Short abstract from the book: The rook is a common breeding bird in most of Denmark,
though is most abundant in eastern parts of the country. In
October–November and March–April passage migrants are
observed in Denmark. The first rook was ringed in 1921, with the majority ringed in the early 1980s. Seventy per cent of the
recovered birds were ringed on Zealand, 16 % on Lolland-Falster, 5 % on Funen and 9 % in Jutland. At least 70 % of
the recovered birds were from the Danish population, either
ringed as chicks or as adults in the breeding season. Most
of the Danish rooks are residents. Only nine were recovered
more than 100 km from the ringing site, of these three outside
Denmark. The mean distance between ringing and recovery
site of the remainder was only 11 km, and 72 % were recovered within 10 km of the ringing site. Some young birds have
been found already in late May up to 30 km from the ringing
site, but the mean distance is only 2 km in June, 5 km in July,
10 km in August and 18 km in September–October.
Some of the rooks ringed as chicks were recovered in the
breeding colony both as a one-year-old and older. The mean
distance between ringing and recovery site for rooks ringed
as chicks and recovered in the breeding season as adults was
11 km. Rooks ringed or recovered in Denmark outside the
breeding season come from Norway, Sweden, Finland, the
Baltic countries, Poland, Belarus and Russia. The majority
of the migrants probably remain in Denmark throughout the
winter, since only a few of the ringed birds have been recovered further south. Thirteen rooks ringed in October–April in
Germany and one in Belgium have, however, been recovered
in Denmark.
Read more about the species in the chapter from The Danish Bird Migration Atlashere
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