Squacco heron
Ardeola ralloides
SUBFAMILY
Ardeinae
TAXONOMY
Ardea ralloides Scopoli, 1769, Carniola. Monotypic.
OTHER COMMON NAMES
French: Crabier chevelu; German: Rallenreiher; Spanish: Garcilla Cangrejera.
PHYSICAL CHARACTERISTICS
Tawny buff brown with a streaked head, crest, and back, and light belly. Length is 16.5–18.5 in (42–47 cm); weight is 8–13 oz (230–370 g). In breeding it develops a distinctive black and white mane. Immature birds are similar to adults in nonbreeding plumage, but drabber and lack crest and back plumes.
DISTRIBUTION
Occurs in Europe, Africa, Madagascar, and the Middle East to Iran.
HABITAT
Occurs in dense marshes—shallow fresh water with a cover of reeds and dense bushes. Its principal habitat throughout its range is now rice fields. It also occurs in ponds, canals, ditches, irrigated land, similar shallowly flooded areas. Seacoasts, reefs and islands are used on migration. For nesting, it tends to prefer dense trees and shrubs near its feeding areas.
BEHAVIOR
Often overlooked because it blends into dense vegetation. Roosts in groups, using sheltered woods or reed beds. The alarm and flight call given when disturbed or when flying to and from roosts is highly recognizable, giving the bird its name.
FEEDING ECOLOGY AND DIET
Typically feeds by searching for prey in a standing, crouched posture, either in the open or among the reeds. Usually feeds alone, defending its territory, although it also feeds in small groups or large flocks in winter and on migration. Feeding success is higher for solitary birds than those feeding in flocks. Feeds during the day, especially at twilight. Diet is relatively small prey, particularly fish, frogs, and tadpoles, as well as insects and insect larvae.
REPRODUCTIVE BIOLOGY
Herons in Europe and North Africa nest from late spring to summer. In tropical Africa, it breeds primarily in the rainy season. Nests in dense bushes or small trees, near or overhanging water, and less frequently in reed beds and papyrus swamps, using either the reed or small trees. Typically nests colonially with other species, although sometimes solitarily. Nests are small, bulky, and compact, 7–11 in (17–27 cm) in diameter made of reeds, grass, and twigs. Eggs are greenish blue. The clutch is four to six eggs in Europe, three to four in Madagascar and southern Africa. Clutch sizes have decreased in southern Europe over several decades. Incubation is 22–24 days in Europe, 18 days in Madagascar. Young begin to clamber from the nest into branches at 14 days. They are fledged at 45 days (35 days in Madagascar). Young form groups at the colony site.
CONSERVATION STATUS
Not threatened, but its populations are variable. Historic declines appear to be due to a combination of hunting, habitat change, and perhaps climate. In some areas, the bird has increased its range in recent decades, likely due to its concentrated use of rice fields.
SIGNIFICANCE TO HUMANS
Often occurs close to humans, living in rice fields and marshes adjacent to towns and villages. It is not often noticed, but its call is distinctive.
