NESTLINGS OF FOREST AND MARSH 
appeared to pick up as much as their mouths 
would hold, but whether they also filled 
their throats, as some aver, seemed doubtful 
to me. The only support I could find for 
this view was the shape and quantity of each 
pellet as seen in an old nest. Each one 
seemed to have a roundness and smoothness 
that would indicate a moulding in the throat. 
Also, some of the nests were so much harder 
and less crumbly than others, it would seem 
there might have been a difference in the 
saliva of the builders. The work of con- 
struction itself was most curious. Founda- 
tions were laid in as complete a circle as 
possible, and where no other nest or beam 
interfered the result was surprisingly perfect. 
On this foundation were placed the pellets of 
mud, like bricks on a wall but in ever narrow- 
ing circles, thus building out and up at the 
same time. Unlike the work of the robin or 
the wood thrush, the brick-laying of the swal- 
lows in every case observed was done from 
the outside, the bird spitting out the clay in 
a lump and patting it into place with his 
198 
