On the basis of 125 light-house struck specimens of the Gray's Grasshopper Warbler Locustella fasciolata, distribution, migration routes and their origins were discussed. Specimens were sent from the following light-houses: Mizunoko (Oita Pref.), Sada-misaki (Ehime Pref.), Kyoga-saki (Kyoto-fu), Hegura-jima (Ishikawa Pref.), Nyudo-zaki (Akita Pref.), Omae-zaki (Shizuoka Pref.) and Shiriya-zaki (Aomori Pref.). Specimens and sight records from many other light-houses in Honshiu, Hokkaido, Southern Kuriles, South-west of Korea, northern Formosa since 1924 were also taken in consideration. The breeding grounds of this species are from the upper basin of the Yenisei River to Amur district ranging from the south of 55°NL. and north of Hokkaido, and wintering grounds are Philippines, Celebes, Papuan islands etc. Spring migrants pass through Honshiu during late May and middle June, and autumn migrants during late August and early October. Thus, spring migration period is shorter than in the autumn. The breeding season is relatively short in this species and most birds are already in breeding condition on spring migration. It seems, therefore, that they reach the destination taking the shortest route soon to breed on arrival. In the autumn, on the other hand, they have finished their breeding and include young birds. Thus, they also take inland routes other than the shortest coastal passage. Four migration routes were suggested: 1) Philippines-East coast of Formosa-Riu Kiu-Honshiu-Japan Sea coast of Honshiu-Hokkaido-Kuriles and Sakhalin. 2) Philippines-East and west coasts of Formosa-Fuhsien-Chiensoo-South west of Korea-West coast of Honshiu and joins to 1. 3) Philippines-East and west coasts of Formosa-Fuhsien-Chiensoo-Korean Japan Sea coast and Usuri districts. 4) Philippines-Both coasts of Formosa- Fuhsien-Chiensoo-Shantung-North eastern China Upper basin of Yenisei River. Five possible migration routes in Honshiu were also suggested as follows: A) Riu Kiu-Bungo Channel-Osaka Bay-Wakasa Bay-Japan Sea coast of Honshiu-Hokkaido. B) Bungo Channel-the Sea of Suo-Japan Sea coast and joins to route A. C) Deviated from route A at Osaka Bay-Ise Bay central Honshiu-Hokkaido. D) Deviated also from route C at Osaka Bay-the Pacific coast of Honshiu and joins to C. E) South west of Korea-west coast of Honshiu and joins to A. Among the five routes, A and E are presumably the heaviest and D is practically very seldom used, especially in spring migration. The history of the present distribution and migration routes were also discussed. It was assumed that the earliest migration route taken in the geological age, was exclusively the route 1. However, other westward routes were later established with the change of coastal line caused by the submersion of land, and this westward swing of their migratory routes resulted the extention of their breeding range into Siberia.
The body weights, fat weight (amount of scratched body fat) and size of gonads taken from lighthouse struck and other birds are listed. The birds were preserved by Ishizawa's weak-formalin injection method (Tori no. 81). Although the rate of weight change by long preservation should be confirmed, there seems to be no appreciable difference between short time and long preserved specimens. Skin specimens could be made even from some birds preserved over 200 days. The scratched amount of fat was more or less one half of that extracted by Soxlet method in a few cases. Some note is given about the data of the list.
The authors found a great number of dead or dying Slender-billed Shearwaters, Puffinus tenuirostris, in Suruga Bay from May 23 to 26, 1964, when the plankton survey was made on the "Tansei Maru" of Ocean Research Institute, University of Tokyo. This phenomenon was observed almost in all parts of the bay, especially in the inner part. Fourteen dead or dying birds were observed in area, 150m in width and 10km in length, in the inner part. From this observation the total number of birds in this inner part was estimated at more than 4, 000. Four specimens were used for dissection. One of these was alive and three were dead when they were collected. Blood was vomitted in two specimens. Stomach contents were absent in three specimens and stomach bleeding was found in two and cloaca was filled with feces in one. The southern wind blew ashore frequently in this period, especially strongly on May 23 and the Kuroshio current was shifted to the south and water temperature was lower than usual. The cause of this mass martality could not perfectly be clarified, but judging from the results of dissection and meteorological and oceanographical data, the unusual sea current of this year caused the scarcity of food in the normal distribution sea area of this shearwater and would have forced them to prostraction, while the strong southern winds that followed drifted exhausted birds to the shore. The authors have no definite evidence to conclude whether this mass mortality was caused by some diseases.
On May 30 and 31, 1964, Umitaka Maru, a training ship of Tokyo University of Fisheries, cruised from Uraga, Kanagawa Prefecture to Osaka. On and after May 20, newspapers reported that great numbers of Slender-billed Shearwater, Puffinus tenuirostris have been washed ashore between Kiushiu and Mie Prefectures, western Pacific coast of Japan. Comparatively abundant Slender-billed Shearwaters were observed during the cruise and four specimens were obtained, of which two were weakened birds strayed on board and two others were dead birds drifted on the sea east of Kashinozaki, Wakayama Prefecture.
One example, a dead bird, was picked up in Nagano, August 30, 1964, after the typhoon no. 14 and the other, taken alive and released after fed, was found in Tokyo, September 26, 1964, after the typhoon no. 20. The passage of typhoons and positions of birds obtained are shown by a map.
162 short reports on 'land-birds at sea' scattered in ornithological literature were reviewed with annotation (Those the original was not available were listed by titles only), with the divisions of: Western Atlantic (42), Eastern Pacific (8), Eastern Atlantic (37), Western Indian Ocean (13), the Mediterranean (28) (Most of reports before comprehensive paper of Moreau, 1953 were listed by titles only), the Red Sea (9), Western Pacific and Japanese waters (18) and South Asian Seas and Eastern Indian Ocean (7). Land birds, chiefly Passerines, have been recorded at sea mostly during migration seasons from several to some hundred miles offshore, but accidentally over a thousand miles. Even not far from the coast, less than some 20 miles, birds have been reported to come to ships exhausted and were seen dead on the water. These cases suggest that they migrate off the shore rather than along complicated coastal lines, even though they may encounter stormy weather and become exhausted. Some of them may be drifted hundreds of miles over the ocean by seasonal winds blowing out from the continent. The records plotted on the map suggest the pattern of such drifts along both sides of North America, east coast of Kamchatka, in Western Indian Ocean and North Atlantic. However, regular over-sea migrants have also been recorded in which the birds may not come to the ship or only some of them resting for a while or staying on board to feed on insects or food given by the passengers. Migratory hawks may live on such small birds on board. They have sometimes been brought back many miles by ship and reports of American birds crossing the Atlantic to the British Isles on board are increasing in literature. A Peregrine Falcon is supposed to have reached Japan from Hawaii on board a ship feeding on petrels and terns. Although rare, even resident birds have been recorded at sea. As suggested by Williams in New Zealand birds, these may be due to winds, but in some cases birds may first fly out to the sea by some innate factors. The accidental records of highly migratory birds such as the House Swallow, Lanius cristatus, Halcyon sancta, etc. (see the map) to unusual direction far over the ocean may also involve innate factors.