Falconiformes
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 Black-shouldered
Kite
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Families
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Accipitridae Pandionidae Falconidae Sagittariidae |
The order Falconiformes is a group of about 290 species of birds that include the diurnal birds of prey. Raptor classification is fraught with difficulty and the order is treated in several different ways.
Classification problems
Traditionally, all the raptors are grouped into 4 families in this single order. However, in Europe, it has become common to split the order into two: the falcons and caracaras remain in the order Falconiformes (about 60 species in 4 groups), while the remaining 220-odd species (including the Accipitridae—eagles, hawks, and many others) are placed in the separate order Accipitriformes.
The American Ornithologist's Union leaves Falconidae and Accipitridae in Falconiformes, but places the New World vultures (family Cathartidae) with the storks in Ciconiiformes following the influential Sibley-Ahlquist taxonomy, in which all the raptors are placed into Ciconiiformes, but the Cathartids are considered to be outside the lineage that includes other raptors.
The idea that Falconiformes should be divided into many orders is because of the suggestion that the order may not share a single lineage that is exclusive of other birds. The most controversial suggestion - but also the most well-supported one - is that Cathartidae are not Falconiformes but are related to the storks, in the separate order Ciconiiformes. However morphological evidence supports the common ancestry of the Falconiformes, and the Strigiformes may be Falconiformes as well.
Characteristics
Falconiformes are known from the Middle Eocene and typically have a sharply hooked beak with a cere (soft mass) on the proximodorsal surface, housing the nostrils. Their wings are long and fairly broad, suitable for soaring flight, with the outer 4-6 primaries emarginated.
Falconiformes have strong legs and feet with raptorial claws and an opposable hind claw. Almost all Falconiformes are carnivorous, hunting by sight during the day or at twilight. They are exceptionally long-lived, and most have low reproductive rates.
The young have a long, very fast-growing fledgling stage, followed by 3-8 weeks of nest care after first flight and 1-3 years as sexually immature adults. The sexes have conspicuously different sizes, and monogamy is the general rule.
DNA studies mean that it is likely to be some time until a consensus is restored on this group of birds.
See
- Sibley-Ahlquist taxonomy.