INTRODUCTION. 
xlv 
porated and blended with mud. The construction of the hemispheric nest of 
the Martinis, while it continues, a w^ork of severe labor and toil ; as soon as 
the morning appears, the old ones mutually prepare to erect it. After the birds 
have fixed on a situation, they endeavour to lay a foundation, on wdiich to 
rear the curious superstructure. This, in general, is an object obtained with 
difficulty : and they will sometimes erect many little lines of foundation, and 
desert them. They commonly raise two layers in a day; one in the morning, 
and the other in the evening ; so that sufficient time may intervene to indu- 
rate the materials, and render them tit to support the weight of succeeding 
depositions. They begin the nest on the outside, clinging in a perpendicular 
posture to the w^all, until the layers are sufficiently high to wmrk upon from 
within. They then enter, and fixing their tails against the wall, they 
become the centre of their motions, and thus they readily form a semicircle 
around. They use their bills, for placing the materials in order, and 
oftentimes their diin, for compressing them together. Each layer, at first, 
consists of about one-sixth of an inch in thickness, until they are enabled to 
work on the inside, and then they raise deeper ones, and more extended, from 
one-third to half an inchin thickness, and sometimes even more ; and twm 
of these layers are frequently raised in a day : but the foundation alone is 
sometimes a work of many days, as they are often obliged to stud the wall 
along for many feet, before they are satisfied with its durability. Some- 
times they appear to be actuated by more than common activity ; at other 
times they raise but a slight deposition, and employ themselves but a short 
period in their labours. The materials used externally are mud and bits 
of straw, or other slight substance to make it cohere; the former, if possible, 
is taken from the moist margin of a pond, or miry place ; but if the bird 
cannot procure materials thus ready for use, it selects a bit of dry mould, 
or clay, and flies to some neighbouring spring to wet it. This action is 
performed on the wing; it skims along just above the surface of the water, 
frequently dipping its little bill in the stream. At other times, wdien it can 
discover the materials prepared, it mingles them together with little pieces 
of straw, or grass, with its bill. Every particle, of which the structure 
