For a long time, the majority view was to include them with the falcons in the
Falconiformes, but many authorities now recognize a separate from Accipitriformes.[3][4][5][6] A
DNA study published in 2008 indicated that falcons are not closely related to the Accipitriformes, being instead more closely related to
parrots and
passerines.[7] Since then, the
split and the placement of the falcons next to the parrots in taxonomic order has been adopted by the
American Ornithological Society's South American Classification Committee (SACC),[8][9][10] its North American Classification Committee (NACC),[11][12] and the International Ornithological Congress (IOC).[13][14] The British Ornithologists' Union already recognized the Accipitriformes,[15] and has adopted the move of Falconiformes.[16] The DNA-based proposal and the NACC and IOC classifications include the
New World vultures in the Accipitriformes,[7][11] while the SACC classifies the New World vultures as a separate order, the
Cathartiformes.
Characteristics
The Accipitriformes are known from the Middle
Eocene[citation needed] and typically have a sharply hooked
beak with a soft
cere housing the
nostrils. Their
wings are long and fairly broad, suitable for soaring flight, with the outer four to six primary feathers emarginated.
They have strong legs and feet with raptorial
claws and opposable hind claws. Almost all Accipitriformes are
carnivorous, hunting by sight during the day or at twilight. They are exceptionally long-lived, and most have low
reproductive rates.[citation needed]
The young have a long, very fast-growing fledgling stage, followed by 3–8 weeks of nest care after first flight, and 1 to 3 years as
sexually immature adults. The sexes have conspicuously different sizes and sometimes a female is more than twice as heavy as her mate. This
sexual dimorphism is sometimes most extreme in specialized bird-eaters, such as the Accipiter hawks.
Monogamy is the general rule, although an alternative mate is often selected if one dies.
Taxonomy
Accipitriformes, currently with 262 species and 75 genera in 4 extant families and possibly 1 extinct family, is the largest diurnal raptor order. DNA sequence analyses suggest that divergences within Accipitriformes began around the Eocene/Oligocene boundary about 34 mya, with the split of the group including genera Elanus and Gampsonyx from the other Accipitriformes genera.[17]
The order includes the following families:
Order Accipitriformes
Phylogeny based on Nagy, J. & Tökölyi, J. (2014).[18]
Footnotes
^Mayr G, Smith T. A diverse bird assemblage from the Ypresian of Belgium furthers knowledge of early Eocene avifaunas of the North Sea Basin. N Jb Geol Paläontol, Abh. 2019;291:253–281. doi: 10.1127/njgpa/2019/0801.
^Mindell, David; Fuchs, Jerome; Johnson, Jeff (2018). "Phylogeny, Taxonomy, and Geographic Diversity of Diurnal Raptors: Falconiformes, Accipitriformes, and Cathartiformes.". In Sarasola, José Hernán; Grande, Juan Manuel; Negro, Juan José (eds.). Birds of Prey Biology and conservation in the XXI century. Springer. pp. 3–32.
doi:
10.1007/978-3-319-73745-4.
ISBN978-3-319-73744-7.
S2CID49622660.
Hackett, Shannon J.; Kimball, Rebecca T.; Reddy, Sushma; Bowie, Rauri C. K.; Braun, Edward L.; Braun, Michael J.; Chojnowski, Jena L.; Cox, W. Andrew; Han, Kin-Lan; Harshman, John; Huddleston, Christopher J.; Marks, Ben D.; Miglia, Kathleen J.; Moore, William S.; Sheldon, Frederick H.; Steadman, David W.; Witt, Christopher C.; Yuri, Tamaki (2008). "A phylogenomic study of birds reveals their evolutionary history". Science. 320 (5884): 1763–68.
Bibcode:
2008Sci...320.1763H.
doi:
10.1126/science.1157704.
PMID18583609.
S2CID6472805.
Gill, Frank; Donsker, D. (2014).
"Updates". IOC World Bird List.
Archived from the original on 2014-09-24. Retrieved 2014-09-30. Falconiformes was resequenced in version 4.1 (Jan 7, 2014)