Swift in a former blogpost, which extremely rare reaches central Europe)
However in central Europe, just one more species is breeding: The Alpine Swift – the biggest of the species with a wingspan of about half a meter.
While the species used to breed only in rocks, it has now found alternative breeding sites in buildings.
The easiest way to discover a breeding site is to look for the excrement underneath.
Alpine swifts use narrow cracks to get into buildings.
Two years ago I was given the opportunity to join in ringing the young alpine swifts. The birds are ringed to see how the spread in Germany is progressing.
In 1955 there was the first brood of an alpine swift for Germany in Freiburg. The population has increased considerably and now there are more than 100 breeding pairs and the species has spread to Karlsruhe and Bavaria.
I look forward to meeting the birds in the next few days.