The Eurasian Sparrowhawk (Accipter Nisus) is well-known as a wintering bird in Japan. Most ornithologists currently believe that most of the birds wintering in Japan are birds that breed on the Asian subcontinent, in areas such as NE China (Shinji Takano). After breeding they then migrate south along the Korean Peninsula, and over the Sea of Japan to Japan (Morioka et al.).
Between 1998 and 2000 I conducted 2 surveys in Korea, which were to confirm the migration route(s) and numbers of Eurasian Sparrowhawks and other raptors migrating through Korea, on their way to Japan.
In October 1998 I recorded mainly Eurasian Sparrowhawks migrating over 2 areas on the southern tip of the Korean Peninsula. The first was on the Yongdo-gu Peninsula, SE of Pusan City and the second was Kochedo island(unpublished report).
In October 2000 I carried out a second survey on the Yountoku Peninsula. On the second survey I recorded not only the migration of Eurasian Sparrowhawk but also the 2 other commoner species of accipter – Northern Goshawk (Accipter gentilis) and Japanese Sparrowhawk (Accipter gularis) and several other raptors.
In the spring of 1998 I also witnessed Eurasian Sparrowhawks migrating north over the Saozaki tip on the Northern tip of Tsushima island in Nagasaki Prefecture.
The main area of the survey was on the Yongdo-gu Peninsula, to the SE of Pusan City. The Peninsula is actually an island connected by 2 bridges to the mainland.
The main observation point was an 80 meter observation tower, in Taejongdae Park, at the Southern end of the island.
The observation point is about 50km from the northern tip of the island of Tsushima, and can easily be seen when weather conditions are good. Therefore I felt this observation point offered the best chance of viewing raptors migrating between the tip of the Korean Peninsula and Tsushima.
10x magnification binoculars were used to observe the birds migrating.
Summary
of October 1998 and 2000 surveys
In the survey, of 25-28th October 1998, observations were made over 3 days. Three species of accipters were recorded migrating from Korea to Tsushima. 287 accipters were recorded in all. 282 of the birds recorded were seen to migrate to Korea, while 5 birds returned to the mainland. Moreover of the 282 accipters recorded migrating, 280 were definitely identified as Eurasian Sparrowhawk, while the other 2 birds could only be identified as Accipter sp. .
In the survey of 12-18 October 2000, observations were made over 7 consecutive days. In total, 707 raptors of 9 species were seen to migrate over the 7 days. Around 90% of all the birds observed were seen migrating to Japan. 637 of the migrating raptors were identified as Eurasian Sparrowhawk, Northern Goshawk, Japanese Sparrowhawk or Accipter sp . About 10% of birds recorded were seen to return to the mainland. In all 68 birds returned to the mainland, 51 were Eurasian Sparrowhawk, 7 Northern Goshawk, 1 Accipter sp. and 9 Common Buzzard (Buteo buteo).
Weather
conditions and results of October 2000 survey
A sample from the results from the October 2000 survey suggests Eurasian Sprrowhawks prefer to migrate in fine, sunny conditions, or to a lesser extent cloudy conditions but not during rain. Table 2 shows that on the 13th October 105 Eurasian Sparrowhawks migrated between 6.50am and 12.53pm during fine weather conditions, with the wind-speed measuring only 2 on the Beaufort scale. In contrast on the 17th October, only 46 Eurasian Sparrowhawks migrated between 6.41 and 9.26 in cloudy conditions, this was prior to rain beginning to fall.
Optimum
migration group numbers
From data gathered during the October 2000 survey it would also appear that all 3 species of accipter prefer to migrate in groups usually no larger than 3, and only collected in larger concentrations for short periods of time. The largest number of Eurasian Sparrowhawks seen migrating together at the same time was 12 on the 15th October at 11.20am. The largest number of Northern Goshawks together was even lower at 7 on the 17th October at 2.50pm. No more than two Japanese Sparrowhawks were seen to migrate together at the same time.
It would appear that Eurasian Sparrowhawks and Northern Goshawks were mostly migrating singly or in groups of 2 or 3. Usually between 1 and 3 Eurasian Sparrowhawks would circle above the observation point at any one time, sometimes being caught up by another group to temporarily form a larger group, before leaving the group to migrate one by one.
Direction
of migration
From the observation point the direction most birds of prey (including Eurasian Sparrowhawks) migrated in was South East towards Tsushima. However, on rare occasions some raptors flew (further to the) East, in the direction of Mishima Island, off the coast of Yamaguchi Prefecture. Few Eurasian Sparrowhawks were observed to migrate to the East.
However, the birds that did migrate in an Easterly direction were further away and therefore more difficult to observe than birds migrating to the SE. The birds migrating South East flew directly above the observation point, whereas birds migrating to the East flew along the more distant Eastern shoreline of the island.
Other
visible migration
There were many non-raptor species seen
migrating towards Tsushima during the October 2000 survey. The most easily observed of the other
non-raptors migrating were the large groups of Brown-eared Bulbul, which migrated in groups of between 40 and 250.
3 Tables
of results for October 1998
and 2000 surveys
Table 1. A breakdown of the migration times, migration status (i.e. migrating or returning) number of birds, and weather conditions of October 1998 survey.
|
Date |
25.10.98 |
26.10.98 |
27.10.98 |
3 days hourly total |
||||
|
Weather |
Sunny |
Sunny |
Sunny |
|||||
|
Survey
start time |
9.40am |
7.00am |
7.45am |
|||||
|
Survey
finish time |
3.50pm |
1.00pm |
12.40pm |
|||||
|
Time |
M |
R |
M |
R |
M |
R |
M |
R |
|
7.00 |
|
|
13 |
0 |
1 |
0 |
14 |
0 |
|
8.00 |
|
|
11 |
0 |
9 |
0 |
20 |
0 |
|
9.00 |
0 |
0 |
21 |
0 |
8 |
0 |
29 |
0 |
|
10.00 |
19 |
0 |
21 |
0 |
13 |
0 |
53 |
0 |
|
11.00 |
57 |
0 |
25 |
0 |
33 |
0 |
115 |
0 |
|
12.00 |
22 |
0 |
7 |
0 |
14 |
0 |
43 |
0 |
|
13.00 |
8 |
2 |
|
|
|
|
8 |
2 |
|
14.00 |
0 |
3 |
|
|
|
|
0 |
3 |
|
15.00 |
0 |
0 |
|
|
|
|
0 |
0 |
|
Total number of birds |
106 |
5 |
98 |
0 |
78 |
0 |
282 |
5 |
Table
2 A breakdown of
the migration times and status of
Eurasian Sparrowhawks
during October 2000 survey period.
|
Date |
12.10. |
13.10 |
14.10 |
15.10 |
16.10 |
17.10 |
18.10 |
Total |
||||||||
|
Time |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
|
6.30 |
|
|
3 |
0 |
|
0 |
0 |
0 |
14 |
0 |
8 |
0 |
7 |
0 |
32 |
0 |
|
7.00 |
|
|
3 |
0 |
|
0 |
3 |
0 |
8 |
0 |
2 |
0 |
18 |
0 |
34 |
0 |
|
7.30 |
|
|
6 |
0 |
|
0 |
0 |
0 |
8 |
0 |
1 |
0 |
8 |
0 |
23 |
0 |
|
8.00 |
|
|
5 |
0 |
1 |
0 |
5 |
0 |
7 |
0 |
18 |
0 |
3 |
0 |
39 |
0 |
|
8.30 |
|
|
0 |
0 |
1 |
0 |
23 |
0 |
7 |
0 |
7 |
0 |
9 |
1 |
47 |
1 |
|
9.00 |
|
|
4 |
0 |
3 |
0 |
11 |
0 |
25 |
0 |
10 |
0 |
0 |
0 |
53 |
0 |
|
9.30 |
|
|
3 |
0 |
6 |
0 |
19 |
0 |
8 |
0 |
0 |
0 |
0 |
1 |
36 |
1 |
|
10.00 |
18 |
0 |
6 |
0 |
9 |
0 |
7 |
0 |
7 |
0 |
0 |
1 |
0 |
0 |
47 |
1 |
|
10.30 |
22 |
0 |
30 |
0 |
6 |
0 |
12 |
0 |
3 |
0 |
0 |
7 |
0 |
0 |
73 |
7 |
|
11.00 |
11 |
0 |
10 |
0 |
11 |
0 |
19 |
0 |
9 |
0 |
0 |
0 |
0 |
0 |
60 |
0 |
|
11.30 |
4 |
0 |
6 |
0 |
0 |
0 |
20 |
0 |
0 |
4 |
0 |
0 |
0 |
0 |
30 |
4 |
|
12.00 |
1 |
0 |
14 |
0 |
0 |
0 |
6 |
3 |
0 |
0 |
0 |
0 |
0 |
0 |
21 |
3 |
|
12.30 |
0 |
5 |
15 |
3 |
0 |
0 |
0 |
1 |
0 |
3 |
|
|
|
|
15 |
12 |
|
13.00 |
0 |
1 |
0 |
16 |
|
|
0 |
0 |
0 |
0 |
|
|
|
|
0 |
17 |
|
13.30 |
0 |
4 |
0 |
0 |
|
|
0 |
1 |
0 |
0 |
|
|
|
|
0 |
5 |
|
14.00 |
0 |
0 |
0 |
0 |
|
|
|
|
|
|
|
|
|
|
0 |
0 |
|
Total |
56 |
10 |
105 |
19 |
37 |
0 |
129 |
5 |
96 |
7 |
46 |
8 |
45 |
2 |
514 |
51 |
Table 3 A record of the numbers and migration status of all raptor
species recorded, during the period of the October 2000 survey.
|
Date |
12.10 |
13.10 |
14.10 |
15.10 |
16.10 |
17.10 |
18.10 |
Total For Each Species |
||||||||
|
Weather |
Sunny |
Sunny |
Sunny |
Sunny |
Sunny |
Cloudy |
Cloudy |
|||||||||
|
Rain |
||||||||||||||||
|
Survey
start time |
|
|
|
|
|
|
|
|||||||||
|
Survey
end time |
|
|
|
|
|
|
|
|||||||||
Migration status |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
M |
R |
|
Raptor
species |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Eurasian Sparrowhawk |
56 |
10 |
105 |
19 |
37 |
0 |
129 |
5 |
96 |
7 |
46 |
8 |
45 |
2 |
514 |
51 |
|
Northern
Goshawk |
6 |
3 |
7 |
1 |
5 |
0 |
19 |
2 |
7 |
0 |
20 |
1 |
10 |
0 |
74 |
7 |
|
Japanese
Sparrowhawk |
0 |
0 |
4 |
0 |
1 |
0 |
2 |
0 |
3 |
0 |
0 |
0 |
12 |
0 |
22 |
0 |
|
Accipter
sp. |
3 |
0 |
1 |
0 |
7 |
0 |
4 |
0 |
2 |
0 |
1 |
0 |
9 |
1 |
27 |
1 |
|
Osprey |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
2 |
0 |
|
Grey-faced
Buzzard |
0 |
0 |
0 |
0 |
0 |
0 |
2 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
|
Rough-legged
Buzzard |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
|
Common
Buzzard |
0 |
0 |
1 |
2 |
26 |
2 |
17 |
0 |
11 |
3 |
2 |
1 |
0 |
1 |
57 |
9 |
|
Eurasian
Hobby |
1 |
0 |
1 |
0 |
0 |
0 |
2 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
5 |
0 |
|
Eurasian
Kestrel |
0 |
0 |
0 |
0 |
2 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
2 |
0 |
|
Harrier
sp. |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
|
Total
of all birds |
67 |
13 |
119 |
22 |
78 |
2 |
175 |
7 |
122 |
10 |
69 |
10 |
77 |
4 |
707 |
68 |
514 accipiters were recorded migrating during a survey at Yongdo-gu, Busan from the 12th-18th Oct. 2000.
I have tried to come to some conclusions regarding the peak period of accipter migration and the peak time of day using the results of this survey and other past anecdotal records.
I observed 45 accipiters migrating from the N.W. over the tip of Cape Saozaki, on Tsushima island during another survey on the 9th October 1998 from 6:00 am to 4:00 pm. This was the earliest example I have of accipter migration( Yamada unpublished).
I also observed 7 accipters migrating from the NW over Tsunoshima, an island in Yamaguchi Prefecture in Western Honshu, Japan, in a survey on the 5th Nov. 2000 from 7:00 am to 5:00 pm. This is the latest example I have recorded of accipter migration.
Based on these observations I believe that the migration of accipters into Japan (from the Korean Peninsula) begins in early October and continues into early November.
The earliest time that migration was observed was at 6.30 am, when six accipters were recorded on the 16th Oct. 2000 at Yongdo.
The latest time for migration I observed was 3 accipiters migrating at 1:29 pm on the 25th Oct. 1998.
However, 1 accipiter migrated from the NW over the tip of Cape Saozaki and 2 accipters were recorded (but not seen to come in off the sea) at 3:58 pm on the same day at the same site.( Yamada unpublished ).
It would seem that most accipters have a tendency to cross the sea in the early morning because the distance is only 50km from the southernmost tip of the Korean peninsula to Tsushima.
Not only Eurasian Sparrowhawk , but also Northern Goshawks(Accipiter gentills) and Japanese Lesser Sparowhawks(Accipiter gularis) were frequently seen hunting smaller birds for instance Brown-eared Bulbul(Hypsipetes amaurotis) and Japanese White eye(Zosterops japonica) at any period of time during the day.(Yamada unpublished).
The biggest flock of migrating accipters I observed were 12 Eurasian Sparrowhawks, and 7 Eurasian Goshawks respectively. The biggest flock to turn back to land was 13 accipters recorded at 1:20 p.m. on the 13th Oct,2000.
As well as Busan, I survey Hon-po、the southern tip of Kojedo island, Kyongsangnam-do on the 27th Oct.1998 (from 7:40 am to 5:00 p.m.) and recorded 24 accipters flying mainly in a SE direction.
However, Eurasian Sparrowhawks and Eurasian Goshawks were also recorded migrating from W to E in the fall season not only at Saozaki and Tsunoshima but also the Yuya Peninsula in Yamaguchi Prefecture (Tadashi Kawahara 2000 ).
From the observations we have made I believe that there are many, complicated migration routes between the Korean peninsula and Western Japan. Therefore it is difficult to make clear conclusions about the numbers and the migration period of continental accipters (that are breeding on the Eurasian landmass and migrate to Japan for the winter) from our data.
In the future I would like to make further surveys in order to make clear the real state of migration through the united efforts of greater numbers of birders and birdwatching groups in Korea and Japan.
I am very grateful to Dr. Yukio Fukumoto, the President of Hiroshima Asa Zoological Garden for his help in completing my paper.