Named after true swallows (Hirundinidae) because of their aerial-feeding habits, the woodswallows differ from that family in many respects, and the two groups are totally unrelated. In contrast to the slim swallows with their tiny bills, long wings and forked tails, woodswallows are stocky or “chunky” birds with thick, almost conical blue-grey bills, shortish and distinctly triangular-shaped wings and relatively short, square-cut tails. Moreover this small family of 11 species is mainly restricted to Australasia, where it presumable arose, although one or more forms obviously crossed Wallace’s Line to the west, and one species is now confined to the Asian mainland. Although woodswallows capture most of their insect prey on the wing, either while circling high in the sky or during dashing sorties from an exposed perch, they will also dive onto the ground, especially when prolonged windy conditions prevent insects from flying. In addition, many Australian species regularly feed on floral nectar, facilitated by their brush-tipped tongues. Woodswallows are highly social and flocks can be seen huddling together, side-by-side, on a wire or branch, during both the day and night. One species occurs in Java.
Flight: Agile, aerobatic. Fast shallow wing beats, interspersed with short glides while feeding; long glides when soaring on thermals.
Among the most successful of all songbird families, the Corvidae comprise 123 species that are spread throughout the world, many of which have adapted so well to man-made habitats that they have become commensals of humans, and are considered pests in some densely-populated cities. Famous as a group for their intelligence, several forest species are known to manufacture and use stick “tools” to reach inaccessible prey, while one city-dwelling species has learnt to take advantage of cars on busy streets to crush nuts, as well as to avoid being crushed themselves by using pedestrian crossings! Most members of the family are medium to large in size, and have stout bills with a characteristic tuft of bristles that extends to the nostril openings, as well as long, powerful legs. Whilst crows are predominantly black in plumage, many of the jays and magpies are very colourful. Omnivorous and supremely opportunistic, they eat anything from invertebrates and vertebrates of all kinds, including small mammals, bird nestlings, and carrion, to fruits and nectar. In cities and villages, they are best known as scavengers of human refuse. Social organization is varied among members of the family, but most species are gregarious, and some form communal roosts containing thousands of birds. Calls are similarly variable among species, some having over 20 different calls each use in different contexts, and ranging from guttural squawks to melodious songs. Nests tend to be bulky stick platforms.
Six members of this family occur in Java, of which one is introduced (House Crow); three native species are found in Baluran.