DMU's (Danish National Environmental Research Institute's) bird count from aeroplane at Horns Rev on 9 April 2002
On 9 April 2002 DMU-COAST (Danish National Environmental Research Institute) made its latest bird count from aeroplane at Horns Rev. The counted transect lines can be seen from the figure below. An area towards north-east had to be omitted as a military restriction area prevented admittance the entire day.
Below the number of selected species has been listed, which were observed during the count. The most numerous species was the common scoter (Oidemia nigra).
|
Species |
Number |
|
Diver
(Gavia) |
138 |
|
Gannet
(Sula Bassana) |
1 |
|
Grey
lag-goose (Anser anser) |
44 |
|
Eider
(Somateria mollissima) |
75 |
|
Common
scoter (Oidemia nigra) |
3802 |
|
Velvet
duck (scoter) (Oidemia fusca) |
5 |
|
Herring
gull (Larus argentatus) |
804 |
|
Great
black-backed gull (Larus marinus) |
3 |
|
Little
gull (Larus minutes) |
127 |
|
Artic/common
tern (Sterna hirundo/macrura) |
1 |
|
Sandwich
tern (Sterna sandvicensis) |
2 |
|
Tern
(Sterna) |
2 |
|
Razorbill
(Alca torda)/Guillemot |
3 |
3,802 common scoters were counted and their distribution in the area can been seen from the figure. The number of common scoters differs significantly during counts made in April. On 27 April 9,230 species were counted and on 21 April 16,902 common scoters were counted whereas only 75 common scoters were spotted during a count made on 20 April which was of significantly shorter duration than the succeeding ones. Thus, the number of common scoters made during this count must be categorised in the lower end.
During the autumn and winter most of the common scoter are spotted in the waters west of Skallingen and Fanoe. During March and April the birds tend to be seen further from the shore, closer to the south-east flank of Horns Rev proper. This tendency repeats itself during this count, which can been seen from the figure. The reason for this regular change in the distribution is not known, however, the lack of food reserves in the areas in which the birds have been spending the winter could be one explanation. Another possibility is that at this time of the year new sources of food emerge at Horns Rev, which the common scoters find very attractive, e.g. eggs of sand eel.
In addition 138 divers and 127 little gulls were also observed during this present count. These species were mainly seen in the western part of the area, and especially to the north-west.
The 44 grey lag-geese came migrating towards north far from the coast south of Blåvands Huk.