It is worth noting that the male alone is ornamented, the colours of the female being much plainer. This dates from a time when it was necessary for the female to be concealed while sitting on the eggs. The young of both sexes are coloured like their mother, the young males not acquiring the black gorget until perfectly able to take care of themselves. About the plumage there are some interesting facts. The young bird moults twice before the first winter. The second moult brings out the mark on the throat, but it is rusty now, not black in colour; his cravat is grayish and the wing bar ashy. In the spring, however, a noticeable change takes place, but neither by the moulting nor the coming in of plumage. The shaded edges of the feathers become brittle and break off, bringing out the true colours and making them clear and brilliant. The waistcoat is brushed until it is black and glossy, the cravat becomes immaculate, and the wristband or wing bar clears up until it is pure white. The homes of these sparrows are generally composed of a great mass of straw and feathers, with the nest in the centre; but the spotted eggs, perhaps, show that these birds once built open nests, the dots and marks on the eggs being of use in concealing their conspicuous white ground. Something seems already to have hinted to Nature that this protection is no longer necessary, and we often find eggs almost white, like those of woodpeckers and owls, which nest in dark places. We have all heard of birds flocking together for some mutual benefit--the crows, for instance, which travel every winter day across country to favourite "roosts." In the heart of a city we can often study this same phenomenon of birds gathering together in great flocks. In New York City, on One Hundred and Twenty-fifth Street, there stands a tree--a solitary reminder of the forest which once covered all this paved land. To this, all winter long, the sparrows begin to flock about four or five o'clock in the afternoon. They come singly and in twos and threes until the bare limbs are black with them and there seems not room for another bird; but still they come, each new arrival diving into the mass of birds and causing a local commotion. By seven o'clock there are hundreds of English sparrows perching in this one tree. At daylight they are off again, whirring away by scores, and in a few minutes the tree is silent and empty. The same habit is to be seen in many other cities and towns, for thus the birds gain mutual warmth.