5 november 2009
A lot has happened the last week. The delayed young Osprey from Hammarsjön that stayed for a long time in France has made an enormeous step foreward and has crossed the Mediterranean Sea and most of the Sahara desert!
The Mediterranean Sea crossing was very spectectular! Most adult Ospreys cross the sea near a narrow point such as Gibraltar or via Italy. Young birds normally just cross where they end up, which can result in a very long sea crossing (such as in this case).
This bird started the sea crossing in the morning (we lack early morning positions for this day, and pick the bird up at sea at 11:00). The bird passes Mallorca, but is does not stop there, at all three positions the bird was in flight. This is also obvious from the speed (distance between points), it does not slow down near Mallorca.
The last part of this crossing was made during the night. Ospreys very rarely fly during the night, in fact it only seems to happen in combination with long sea crossings. Flying over the sea costs a lot of energy as there are no thermals over water, the birds can thus not soar but have to flap actively with their wings. This day the Osprey travelled about 650 km, of which the largest part was over water.
The day after the impressive sea crossing the bird did not take a rest, but directly started, early in the morning, with the Sahara crossing.
Here the bird makes very good progress, travelling about 500 km per day.
The only thing that worries me a lot is the pattern in the end. The last 2 days the Osprey changed its course and is now flying due west. In this region strong easterly winds prevail, thus the bird is now 'flying with the wind'.
We have seen before that birds that get into problems during their travels suddenly change their heading so that they align with the wind. In this way they will gain maximum support from tailwinds, and thus maximize travel speeds. We interpret this behaviour as 'escape flights' as they seem to try to escape as quickly as possible from the desert. The last locations from the bird are a true cliffhanger. Here we see the bird flying over the sand dunes (not a good habitat for Opreys).
Has the young Osprey enough energy reserves left to reach the coast, where fresh fish is waiting, or will it die in the desert?
New positions will come after the weekend....
/ Raymond Klaassen