Rook Corvus
f. frugilegus
This gregarious farmland corvid is locally common and 855000
pairs breed in Britain. However, here it is infrequent throughout most of the
year except during spring and autumn migration periods. Until 1986, the first in autumn appeared
from early to mid-Sept but since 1987 they scarcely appear from late-Sept. Peak passage is in mid and late-Oct and
usually only involves one or two on up to five dates but larger flocks rarely
occur including 44 on 26 Oct 1999, 40 NW on 15 Oct 1973, 29 on 16 Oct 1996 and
14 in late-Sept 1984. British birds are
mostly resident and the larger movements probably involve Dutch and some Scandinavian
and Baltic bred birds.
During the 1980s it was rather infrequent in winter but in the 1990s it
became rare with only five records within the period Dec to Feb. An old cold weather movement records ‘over a
thousand ‘crows’ flew W on 8 Dec 1967.
A light spring passage can occurs in some years from early-Mar to
late-Apr but the max count is only four N on 20 Mar 1998. Late birds scarcely appear through May but
then it becomes rare June to Aug with the only records in the 1990s being two 4
July, one 22nd & five 26 Aug 1994 and two 14 Aug 1998. Nearly all records are of birds flying over
and few have ever been seen grounded here, if at all they occur on the beach
and upon ‘woodhenge’. 636 birds-days on
245 dates in 20 years is an average of 31.8 per annum.
Table 214: monthly
(est min for 1980s) total bird-days and no of dates 1981 - 1999
Month
|
J
|
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
|
B-dy.s |
20 |
16 |
51 |
58 |
18 |
4 |
4 |
11 |
103 |
237 |
55 |
19 |
|
Dates |
11 |
10 |
27 |
39 |
13 |
3 |
2 |
6 |
29 |
68 |
25 |
12 |
Table 215: annual
total bird-days and no of dates
Year
|
1980 |
1981 |
1982 |
1983 |
1984 |
1985 |
1986 |
1987 |
1988 |
1989 |
|
Jan - June
|
B-dy.s
|
? |
2 |
9 |
7 |
21 |
13 |
16 |
16 |
6 |
7 |
July - Dec
|
B-dy.s |
? |
23 |
4 |
20 |
38 |
12 |
6 |
9 |
9 |
9 |
TOTAL
|
B-dy.s |
? |
25 |
13 |
27 |
59 |
25 |
22 |
25 |
15 |
16 |
|
Dates |
? |
14 |
11 |
16 |
20 |
17 |
17 |
14 |
9 |
10 |
|
Year
|
1990 |
1991 |
1992 |
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
1999 |
|
Jan - June
|
B-dy.s
|
8 |
5 |
9 |
2 |
4 |
7 |
0 |
5 |
21 |
0 |
|
Dates |
6 |
4 |
6 |
1 |
2 |
6 |
0 |
3 |
11 |
0 |
|
July - Dec
|
B-dy.s |
10 |
16 |
15 |
0 |
14 |
7 |
32 |
37 |
144 |
73 |
|
Dates |
7 |
5 |
6 |
0 |
7 |
3 |
4 |
11 |
22 |
13 |
|
TOTAL
|
B-dy.s |
18 |
21 |
24 |
2 |
18 |
14 |
32 |
42 |
165 |
73 |
|
Dates |
13 |
9 |
12 |
1 |
9 |
9 |
4 |
14 |
33 |
13 |
|