コハクチョウ・・・・日露間の平和大使
昨年末に、高崎市木部町の鏑川にコハクチョウが飛来しているか確認に行きましたが、その姿は見えませんでした。しかし、昨日の夕方、鏑川の土手をウォーキング中に１０羽ほどの白い姿を見たとき、思わず「よくここまで飛んで来たね」と心で思い、ホッとし、川岸まで行ったところ、逃げる様子はなく近くまで寄ってきました。時折、川底に首を入れ、何が食べてる様子です。この中には昨年ロシアで生まれた雛も親の後を追い、ここまで飛んで来た若いコハクチョウもいると想われます。
ところで、日本に飛来して来るコハクチョウは一体どこから飛んでくるのでしょうか。想像では、シベリア東部、及びカムチャッカ半島から南下してきたと考えられます。それでは、そこから高崎までの飛翔翔距離はどれ程でしょうか。
ご存じの通り、北極点から赤道までは約１万㎞ですから、１°の距離は１００００km÷９０°＝１１１km程です。カムチャッカ半島中央部は北緯５５°であり、群馬県・高崎市は北緯３６°ですから、両地点の緯度の差は５５°－３６°＝１９°です。１°の距離は１１１kmですから、１９°×１１１km＝２１０９kmとなります。しかし、実際にはカムチャッカ半島は日本の遥か東なので、本来ならばレース鳩の距離測定のように球面三角法で計算することになります。このため、実際の飛行距離は少なくとも３０００km以上と考えられます。
カムチャッカ半島と日本列島の間には千島列島が弓状に多数並んでおり、コハクチョウたちは、おそらく、これらの島々で休憩しつつ、幾日もかけて日本をめざし、ついに目的地の高崎にまで到着したのでしょう。誠にすごい長距離を自分の翼だけで飛んで来たのですから、すごい体力です。途中で悪天候や猛禽類との遭遇もあるはずです。私のウォーキング距離とは比較になりません。コハクチョウを見習い、これからも私は体力と精神力を鍛えます。
Dear my overseas friends who are interested in Nature and great music.
The simultaneous interpretation for your understanding will be done after my breakfast Japan time.
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At the end of last year, I went to the Kabra River in Kibe-town, Takasaki City, Gumma prefecture to check if there were any Tundra swans flying in, but I couldn't see them. However, yesterday evening, when I saw about 10 white birds while walking along the bank of the Kabra River, I couldn't help but think to myself, "They really flew all the way here," and I felt relieved. I went to the riverbank, and they didn't try to run away, but instead they came close to me. Occasionally they put their heads in the riverbed, as if they were eating something. Among them are probably young Tundra swans that were born in Russia last year and followed their parents to fly here.
By the way, where do the Tundra swans that fly to Japan come from? I imagined they came south from eastern Siberia or the Kamchatka Peninsula. So how far do they fly from there to Takasaki-city, Gumma Prefecture?
As you know, it is about 10,000 km from the North Pole to the equator, so the distance of 1° is about 10,000 km ÷ 90° = 111 km. The central part of the Kamchatka Peninsula situates at 55° north latitude, and Takasaki-City, Gumma Prefecture situates at 36° north latitude, so the difference in latitude between the two places is 55°-36°=19°. The distance of 1° is 111km, so 19° x 111km = 2109km. However, in reality, the Kamchatka Peninsula situates far east of Japan, so the calculation would normally be used spherical trigonometry, like measuring the distance of pigeon racing. For this reason, their actual flight distance is thought to be at least 3000km or more.
Between the Kamchatka Peninsula and the Japanese archipelago, there are many Kuril Islands lined up in a bow shape, and the Tundra swans probably took a rest on these islands while heading for Japan over many days, and finally arrived at their destination, Takasaki-city. They flew such a long distance using only their own wings, so they have incredible stamina. They must have encountered bad weather and birds of prey along the way. It's nothing compared to the distance of my walking. Following the example of the Tundra swans, I will continue to train my physical and mental strength.
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