6 Bird - Lore 



up any small portions from the bare floor that may have been broken or detached, 

 and in the manner as described caulking it into any little space offering, work- 

 ing from the bottom up, always below the top rim, upon which nothing is laid 

 after the walls are raised to a level with the floor of the nest proper and the 

 threshhold of the opening. The walls are then raised on all sides by forcing 

 the building material into the wall from below in such a way as to act as a wedge. 

 The mouthful of material is pushed awl-like into the wall, raising its upper 

 edge, until its proper place is attained and it is released from the mandible. 

 Then the ends and loose parts are tucked in in like manner, not as a pellet, 



DIPPER'S NEST WITH YOUNG 

 Photographed by H. W. Nash, at Sweetwater lake, Colo., July 20, 1897 



but rather suggesting a plug resembling a spider. The sprays and fibers on the 

 outside are allowed to lie loose, plush-like, to lead the water from the dome roof 

 as from a hay-cock. As this work on the walls dries the insertion of other plugs 

 with their outrigging, so to speak, knits the whole densely. These insertions 

 necessarily act forcibly on all sides, the limit of the little worker's strength, 

 fully sufficient for the work in hand, seeming to be used. I noticed that the part 

 of the wall she was working upon was about three and one-third inches high, 

 and while she was working in the material about one and one-half or two inches 

 from the floor (which was on an incline of one and one-half inches in seven 

 inches, the lowest part being in front and to one side, upon which side she was 



