AWARENESS OF TIME AND SPACE 



Canada Geese, like Mallards, go to stubble each morning, but unlike 

 these ducks they do not respond to the sharp division between night and 

 dawn. The big honkers usually remain on their night roost until the sky is 

 bright and the details of the landscape are well lighted. Some keep a routine 

 that does not take them to the fields until after sunup. Nevertheless, they 

 are regular in their delayed breakfast travel; if the weather remains con- 

 stant they are seen on the way to the fields at about the same time each 

 morning. For a week in early October I watched a group of Canada Geese 

 leave the lake every day between 6:45 and 7:00 a.m. Another flock crossed 

 Slack's field daily within a few minutes of 8:00 a.m. Geese must be hungry 

 at dawn, and several morning birds I have shot on the out-flight had empty 

 gizzards. It is neither dawn-light nor hunger by which the time of their 

 departure is regulated. Somehow they must be aware of intervals of time. 

 That such awareness of time must exist seems evident in the pioneering 

 studies of Gustav Kramer (1951, 1952). His work suggests that birds do, 

 indeed, appreciate intervals of daytime on the basis of the sun's position 

 and the angle-speed of its movement — a perception of periods of time be- 

 tween sunrise and sunset. Canada Geese measure the interval between 

 dawn and that point of the morning when they fly out to feed. A similar per- 

 ception of interval was noted for bees by von Frisch ( 1950:78), who tells us 

 that "bees have a good memory for time. If one feeds them at a certain spot 

 for a few days between ten and twelve o'clock, they visit this spot for the 

 next few days from ten to twelve even though the food dish is empty." 



Many other birds go out to feed on regular schedules. The autumn marsh 

 is the roosting place for Redwings and other blackbirds that launch forth 

 to the farmland at the same time each morning. The blackbirds, however, 

 hold to their roosts while the Mallards are outbound, and it is three-quarters 

 of an hour after the first duck flights that they leave for breakfast. Next 

 come the Herring Gulls, forewarning the goose hunter to keep his eye on 

 the horizon for the first sight of Canada Geese. Seibert (1951), who studied 

 the feeding flights of herons, observed that the "time of sunset and sunrise 

 was found to be the most important factor controlling the arrival and de- 

 parture of all species." Nice (1935) watched the regular morning move- 

 ments of Starlings and Bronzed Grackles and found that the "first Starlings 

 left the roost at lower light values than did the Grackles . . ." At Delta the 

 small Richardson's Geese regularly depart for the fields earlier than the 

 Canada Geese; they are often shot during the dawn flight of Mallards, 

 while Canadas are seldom killed on farmland so early as dawn. 



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