YELLOW-BILLED MAGPIE 171 



a habit regularly noted. During a period of warm sunshine on a Janu- 

 ary afternoon, magpies were making flights out and up from a dead 

 oak on a knoll, presumably after insects. The flights ranged in length 

 from 15 to 50 feet. At the end of each one the bird generally swooped 

 and zigzagged up and down as if in pursuit of an insect. Return was 

 to the same dead oak. Similar behavior was noted in the fall. 



Another habit, characteristic of foraging magpies, is to search under 

 objects such as chips of wood or cow dung. These sites are hiding 

 places for a great variety of insects and other invertebrate animals. 

 They are generally inaccessible to most foraging birds, which are too 

 weak to uncover them, but magpies can get them with slight incon- 

 venience. In addition, from the heaps of dung they often get grain. 



Magpies keep a close watdi for new food sources. They quickly find 

 scraps of waste about houses, such as garbage or bits of food that may 

 be thrown out on the ground. They watch other feeding animals, birds 

 or mammals, and rush to retrieve any bit of food that may be lost or 

 discarded. Other foraging magpies even are watched closely, and many 

 pursuits occur when one attempts to carry some item of food. Any ob- 

 ject too large to be swallowed immediately or to be carried away is 

 likely to be the center of a contest so long as any of it remains. These 

 encounters rarely reach the stage of actual combat. 



To force others away from food, the magpies use a posture as a sort 

 of bluff. Both parties in such a dispute stand very high, point their bills 

 upward at nearly a 70° angle, throw out the breast and throat, and work 

 the muscles as if producing calls. If any are made, they are inaudible 

 to a person 50 feet away. The successful bluffer then walks toward the 

 other bird as if to bump his chest against the other. This sometimes 

 occurs, but oftener the gesture is sufficient to retire the opponent. This 

 pose seems to leave its maker in extremely vulnerable position with 

 sensitive throat exposed to attack, but no blows have been seen struck 

 there. The retiring bird crouches down and shrinks aside, still holding 

 its bill up. 



Sometimes a bird resorts to blows instead of bluff when another be- 

 comes too persistent. Then a swift hop and peck at the head of the 

 intruder drives it off. So long as the other birds do not try to feed, they 

 are permitted to stand so close to the feeding bird as to bump it occa- 

 sionally. When pursuits occur, they may be only for about twelve inches, 

 but in the interval an onlooker usually takes possession, and frequently 

 it then refuses to be driven away. 



Some individuals merely wait their turn to feed. Occasionally one 

 watches for a long time and then suddenly forces away the possessor. 

 It may be that this period of watching serves to build up courage. Some 



