MIGRATIONS OF WATERFOWL 



rise and sunset come earlier (relative to the time at home), and in west- 

 ward movement, later. A traveler accustomed to breakfast at sunrise, din- 

 ner at high noon, and supper at sunset would find that if he went several 

 hundred miles due east overnight, the next day's sun would have topped 

 the horizon before breakfast, passed its noon peak by dinner time, and set 

 before supper. If he went west from home, breakfast would arrive before 

 sunrise, the stomach would call for its dinner before the sun had gained its 

 zenith, and supper would start with the sun still in the sky ( Figure 23 ) . 



These changes in the sun are imperceptible, by men at least, in short 

 travels from home. It is only when they make long, swift journeys that they 

 are sensible of a change in the path of the sun relative to earth and time. 

 The sailor, with the wind behind his sails, was the first to understand how 

 sun position and schedule were related to his place in longitude and lati- 

 tude. The Ancient Mariner observed, as his ship sailed southward: 



The sun came up upon the left 



Out of the sea came he! 

 And he shone bright, and on the right 



Went down into the sea. 



Higher and higher every day 

 Till over the mast at noon — 



So it is, the sun serves man in two ways according to the distance and 

 velocity of travel. In short trips close to home, the sun is a cue to compass 

 direction. But if a man is lost, displaced from familiar surroundings, the 

 sun is not a guide to the direction home, even though it still serves as a 

 reference to north. A given direction may be followed, if the sun is in view; 

 but one must locate familiar surroundings before perceiving the direction 

 to home. 



As a man goes farther, the change in the sun's position and schedule is 

 perceived; and awareness of this change is in direct proportion to the dis- 

 tance and velocity of movement. The farther and faster he goes, the more 

 keenly is he aware of the sun's changes relative to home. By the sun's arc, 

 one may tell whether he is north (arc lower) or south (arc higher) of 

 home. By its schedule, as measured against his clock or, more crudely, by 

 his metabolic stimuli, he must know the degree of his displacement east 

 (breakfast late by sun time) or west (breakfast early). By these cues a man, 

 suddenly shifted several hundred miles from his native range, might deduce 

 the direction home even when in unfamiliar surroundings. 



160 



