P. 278 -Continued- California Condor. Eben McMullan 21 August 1963 Food site Flight Thinking body weight. going out to hunt for food again. To some of this thinking, I would agree. Probably the relationship between the body weight of a bird and its ability to fly is quite critical. It is known that birds will become unable to fly whenever the body fats increase to body weight above a certain degree. Under certain conditions I have observed condor having difficulty flying. Other observers have found condor unable to fly due to what they felt was conditions preventing them from doing that in the matter of several hours would and the bird be able to again sustain itself in flight. It has been held by many old settlers of the Condor Country that Condor will eat so much that they cannot fly from the ground. If any, or all of these instances are correct it would go with saying that the body weight and ability to fly relationship in Condor is probably more critical than in nearly any other land bird that depends on sustained flight over great distances, as a means of survival. Therefore it would seem natural that Condor would have an inherent mechanism that would work as a governing force to prevent these birds from eating so much that the body weight would reach that whereby it would interfere with their ability to fly. This may help explain Mr. Calhoun's query as to why Condors are seen passing his lookout two or three days in row then several days will lapse before Condor are seen again. This also could explain why Condor movements the Narajo Valley and San Juan River were so sporadic this spring, even though the food supply was abundant at all times. This may also explain Mrs. Evelyn Farmsworth's query why Condor always come to feed on dead calves as soon as the calfers commence calving, but that after a few days they leave and are not seen again for some time even though much would be available to Condor, so long as the cows and heifers continue to drop calves which usually lasts for about 5