![]() ![]() Beaks also vary with prey: short and robust in most species, particularly deep in species that take large prey longer and less powerful in carrion eaters. Hence, toes of bird-catching species are long and slender, mammal eaters have thicker toes, and snake eaters the shortest and thickest. Other structures also vary with lifestyle, form reflecting function. The exception is the caracaras, which have heavy but flatter talons for their more terrestrial, vulture-like lifestyle. ![]() Most falconids have strong needle-sharp talons. (accipitrids squeeze with their feet), and eggs that have reddish translucence when held up to the light (accipitrid eggs are bluish or greenish). The difference between the sexes is greatest in bird-eaters (female around 150% of male weight), intermediate in mammal-eaters, and least in insect-eaters and scavengers (females marginally heavier).ĭifferences between the families include several anatomical features, such as the structure of the syrinx, the fact that falconids kill with the beak or by the blow when they strike ![]() Both families capture animals with their feet and, unlike most bird species, females are larger than males. Both have a fleshy cere atop a strong hooked beak, and a strong hallux (hind toe) that opposes three forward toes. Physical characteristicsįalconids are readily recognizable as birds of prey and are likely to be confused only with the other family of diurnal raptors, the Accipitridae. Nevertheless, each major region has its group of similar, presumably closely related forms (gray falcon, black falcon, brown falcon and New Zealand falcon in Australasia) and there are a few groups of more widespread sister species (the desert falcons, kestrels, peregrines, and hobbies). Within the family, division into the two subfamilies is well supported but there is much argument over relationships within each. The falcons, genus Falco, the largest group of falconids, are clearly closely related and are thought to have undergone rapid radiation and expansion early in the Pleistocene (about 1.85 million years ago), when the grasslands opened up. In the Americas, falconids have been identified from 23 million years ago, including a caracara-like form. ![]() Better-substantiated fossil members of the family have been reported from 36-million-year-old deposits in France. The earliest fossil attributed to the family was found in England and dated to 55 million years ago. Contemporary caracaras and forest falcons (Polyborinae) are South and Central American, and there is no indication the subfamily was ever otherwise, so it seems reasonable to suggest they arose in the neotropics. Africa now has the greatest diversity of falcons, but that does not necessarily reflect their past distribution or give clues about where they might have arisen. There is no good fossil evidence to suggest where the family might have originated geographically. Nevertheless, in most modern classifications they are still placed with the accipitrids in the order Falconiformes. One classification, based on DNA hybridization, groups them within the Ciconiiformes (herons, storks, and ibises). Yet molecular evidence suggests that in both cases the resemblance is convergent that they have evolved to look and behave in a similar fashion because of their similar lifestyles. Their similarity to the accipitrids (family Accipitridae, hawks and eagles) is obvious, and it has been suggested that they have morphological and anatomical links with the owls. The relationship of falconids to other birds has long been unclear. Worldwide, except the Antarctic Evolution and systematics Vulnerable: 4 species Near Threatened: 6 species one subspecies Extinct Most habitats, from treeless desert and tundra to dry forest and rainforest, featureless plains to rugged gorges and escarpments Small to medium-sized largely diurnal raptors with strong feet, usually pointed wings, and sharply curved beaks from scavengers to among the swiftest and, for their size, most powerful of avian predatorsĥ.5–25.6 in (14–65 cm) 0.06–4.6 lb (28–2,100 g) ![]()
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