6 The Wilson Bulletin — No. 58. 



that the nest proper is sometimes phiced in a cavity. The 

 nests I have found were all placed in birch trees, but of course 

 numerous other kinds of trees and even elder and juniper 

 bushes are used. One side of the nest leans against the body 

 of the tree, the bottom resting upon a bough and fastened 

 to it. 



It is a delight to watch the birds building their domicile. They 

 begin by placing a number of mosses and lichens on the 

 bough, perhaps to the extent of four or five centimeters, 

 carrying the material with their tiny bills, and making trips at 

 regular intervals, never going very far away from the home- 

 place. They securely fasten the material with larger pieces, 

 then build upon this, clinging the while to the outside walls 

 with their tiny feet, thus working away until they have felted 

 an oval-shaped ball fifteen or twenty centimeters in height and 

 probably eleven or twelve centimeters in circumference. They 

 line the inside with feathers, wool, and horse-hair, leaving a 

 round entrance hole a trifle above the center of the ball. The 

 outside of this wonderful piece of workmanship, which it 

 takes about three weeks to complete, is so closely covered with 

 lichens, spider-webs and the like, that it cannot be dis- 

 tinguished with certainty from many a knot with which the 

 branches are covered. One must therefore resort to the 

 practice of watching the female as she goes to and from the 

 nest. Some writers assert that the entrance to the nest is al- 

 Avays on the east side but I must confess that this is a point 

 that has escaped me. 



The Long-tailed Tit is very prolific, as many as 17 eggs 

 having been found in a nest, while I have always found ten. 

 Eggs in my collection from Holland show about the average 

 measurement of 14 by 10 millimeters. 



Nest building comes in April. I found ten young ready to 

 fly on May 18, 1890 (see Wm. Baer, Ornis der preussiscben 

 Oberlausitz, page 31). Incubation lasts about 13 days. The 

 young are fed with great regularity about every five minutes 

 with a great variety of insects, insect eggs, and larvae, When 

 older thev stick their long tails through the walls of the nest. 



