168 BULLETIN J.9i, UNJTLD S1AT1:S NATIONAL MUSEUM 



The cries of the young birds were accompanied by energetic flapping 

 of the wings. The white on the wings helped to make the birds con- 

 spicuous while thus flapping, so that chances for the attention of the 

 approaching bird being directed to them were increased. This may be 

 an important function of this set of white markings. Whether developed 

 because of its adaptive value or not, it certainly operates to disclose the 

 locations of the young birds to the human observer and presumably like- 

 wise to the parent birds when they are approaching with food. 



The brood of young magpies, being separated and in different trees, 

 gave a good opportunity to see additional features of the response of 

 parents to begging young. The destination of the approaching parent 

 seemed to be controlled entirely by the amount of commotion made by 

 the young. The group that began calling first and kept it up with 

 greatest vigor was the one finally approached. Sometimes a parent 

 abruptly changed its course when headed toward one group and went 

 to another, apparently because of a greater persistence in begging there. 

 Once, when an adult started to leave, it was attracted by calls from an- 

 other group and turned back and went there. It was not determined 

 whether any food was delivered to the second group. 



The young magpies showed little ability to distinguish their own 

 parents. Any magpie flying toward them aroused the cries and wing 

 flapping. These ceased, however, as soon as the flying bird passed 

 and took a course away from the young birds. Once the young birds 

 begged when a California woodpecjcer flew over them. The amount 

 of begging seemed to be a direct expression of the degree of hunger. 

 Apparently the two young that stayed at the nest were not yet able to 

 fly. The others could fly; hence they probably were larger and pos- 

 sibly they required more food than the ones at the nest. At least more 

 trips were made to them by the parents. But the ones at the nest were 

 not neglected. For a few trips after food was taken to the nest, the 

 young ones there would remain almost quiet, giving only one or' two 

 notes during each visit. 



When a parent landed in some tree other than the one holding the 

 young birds, they would fly to that place, flap their wings, make loud 

 calls, and attempt to get in front of the adult. The latter did not 

 remain long after food was placed in the widely opened mouth of some 

 one of the youngsters. Each parent, in turn, left and went to the 

 nearby orchard to obtain another supply of food. The trips were about 

 five minutes apart. The adults generally were quiet, but occasionally 

 they uttered series of alarm notes, usually when awav from the voun? 

 ones. ' ^ ^ 



Between feedings the young magpies moved about on the limbs of the 



