Mass mortality of migrants

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Redwings Turdus iliacus migrating through a rainstorm at sea

Chapter 28

Mass mortality of migrants Migration is a season full of peril for great numbers of winged travellers. (W. W. Cooke 1915.) Great numbers of migrating birds, chiefly warblers, had accomplished nearly 95% of their long flight and were nearing land when, caught by a norther, against which they were unable to contend, hundreds were forced onto the waters and drowned . . . . During the fall migration of 1906, when thousands of birds were crossing Lake Huron, a sudden drop in temperature, accompanied by a heavy snowfall, resulted in the death of incredible numbers. Literally thousands were forced into the water and subsequently cast up along the beaches, where in places their bodies were piled in windrows. On one section of the beach their numbers were estimated at 1,000 per mile, and at another point at five times that number. (Frederick Lincoln 1935.) Despite its overall benefits, migration is often perceived as hazardous. During their seasonal journeys, migrating birds must travel through unfamiliar areas, and often through alien habitat, making it more difficult than usual for them to find food and avoid predators. They may run out of fuel, suffer from exhaustion,