118 BIRDS' NESTS 



the Solomon Islands. The most remarkable feature 

 in these exceedingly curious birds is the bill, which is 

 furnished with a more or less developed casque. 

 Little less remarkable is the manner of their repro- 

 duction. These birds breed in holes in trees,^ select- 

 ing one ready made for their purpose, and depositing 

 a single white egg on the powdered wood at the 

 bottom. So far all is perfectly normal, but now the 

 most extraordinary part of the business begins. As 

 soon as the hen bird commences to incubate, the cock 

 makes her a prisoner by plastering up the entrance 

 with mud, leaving, however, a small hole through 

 which he faithfully supplies her with food. Our 

 next group of hole nesters consists of the Toucans 

 (Rhamphastidas), numbering about sixty species, and 

 confined to South America and Central America as 

 far north as Mexico. The most striking feature in 

 these birds is the remarkably large and often beauti- 

 fully coloured bill, out of all proportion to the size 

 of the body. Toucans are forest birds, and, like the 

 Hornbills, select a suitable hole in some tree in which 

 to deposit their white eggs, for which no other pro- 

 vision is made. Another group of exquisitely beautiful 

 birds nesting in a similar manner is the Trogons 

 (Trogonidae). These birds are dwellers in the equa- 

 torial forests right round the world, and all of them, 



^ The Ground Hornbill {Bucorvus abyssinicus) is said to build a 

 large nest of sticks in a tree standing alone {conf. Ibis, 1897, 

 p. 422). 



