NO. 2298. 



THE GUANO BIRDS OF PERV—COEER. 



489 



sionally compel the brooding birds to seek the shores to rid them- 

 selves of the pests, as far as possible, by splashing in the water. 



Birds are often seen coming to the nests with feathers between 

 the jaws, or with pouch hanging low with small feathers or trash, 

 which is ejected with some difficulty and deposited by the side of 

 the mate to add to the lining of the nest. 



The nests, as observed, were shallow and roughly lined with 

 feathers and usually contained many small rocks. They contain a 

 variable number of eggs — from 1 to 8; 3 is the most common num- 

 ber. Of 207 nests counted 35 contained 1 egg; 73 contained 2 eggs; 

 84 contained 3 eggs; 10 contained 4 eggs; 4 contained 5 eggs; 1 con- 

 tained 6 eggs. 



Most of these were not new nests, so that the number of eggs was 

 probably permanent, barring accident or intrusion. In looking over 

 a large number of nests I saw two with 8 eggs each; from one of these 

 the eggs were opened and all contained live embryos of approxi- 

 mately the same size. A ninnber of nests with 6 eggs were seen, 

 whUe 5 was a very common number. Four nests, each with 1 egg 

 apparently old, were marked; 6 days later, they were as at first. 

 Three nests, each with 1 white (new-laid) egg, were marked (Nov. 29) ; 

 2 days later they were unchanged, but after 6 days one had 3, another 

 still one, and the third was empty. Of 7 other nests marked, one 

 with 2 white eggs gained 1, while 1 with 3 eggs lost all. Loss of 

 eggs may occu;r from the depredations of th« gulls or gallinazos 

 (turkey vultures); from the awkwardness of the parents causing 

 eggs to be thrown from the nest when the birds start in flight; and, 

 doubtless too, from pilfering by stray cats that, unfortunately, 

 infest the island. 



The eggs when new-laid are pure white in color, but soon become 

 30 soiled with guano as not to appear white at all. The form is 

 variable, and the ends are sometimes almost equal. The size is 

 about 82 mm. in length by 56 in transverse diameter and a little 

 less than 5 ounces in weight. The length of 10 taken at random was 

 from 76 to 97 mm.; transverse diameter, from 53 to 62; weight, 

 4 to 7 ounces, as shown by the following table. The egg of 97 mm. 

 in length and weight 7 ounces was a very exceptional one. 



Dimensions and weight of 10 eggs of Pelecanus ihagus, Lohos de Afuera. 



