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 (Momotide). In these showy birds the sexes 
are exactly alike, and the nest in a hole under ground. 
3. Puffbirds (Bucconide). 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 (Trogonide). In these magnificent birds the 
females are generally less brightly coloured than the males, but 
are yet often gayand conspicuous. The nest is in a hole ofa tree. 
5. Hoopoes (Upupide). 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 (Bucerotide). 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 (Capitonide). 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 (Rhamphastide). 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 (Musophagide). 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 (Picide). 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. 
