BEAUFORT LF, DE , KLOMP, H & PERDECK, AC (1959) Annual Report of the Vogeltrekstation for 1958. LIMOSA 32 (3): 87-107.

Annual Report of the Vogeltrekstation for 1958 Experiments on orientation and ringing activities by A. C. PERDECK The first results of a displacement experiment with teal are reported. Experiments with migrant starlings in a Kramer-cage were continued. At the fowling-yard of the Voge1trekstation near the Hague 9016 birds were ringed in the autumn. A small invasion of Mealy Redpolls was observed there in the first half of November. The Dutch ringing scheme was taken over by the Vogeltrekstation and thoroughly reorganised (see the Ring, or. 17 p. 78). 2. Field observations by H. KLOMP and A. C. PERDECK The annual observations on visible migration of chaffinches and starlings 105in the surroundings of the IJsselmeer were continued. Moreover, observations have been done outside Holland, in order to obtain data concerning the standard direction of the Scandinavian chaffinch in different parts of its area of passage. This population has its wintering grounds mainly in the British Isles. Field observations suggest that the winterquarters are reached to some extent by crossing the northern part of the North sea. Quite a number of birds, however, fly along the eastern coasts of this sea, crossing it only under favourable weather conditions. Huge numbers reach Cap GrisNez in NW-France and cross the Channel in W-NW directions, as has been shown by earlier observations. Therefore, it is very likely, that here the birds use a method of orientation identical to that used in homing experiments (true goal orientation). To investigate whether this holds for the whole area of passage, the observations wen~ extended in 1958 to northern Holland, Jutland, Gris-Nez and the Cherbourg Peninsula (with Dutch observers). The results may be summarized as follows: 1. Central Jutland (22-26 Sept.). Migration very weak, results not thrustworthy (fig. 2). 2. South Jutland (27-28 Sept.). Standard direction about SW (fig. 2). The greater number of migrants suggests passage over the Danish Isles. 3. Northern-Holland (5-11 Oct.). Standard direction SW-WSW (fig. 3). 4. Central Holland (5-11 Oct.). Standard direction SW-WSW (fig. 4). 5. Cap Gris-Nez (18-24 Oct.). Standard direction WSW-NNW (fig. 5). 6. Surroundings of Cap Gris-Nez (21 and 23 Oct.) (fig. 5). Standard direction NW-N. Since no chaffinch populations breeding in South or Southwest France winter in England, it is concluded that the birds observed here belong to the Scandinavian population as well. They have probably left the coast under bad weather conditions and later on they resumed their migration to England. Part of these birds meet the coast south of Gris-N ez and follow it to the north (fig. 6). 7. Cherbourg Peninsula, Pointe Barfleur (24 and 28 Oct.). Migration weak, both chaffinches and starlings left the coast in NE and E directions. Although the observed directions need further confirmation, it is evident that Scandinavian chaffinches even reach this peninsula, a point not yet checked earlier. 8. Cherbourg Peninsula, Cap de 1a Hague (29-31 Oct.) (fig. 6). No chaffinch migration; moderate starling migration, heading for England in NNW-NWbyW directions. As far as the chaffinch is concerned, these observations prove that the standard direction of the Scandinavian chaffinch is not the same in various parts of its area of passage. Going from north to south it changes from SW over WSW till NW or even NE. This supports the idea that over the whole route of migration true goal orientation is involved. The starling shows a similar trend. Displacement experiments have shown that this type of orientation is present only in adult starlings and chaffinches. The juveniles keep to a certain point of the compass only (one-direction orientation). However, one cannot assume that the flocks leaving Gris-Nez are being composed of adult birds only. 'The majority of both starlings and chaffinches folloWing the Dutch coastline 'are juveniles, and there is no reason to assume that the age ratio will change considerably if the migrants reach NW-France. Hence, it is very likely that in a mixed flock the adults determine the general direction. However, such an effect could not be demonstrated in displacement experiments with mixed flocks. Adults and juveniles then took different directions independently of each other. The Vogeltrekstation will continue this type of observations in 1959 and later years. It would, of course, be a great help if we could cooperate with foreign observers, and we hope that this can be realized next year.

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