vi A THEORY OF BIRDS' NESTS 125 



the same genus, the tail of the female is rufous, while that of 

 the male is blue. In most kingfishers the nest is in a deep 

 hole in the ground ; in Tanysiptera it is said to be a hole 

 in the nests of termites, or sometimes in crevices under over- 

 hanging rocks. 



2. Motmots (Momotidse). In these showy birds the sexes 

 are exactly alike, and the nest in a hole under ground. 



3. Puff-birds (Bucconidse). These birds are often gaily 

 coloured; some have coral -red bills; the sexes are exactly 

 alike, and the nest is in a hole in sloping ground. 



4. Trogons (Trogonidse). In these magnificent birds the 

 females are generally less brightly coloured than the males, but 

 are yet often gay and conspicuous. The nest is in a hole of a tree. 



5. Hoopoes (Upupidse). The barred plumage and long 

 crests of these birds render them conspicuous. The sexes are 

 exactly alike, and the nest is in a hollow tree. 



6. Hornbills (Bucerotidae). These large birds have enor- 

 mous coloured bills, which are generally quite as well coloured 

 and conspicuous in the females. Their nests are always in 

 hollow trees, where the female is entirely concealed. 



7. Barbets (Capitonidse). These birds are all very gaily- 

 coloured, and, what is remarkable, the most brilliant patches 

 of colour are disposed about the head and neck, and are very 

 conspicuous. The sexes are exactly alike, and the nest is in 

 a hole of a tree. 



8. Toucans (Rhamphastidae). These fine birds are coloured 

 in the most conspicuous parts of their body, especially on the 

 large bill, and on the upper and lower tail coverts, which are 

 crimson, white, or yellow. The sexes are exactly alike, and 

 they always build in a hollow tree. 



9. Plaintain-eaters (Musophagidae). Here again the head 

 and bill are most brilliantly coloured in both sexes, and the 

 nest is in a hole of a tree. 



10. Ground cuckoos (Centropus). These birds are often 

 of conspicuous colours, and are alike in both sexes. They 

 build a domed nest. 



11. Woodpeckers (Picidae). In this family the females 

 often differ from the males in having a yellow or white, 

 instead of a crimson crest, but are almost as conspicuous. 

 They all nest in holes in trees. 



