Because such feathers keep the body of the bird warm and dry, by repelling the water from their surface. A bird could scarcely move through the water, with the downy feathers of the ostrich, because of the amount of water the down would absorb.
1034. Why is man born without a covering?
Because man is the only animal that can clothe itself. As in the various pursuits of life he wanders to every part of the globe, he can adapt himself to all climates and to any season.
"Who teacheth us more than the beasts of the earth, and maketh us wiser than the fowls of heaven?"—Job xxxv.
1035. Why do the furs of animals become thicker in the winter than in the summer?
Because the creator has thus provided for the preservation of the warmth of the animals during the cold months of winter.
1036. Why does a black down grow under the feathers of birds as winter approaches?
Because the down is a non-conductor of heat, and black the warmest colour. It is therefore best adapted to keep in their bodily warmth during the cold of winter.