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(a)
(b)
10
8
Germany
6
Canary Islands/
German hybrids
4
Canary Islands
2
0
50
100
150
Time (days)
(c)
600
1.0
A
B
500
0.8
400
0.6
300
0.4
200
0.2
100
0
0.0
0
1
2
3
4
5
6
0
1
2
3
4
5
6
Generation of selection
(d)
F1 offspring of
British adults
Adults from Britain
N
N
W
E
W
E
BRITAIN
GERMANY
S
S
Young from SW Germany
N
CANARY
ISLANDS
W
E
S
Fig. 1.3 Blackcap migration. (a) Male blackcap with nestlings. Photo © W. B. Carr (b) Migratory restlessness
(measured in cages) during the time of autumn migration in blackcaps from Germany, the Canary Islands and F 1
hybrids of these two populations. From Berthold and Querner (1981). Reprinted with permission from AAAS.
(c) Artificial selection in aviary populations for higher (red) and lower (blue) migratory behaviour in a partially
migratory blackcap population from southern France; A: frequency of migrant individuals; B: migratory activity
in migrants. From Berthold et al . (1990) and Pulido et al . (1996). (d) Traditionally, in autumn blackcaps from
southern Germany migrate in a south-west direction to winter in the western Mediterranean region. During the
past 40 years a new migration habit has evolved, with some blackcaps migrating west to Britain; F 1 offspring
from these adults inherit the new direction. Each point in the circles to the left refer to the direction of migration
of one caged individual and the arrows indicate the mean direction). From Berthold et al . (1992). Reprinted with
permission from the Nature Publishing Group.
 
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