渡りの終末

渡りの終末

渡りを放棄したホシハジロ
五羽が三羽となり本日は零
北と南を旅する冬鳥の生態
力つきた渡り鳥に四季が襲う
The end of migration
Common Pochard that stopped the migration to north
Five wild birds were reduced to three and today zero
Ecology of winter birds traveling north and south
Four seasons attack a migratory bird