CHAPTER VIII. 



THE PERILS OF MIGRATION, 



Mortality amongst Migrants — Dangers of Migration — Fatigue 

 of Migration Flight — Birds at Sea — Arrival of Exhausted 

 Migrants — Effects of Sudden Gales and Storms — Choice of 

 Sea Routes— Enemies of Migrants — Attraction of Light- 

 houses and Light Vessels — Influence of Fog-horns on 

 Migrants — Migration Streams visiting Lights — Telegraph 

 Wires and Migrants — Mortality amongst Woodcocks — 

 Instances of Striking Force of Migrants — Migrants losing 

 their Way — Instances of Abnormal Migrations in British 

 Islands — Instances in other countries — Abnormal Migration 

 at Heligoland — Gatke's Die Vogelwarte Helgoland — Heligo- 

 land compared with British Islands — Comparative Table of 

 Abnormal Migrants — Coincidence of Route of Abnormal 

 Migrants — Effects of High Rate of Mortality among 

 Migrants. 



The Migration of birds is beset with dangers and 

 full of perils. It would scarcely be possible to 

 over-estimate the mortality among birds of passage 

 directly due to migration. One very significant 

 proof of this great mortality is presented in the 

 fact that of the immense numbers of birds flying 

 south or west in autumn, only a very small per- 

 centage come north or east again in spring ! Most 



