WEST 



FOLK: I have two points to make; one is, we are equally sur- 

 prised to find a large quantity of fat in hibernating ground squirrels 

 after 4 months of hibernation. Not all animals, but some are very 

 conspicuously fat in spite of the fact that they awaken periodically. 

 This matches Dr. Irving's observations on birds. The second ques- 

 tion is a technical one. In measuring the oxygen consumption of the 

 evening grosbeaks you described a 3-day run with a hood on the 

 cage. Do you continue a photo-period during this period? 



WEST: Yes. 



FOLK; And what is the photo- period? 



WEST: Ten hours of light. We use a lucite cover with a loose 

 polyvinyl plastic cylinder taped to it that slides down over the 

 cylindrical cage and is sealed to the sides of the cage with electrical 

 tape. An outlet is provided at the top where air is pumped out into 

 the oxygen analyzer. An inlet is provided at the base of the cage. 

 These cages are identical with the cages we use for acclimation or 

 for housing the birds, and so we just have to drop the hood over 

 them. I think there is a lot to this psychological business. They do 

 not have to adjust to a new cage. 



IRVING: I have seen calculations on fat and tried to make some 

 myself to indicate that a gram of fat will transport a 20 gram bird 

 quite a long distance; the several grams that they have is adequate 

 for quite a considerable extra expenditure of metabolic energy, but 

 how about the requirement for water? I have not seen reference to 

 any visible reserve for water. 



WEST: You mean birds migrating over the ocean? 



IRVING: Yes. I wonder how they hold out. 



WEST: You do not think they get enough metabolic water? 



IRVING: I do not know. Can you calculate the water require- 

 ments and relate them to stores? 



WEST: I have not done so. 



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