"There is direct evidence that birds lose themselves 

 in foggy weather." William Eagle Clarke, Studies 

 in Bird Migration 



12 



The Influence of Bad Weather 



Ihere persist some hallowed legends about 

 migration carried from one generation to the next until by the authority of 

 age they live unquestioned. One such is a belief that migrant birds are able 

 to navigate through fog to their destinations. Lincoln ( 1950b ) tells us that 

 "we know that vision is not the sole reliance as some birds fly unerringly 

 through the densest fog." He cites the observation of Cooke (1915), made 

 when the latter was on a steamer "en route from Unalaska to Bogoslof 

 Island in the Bering Sea, proceeding cautiously through fog so dense as to 

 blot out all objects at a distance of 100 yards. About halfway across, flocks 

 of murres, returning to their nests on Bogoslof, began to break through the 

 wall of fog astern, fly parallel to the vessel and disappear into the mists 

 ahead. The ship, with the aid of compass and chart, was headed directly 

 toward the island, but its course was no more accurate than that followed 

 by the birds." 



Let us mark first that this was a local movement of sea birds in their 

 native environment where they traveled from feeding grounds to nesting 

 place. As they were within sight of the sea, their height was not more than 

 100 yards, while the breadth of travel was somewhat less than 200 yards. 

 Unalaska is 60 miles from Bogoslof. The murres were encountered about 

 halfway; hence their destination was 30 miles from the point where first 

 seen. In fairness, as they came from behind, let us guess that the whole of 

 their journey was at least 40 miles. If flying at about 40 miles an hour, their 

 time on the wing would have been an hour. As such, the flight was com- 

 parable to a four-mile walk by a man through fog. While admittedly no 

 "landmarks" were available to the murres, they started from their familiar 

 feeding place toward the sexual goal at the nest and all the way were in 



163 



