YELLOW-BILLED MAGPIE 159 



the female flew down to join the group, but there was no more fight- 

 ing. Next time, when the same three birds were on the ground directly 

 under the nest, the brooding female flew toward them with many ex- 

 cited calls. 



On another occasion the four birds from two nests in trees at opposite 

 ends of a barn were together for about 5 minutes at one corner of the 

 barn. Their loud calls indicated excitement. One, with raised tail, 

 quivered its wings slightly, possibly indicating an early stage in the 

 hegging which the females develop. Then there was fighting in which 

 all four birds took part, but which led to no decisive conclusion. Finally 

 one took a stick to one nest, and its mate tried to carry one that was 

 too heavy, so it went to the nest with no load. Both birds of the other 

 pair then went to their nest. The purpose of the fight was obscure; 

 possibly there was no immediate purpose, but only an indistinct urge to 

 fight. 



Study of numerous examples such as have been recounted brings the 

 conclusion that the accounts reported so often as examples of courtship 

 and pairing in the European magpie may have been encounters between 

 groups of birds already paired. The pursuits could have been merely 

 attempts to drive away intruders. And the congregation of small assem- 

 blies of excited birds could have been exhibitions of the common magpie 

 trait of hurrying to investigate any disturbance. Also the reported ex- 

 amples have occurred too late in the nesting season to expect them to 

 represent the very earliest stage of nesting. Recent observations indi- 

 cate that pairs are well established in fall and that spring is the season 

 for noisy squabbles incident to competition for nest sites or indicators 

 of jealousy toward intruders. Until marked individuals can be traced 

 through the whole cycle, it is not justifiable to consider this interpreta- 

 tion as conclusively established, but it now seems more reasonable than 

 the traditional one. 



There are other segments in the series of actions that amount almost 

 to preparation for the behavior to come in the incubation period, and 

 these are to be observed before, through, and after the period of nest 

 building. Even though the birds are seen oftenest in small groups or 

 flocks, it is probable that the units in the organization are pairs that 

 remain together throughout the year. During and after the long period 

 of nest building, or reconstruction, a large share of the time is spent at 

 or near the nest. The two birds of each pair spend several hours of 

 each fair day perched side by side on some limb close to the site. At 

 such times one of them often utters a song that I have been able to hear 

 as far away as 100 yards. There are other indications that during this 

 preincubation time a magpie's attention is largely centered about its 

 nest and its mate. 



