BARN SWALLOW 447 



times delay laying in it for two weeks after it is finished. They seem 

 to prefer to repair and use an old nest rather than build a new one, 

 so that often the same nest is occupied for a number of years, or a 

 new one is built on the remains of the old one, or at least in exactly 

 the same spot. 



The size and shape of the nest vary greatly with its location; 

 on a vertical surface the nest is roughly in the shape of a reversed 

 half cone, the top being somewhat more than half a ciTcle, and the 

 lower end pointed; if bnilt on a flat surface, the nest is more circular, 

 like a phoebe's nest, and much shallower than the cone-shaped nests, 

 but in such cases the birds often build mud walls along the flat beam 

 for a foot or more, apparently for perches or to prevent the young 

 from falling while exercising their wings. Nests built in corners 

 or in the angles of braces are smaller and made to fit the spaces. 

 The outer diameter of the circular top of the nest will average about 

 5 inches and the inner diameter is, fairly constantly, about 3 inches. 



The composition of the nest consists mainly of dried mud mixed 

 with grass and straws, and it is profusely lined with poultry feath- 

 ers, mainly white ones. A nest dissected by Dr. Wood (1937b) "was 

 found to contain, besides nearly seven and one-half ounces of dried 

 earth, 1635 rootlets over one-half inch in length, 139 white pine 

 needles, 450 pieces of dried grass, 10 chicken feathers, 4 pieces of 

 wood, 2 human hairs and a piece of leaf and cotton, and a table- 

 spoonful of minute pieces of rootlets and gi-ass." 



Horse hairs enter into the composition of many nests. Dr. Dickey 

 tells me that he has seen swallows hover around stalls and disentagle 

 the hairs lodged in cracks; these hairs sometimes make trouble for 

 the birds. 



Some nests are made without the use of mud; nests in naiTow 

 crannies or holes, with supporting floor and sides, do not need the 

 mud foundation and are made of grasses, straws, feathers, and other 

 available materials, James B. Dixon says in his notes: "The nests 

 in the caves of the ocean walls are very unusual in that the birds 

 are hard pressed for suitable mud and use a great deal of sea weed, 

 with the results that the nests look like some old man with a beard, 

 as the sea weed stringers hang down from the nest." These nests 

 are lined with seaweed instead of feathers. 



Eggs. — The barn swallow's set usually consists of four or five eggs ; 

 six eggs are fairly common, and seven are rare; as many as nine have 

 been found in a nest, but these were probably the product of two 

 females. The eggs are practically indistinguishable from those of 

 the cliff swallow. They vary from ovate, the commonest shape, to 

 elliptical-ovate, or rarely to elongate-ovate. The ground color is 

 white, and the markings are in shades of bright reddish brown or 



