5. The rook.—Notice the size, shape, and colouration of the bird. Do rooks live merely in pairs or in large communities? Do they build on the ground or in trees? Are the trees high or low? What is the largest number of rooks’ nests you have seen in one tree? Watch the birds repairing and building nests in February and March. Of what are the nests composed? Have you ever seen rooks stealing sticks from other rooks’ nests? Are the birds quarrelsome? Where do they feed? Do they hop or walk? Do they keep together when feeding? Do all the birds of one rookery feed at the same time, or do some remain in the trees? Why? What is the shape of the beak? How is this associated with the food of the bird? Do the farmers in your neighbourhood consider rooks useful or the reverse? Why? What is the voice of the rook like? How does it vary to express warning, anger, etc. Describe any observations which lead you to suppose that a colony of rooks has a code of laws. Describe the flight of the rook; what other birds fly in a somewhat similar manner? In spring, look beneath the trees for the broken shells of eggs which may have fallen from the nests. What is their colour? Describe the appearance and habits of the young birds. Where do rooks spend the winter? Have you ever seen them visiting and inspecting their nests in winter? 6. Other birds of the crow family.—With the rook compare and contrast the crow, raven, jackdaw, magpie, and jay. [Pg 313] The swallow family.—Swallows and martins are popular with all lovers of birds, for many reasons. Their arrival is welcomed as visible evidence of the approach of summer; their graceful and rapid flight delights the eye; their obvious liking for the neighbourhood of human dwellings wins our sympathy; and, lastly, they claim our gratitude by their incalculable services in keeping down insect pests. The swallow (Fig. 202) may readily be distinguished from the martins by the absence of white from its upper parts, which are glossy and of a steel-blue colour. The forehead, chin, and throat are of a pink or chestnut colour; the ventral surface is white, with a black band crossing the neck. The tail is long, and very deeply forked. The bill is short and broad, and the gape stretches nearly to the eyes—a great advantage to a bird living on insects which are caught flying. The feet are very small and weak, but as the swallow spends most of its time in the air, and rarely alights on the ground except to collect materials for its nest, it does not need very sturdy hind-limbs, and the feet are chiefly used for perching. Fig. 202.—The Swallow. (× ¼.)