YiiLLOW-blLLliD MAGPIE 157 



Anotlier and more easily interpreted example was noted on the morn- 

 ing of November 12, 1937, when one of two magpies in a regularly 

 used blue-oak nesting tree was carrying a dead twig about 10 inches 

 long as it moved from branch to branch. At about the same hour the 

 next morning the two magpies were seen again in this tree and one 

 of them was carrying a 10-inch stick. A few seconds later there was 

 excited calling and then a pursuit flight round and round in the top of 

 the tree. Several magpies flew to the tree and joined in the chase. 



Fifteen minutes later two magpies flew into this blue oak and wiped 

 their bills on branches, apparently returning from a foraging expedi- 

 tion. After a few seconds they flew, together, downslope to where two 

 others were foraging, but when these flew up toward them and called, 

 the first two circled back and returned to the tree. Later they left to- 

 gether in another direction. This behavior surely indicates segregation 

 by pairs. 



After another return to the tree these two magpies flew down and 

 joined the two they had approached earlier. All four strutted about 

 with tails held high for a few minutes, and then the first two flew back 

 to the oak. 



Further evidence of segregation into pairs in fall was recorded on 

 November 18. Two birds were foraging in a stubble field and occa- 

 sionally flying up to fence posts. One took some food, probably a large 

 insect, to a post where the morsel was picked to pieces. When a person 

 approached the birds, one flew off to willows along the adjacent creek, 

 while the other, engrossed in its foraging, stayed a moment longer and 

 then flew off to an oak in the opposite direction. The two then called 

 to each other with several rattling calls, which were answered. Other 

 calls heard up and down the canyon indicated that magpies were scat- 

 tered over an area extending for several hundred yards. Several times 

 birds in flight were in pairs. 



In the afternoon two pairs were perched in a locust tree, the birds of 

 each pair sitting within a few inches of each other. Low, musical notes, 

 a primitive song, were heard. Both pairs flew oflf at about the same time. 

 Other magpies, also active and noisy in the vicinity, were flying from 

 one tree top to another, usually in pairs. Even when they started for the 

 roosting place in the evening, magpies on this day seemed still to be 

 segregated by pairs. Two birds started ofif across the canyon, fol- 

 lowed immediately by ten others from various points. These con- 

 verged until all were strung out in a single file along the same line of 

 flight. 



It is desirable to keep in mind, in considering these happenings, that 

 they took place before the start of winter, long before the start of nest- 



