Pigeons digest their food with the aid of a secretion in the crop, and it is on this soft material, popularly known as "pigeons' milk," that they feed their nestlings. This method suggests analogy to that of the petrels, which rear their young on fish-oil partly digested after the same fashion. Indeed, all the pigeons are devoted parents. Though the majority build only a very pretentious platform of sticks for the two eggs, they sit very close and feed the young ones untiringly. Some of the pigeons of Australia, indeed, go even further. Not only do they build a much more substantial nest of leafy twigs, but the male bird actually sits throughout the day, such paternal sense of duty being all the more remarkable from the fact that these pigeons of the Antipodes usually lay but a single egg. Australia, with the neighbouring islands, must be a perfect paradise for pigeons, since about half of the species known to science occur in that region only. The wonga-wonga and bronze-wing and great fruit-pigeons are, like the "bald-pates" of Jamaica, all favourite birds with sportsmen, and some of the birds are far more brightly coloured than ours. It is, however, noticeable that even the gayest Queensland species, with wings shot with every prismatic hue, are dull-looking birds seen from above, and the late Dr. A. R. Wallace regarded this as affording protection against keen-eyed hawks on the forage. His ingenious theory receives support from the well-known fact that in many of the islands, where pigeons are even more plentiful, but where also hawks are few, the former wear bright clothes on their back as well. The woodpigeon has many names in rural England. That by which it is referred to in the foregoing notes is not, perhaps, the most satisfactory, since, with the possible exception of the smaller stock-dove, which lays its eggs in rabbit burrows, and the rock-dove, which nests in the cliffs, all the members of the family need trees, if only to roost and nest in. A more descriptive name is that of ringdove, easily explained by the white collar, but the bird is also known as cushat, queest, or even culver. The last-named, however, which will be familiar to readers of Tennyson, probably alludes specifically to the rock-dove, as it undoubtedly gave its name to Culver Cliff, a prominent landmark in the Isle of Wight, where these birds have at all times been sparingly in evidence.