WESTERN ROBIN 63 



robins were seen on the Jordan Hall east lawn. The newcomers may have been 

 previously feeding on berries in the nearby oval and moved to the lawn when the 

 berries were exhausted. Many of the newcomers were in White-head's territory 

 and it was very vigorous in combating them. During a three-minute interval in 

 the late afternoon it was observed to combat ten times. Usually the opponent 

 would retreat a short distance as soon as White-head rushed at it; sometimes both 

 flew up in combat; but in every case White-head was successful. In a few days 

 the number of robins on the Jordan Hall east lawn was once more only about a 

 dozen. 



His experience with the other robin, "White-tail," was similar. It 

 was not observed until February 12 but may have been there before 

 that; it had a smaller territory, about 300 square yards; it was driven 

 out of another small lawn that was being defended by a normal robin 

 and forced to return to its own territory. 



Howard L. Cogswell, of Pasadena, Calif., writes to me: "Over 

 much of the valley area robins flock with cedar waxwings, which seem 

 to prefer much the same food; a dozen or so robins to a hundred 

 waxwings is about the usual proportioD. In some localities, though, 

 there are regular robin roosts. One such in a eucalyptus grove at 

 the base of the Santa Monica Mountains, near North Hollywood, 

 was frequented by hundreds of birds each night during the winter of 

 1940-41, according to my friend Arthur Berry. On December 27, 

 1942, when I visited this spot at dusk, small flocks of robins came 

 flying over at a height of about 250 feet. As they were directly over 

 the trees, several groups half closed their wings and tumbled precipi- 

 tously into the thickest of the topmost branches, immediately ceasirjg 

 their call notes, which had been given by the whole flock flying over." 



Dr. Helmuth O. Wagner tells me that the robins from the north 

 arrive in the vicinity of Mexico City during the first part of October, 

 mostly in flocks of 10 to 30 birds. They frequent the bushy forests 

 of oaks, pines, and cypresses, preferring the open forests. The flocks 

 are not compact, and, if they are frightened, one after another of the 

 birds flies away. Sometimes, they are in berry-bearing trees, to- 

 gether with Ptilogonys cinereus, which are living in fixed flocks and 

 are coming to the same trees for berries. In December, or later, if it 

 is very dry, you will see more single birds, or flocks of three or four, 

 in the cornfields near the borders of the forests, looking for insects or 

 other food. At all times they are very shy, and if they see anyone 

 they fly into the bushes on the borders, or into the high pines of the 

 forests. So far as it is possible to identify them, the same flocks 

 remain all winter within a fixed area. In the summer of 1935 he 

 observed a flock of 10 birds, more or less, in a forest of pines and liquid- 

 ambar at 1,700 meters in the mountains of Chiapas. 



