342 NORTH AMERICAN BIRDS. 



finally been warmly lined with soft dry grasses and the feathers and down 

 of ducks and geese. This trustful pair seemed to know no fear. The 

 narrator often stood on a log to watch them, with his face so near that 

 their feathers frequently brushed against it as they toiled at their work. 

 Soon the nest was completed. Five eggs were laid, which were never left 

 once uncovered until they were hatched, the female sitting the greater part 

 of the time. They were fed with great assiduity by the parents, and grew 

 rapidly. In leaving the nest, two of the young birds fell to the ground, but 

 were picked up by the blacksmith, and placed with the others on their 

 roosting-place. A few days' training taught them the use of their wings, 

 and they soon after took their departure. 



Professor Eeinhardt records its occurrence in Greenland, at Fiskenaesset 

 and at Nenontalik. 



The natural breeding-places of these birds, before the settlement of the 

 country, were caves, overhanging rocky cliffs, and similar localities. Swal- 

 low Cave, at Nahant, was once a favorite place of resort, and in the unsettled 

 portions of the country they are only found in such situations. As the 

 country is settled they forsake these places for the buildings of the farm, 

 and their numbers rapidly increase. In the fur countries and in all the 

 Pacific coast, they still breed in and inhabit caves, chiefiy among limestone 

 rocks. 



Where the opportunity offers, they prefer to place their nests on the hori- 

 zontal rafters of barns. Built in this situation, the nests have an average 

 height and a breadth of about five inches. The cavity is two inches deep 

 and three inches wide, at the rim. The nests are constructed of distinct 

 layers of mud, from ten to twelve in number, and each separated by strata 

 of fine dry grasses. These layers are each made up of small pellets of mud, 

 that have been worked over by the birds and placed one by one in juxtaposi- 

 tion until each layer is complete. These mud walls are an inch in thickness. 

 When they are completed, they are warmly stuffed with fine soft grasses 

 and lined with downy feathers. When built against the side of a house, a 

 strong foundation of mud is first constructed, upon wliicli the nest is erected. 

 In this case the nest is much more elongate in shape and more strongly 

 made. 



A striking peculiarity of these nests is frequentl}^ an extra platform, built 

 against, but distinct from the nest itself, designed as a roosting-place for 

 the parents, .used by one during incubation at night or when not engaged in 

 procuring food, and l)y both when the young are large enough to occupy the 

 whole nest. One of these I found to be a separate structure from the nest, 

 but of similar materials, tliree inches in length and one and a half in breadth. 

 This nest had been for several years occupied by the same pair, though none 

 of their offspring ever returned to the same roof to breed in their turn. Yet 

 in some instances as many as fifty pairs have been known to occupy the 

 rafters of the same barn. 



