Bird of prey

For other uses, see Birds of Prey (disambiguation), Bird of Prey (disambiguation), and Raptor (disambiguation).

Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predators have keen eyesight for detecting prey from a distance or during flight, strong feet with sharp talons for grasping or killing prey, and powerful, curved beaks for tearing off flesh.^[1][2][3] Although predatory birds primarily hunt live prey, many species (such as fish eagles, vultures and condors) also scavenge and eat carrion.^[1]

Birds of prey
Montage of extant raptors. From top left to right: eurasian eagle-owl, king vulture, peregrine falcon, golden eagle and bearded vulture
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Class:	Aves
Clade:	Passerea
Clade:	Telluraves
Groups included
Strigiformes Cathartiformes Accipitriformes Falconiformes Cariamiformes
Cladistically included but traditionally excluded taxa
Coraciimorphae Psittacopasserae

Although the term "bird of prey" could theoretically be taken to include all birds that actively hunt and eat other animals,^[3] ornithologists typically use the narrower definition followed in this page,^[4] excluding both piscivorous predators such as storks, herons, gulls, skuas, penguins and kingfishers, as well as primarily insectivorous birds such as passerine birds (e.g. shrikes) and birds like nightjars and frogmouths. Some extinct predatory birds had talons similar to those of modern birds of prey, including mousebird relatives (Sandcoleidae),^[5] Messelasturidae and some Enantiornithes,^[6] indicating possible convergent evolution.

Common names

The term raptor is derived from the Latin word rapio, meaning "to seize or take by force".^[7] The common names for various birds of prey are based on structure, but many of the traditional names do not reflect the evolutionary relationships between the groups.

 

Variations in shape and size

• Eagles tend to be large, powerful birds with long, broad wings and massive feet. Booted eagles have legs and feet feathered to the toes and build very large stick nests.
• Falcons and kestrels are medium-size birds of prey with long pointed wings, and many are particularly swift flyers. They belong to the family Falconidae, only distantly related to the Accipitriformes above. Caracaras are a distinct subgroup of the Falconidae unique to the New World, and most common in the Neotropics – their broad wings, naked faces and appetites of a generalist suggest some level of convergence with either Buteo or the vulturine birds, or both.
• True hawks are medium-sized birds of prey that usually belong to the genus Accipiter (see below). They are mainly woodland birds that hunt by sudden dashes from a concealed perch. They usually have long tails for tight steering.
• Buzzards are medium-large raptors with robust bodies and broad wings, or, alternatively, any bird of the genus Buteo (also commonly known as "hawks" in North America, while "buzzard" is colloquially used for vultures).
• Harriers are large, slender hawk-like birds with long tails and long thin legs. Most use a combination of keen eyesight and hearing to hunt small vertebrates, gliding on their long broad wings and circling low over grasslands and marshes.
• Kites have long wings and relatively weak legs. They spend much of their time soaring. They will take live vertebrate prey, but mostly feed on insects or even carrion.
• The osprey, a single species found worldwide that specializes in catching fish and builds large stick nests.
• Owls are variable-sized, typically night-specialized hunting birds. They fly almost silently due to their special feather structure that reduces turbulence. They have particularly acute hearing and nocturnal eyesight.
• The secretarybird is a single species with a large body and long, stilted legs endemic to the open grasslands of Sub-Saharan Africa.
• Vultures are scavengers and carrion-eating raptors of two distinct biological families: the Old World vultures (Accipitridae), which occurs only in the Eastern Hemisphere; and the New World vultures (Cathartidae), which occurs only in the Western Hemisphere. Members of both groups have heads either partly or fully devoid of feathers.
• Seriemas,^[8] large South American birds with long, stilted legs that occupy a similar ecological niche to secretarybirds. They are also the closest relatives to the extinct "terror birds".

Many of these English language group names originally referred to particular species encountered in Britain. As English-speaking people travelled further, the familiar names were applied to new birds with similar characteristics. Names that have generalised this way include: kite (Milvus milvus), sparrow-hawk or sparhawk (Accipiter nisus), goshawk (Accipiter gentilis), kestrel (Falco tinninculus), hobby (Falco subbuteo), harrier (simplified from "hen-harrier", Circus cyaneus), buzzard (Buteo buteo).

Some names have not generalised, and refer to single species (or groups of closely related (sub)species), such as the merlin (Falco columbarius).

Systematics

Historical classifications

The taxonomy of Carl Linnaeus grouped birds (class Aves) into orders, genera, and species, with no formal ranks between genus and order. He placed all birds of prey into a single order, Accipitres, subdividing this into four genera: Vultur (vultures), Falco (eagles, hawks, falcons, etc.), Strix (owls), and Lanius (shrikes). This approach was followed by subsequent authors such as Gmelin, Latham and Turton.

Louis Pierre Veillot used additional ranks: order, tribe, family, genus, species. Birds of prey (order Accipitres) were divided into diurnal and nocturnal tribes; the owls remained monogeneric (family Ægolii, genus Strix), whilst the diurnal raptors were divided into three families: Vulturini, Gypaëti, and Accipitrini.^[9] Thus Veillot's families were similar to the Linnaean genera, with the difference that shrikes were no longer included amongst the birds of prey. In addition to the original Vultur and Falco (now reduced in scope), Veillot adopted four genera from Savigny: Phene, Haliæetus, Pandion, and Elanus. He also introduced five new genera of vultures (Gypagus, Catharista, Daptrius, Ibycter, Polyborus)^{[note 1]} and eleven new genera of accipitrines (Aquila, Circaëtus, Circus, Buteo, Milvus, Ictinia, Physeta, Harpia, Spizaëtus, Asturina, Sparvius).

Falconimorphae is a deprecated superorder within Raptores, formerly composed of the orders Falconiformes and Strigiformes. The clade was invalidated after 2012. Falconiformes is now placed in Eufalconimorphae, while Strigiformes is placed in Afroaves.^[10]

Modern systematics

 

Bald eagle

The order Accipitriformes is believed to have originated 44 million years ago when it split from the common ancestor of the secretarybird (Sagittarius serpentarius) and the accipitrid species.^[11] The phylogeny of Accipitriformes is complex and difficult to unravel. Widespread paraphylies were observed in many phylogenetic studies.^{[12][13][14][15][16]} More recent and detailed studies show similar results.^[17] However, according to the findings of a 2014 study, the sister relationship between larger clades of Accipitriformes was well supported (e.g. relationship of Harpagus kites to buzzards and sea eagles and these latter two with Accipiter hawks are sister taxa of the clade containing Aquilinae and Harpiinae).^[11]

The diurnal birds of prey are formally classified into six families of three different orders (Accipitriformes, Falconiformes and Cariamiformes).

• Accipitridae: hawks, eagles, buzzards, harriers, kites, and Old World vultures
• Pandionidae: the osprey
• Sagittariidae: the secretarybird
• Falconidae: falcons, caracaras, and forest falcons
• Cathartidae: New World vultures, including condors
• Cariamidae: seriemas^[8]

These families (with the exception of Cariamidae) were traditionally grouped together in a single order Falconiformes but are now split into two orders, the Falconiformes and Accipitriformes. The Cathartidae are sometimes placed separately in an enlarged stork family, Ciconiiformes, and may be raised to an order of their own, Cathartiiformes.

The secretary bird and/or osprey are sometimes listed as subfamilies of Acciptridae: Sagittariinae and Pandioninae, respectively.

Australia's letter-winged kite is a member of the family Accipitridae, although it is a nocturnal bird.

The nocturnal birds of prey—the owls—are classified separately as members of two extant families of the order Strigiformes:

• Strigidae: "typical owls"
• Tytonidae: barn and bay owls

Phylogeny

Below is a simplified phylogeny of Telluraves which is the clade where the birds of prey belong to along with passerines and several near-passerine lineages.^[18][10][19] The orders in bold text are birds of prey orders; this is to show the polyphyly of the group as well as their relationships to other birds.

Telluraves	Afroaves Accipitrimorphae Accipitriformes (hawks and relatives)   Cathartiformes (New World vultures)  Strigiformes (owls)  Coraciimorphae (woodpeckers, rollers, hornbills, etc.)  Australaves Cariamiformes (seriemas)  Eufalconimorphae Falconiformes (falcons)  Psittacopasserae (parrots and songbirds)

Migration

Migratory behaviour evolved multiple times within accipitrid raptors.

 

An obliged point of transit of the migration of the birds of prey is the bottleneck-shaped Strait of Messina, Sicily, here seen from Dinnammare mount, Peloritani.

The earliest event occurred nearly 14 to 12 million years ago. This result seems to be one of the oldest dates published so far in the case of birds of prey.^[11] For example, a previous reconstruction of migratory behaviour in one Buteo clade^[16] with a result of the origin of migration around 5 million years ago was also supported by that study.

Migratory species of raptors may have had a southern origin because it seems that all of the major lineages within Accipitridae had an origin in one of the biogeographic realms of the Southern Hemisphere. The appearance of migratory behaviour occurred in the tropics parallel with the range expansion of migratory species to temperate habitats.^[11] Similar results of southern origin in other taxonomic groups can be found in the literature.^[20][21][22]

Distribution and biogeographic history highly determine the origin of migration in birds of prey. Based on some comparative analyses, diet breadth also has an effect on the evolution of migratory behaviour in this group,^[11] but its relevance needs further investigation. The evolution of migration in animals seems to be a complex and difficult topic with many unanswered questions.

A recent study discovered new connections between migration and the ecology, life history of raptors. A brief overview from abstract of the published paper shows that "clutch size and hunting strategies have been proved to be the most important variables in shaping distribution areas, and also the geographic dissimilarities may mask important relationships between life history traits and migratory behaviours. The West Palearctic-Afrotropical and the North-South American migratory systems are fundamentally different from the East Palearctic-Indomalayan system, owing to the presence versus absence of ecological barriers."^[23] Maximum entropy modelling can help in answering the question: why species winters at one location while the others are elsewhere. Temperature and precipitation related factors differ in the limitation of species distributions. "This suggests that the migratory behaviours differ among the three main migratory routes for these species"^[23] which may have important conservational consequences in the protection of migratory raptors.

Sexual dimorphism

 

Male (left) and female (right) red-footed falcons

Birds of prey (raptors) are known to display patterns of sexual dimorphism. It is commonly believed that the dimorphisms found in raptors occur due to sexual selection or environmental factors. In general, hypotheses in favor of ecological factors being the cause for sexual dimorphism in raptors are rejected. This is because the ecological model is less parsimonious, meaning that its explanation is more complex than that of the sexual selection model. Additionally, ecological models are much harder to test because a great deal of data is required.^[24]

Dimorphisms can also be the product of intrasexual selection between males and females. It appears that both sexes of the species play a role in the sexual dimorphism within raptors; females tend to compete with other females to find good places to nest and attract males, and males competing with other males for adequate hunting ground so they appear as the most healthy mate.^[25] It has also been proposed that sexual dimorphism is merely the product of disruptive selection, and is merely a stepping stone in the process of speciation, especially if the traits that define gender are independent across a species. Sexual dimorphism can be viewed as something that can accelerate the rate of speciation.^[26]

In non-predatory birds, males are typically larger than females. However, in birds of prey, the opposite is the case. For instance, the kestrel is a type of falcon in which males are the primary providers, and the females are responsible for nurturing the young. In this species, the smaller the kestrels are, the less food is needed and thus, they can survive in environments that are harsher. This is particularly true in the male kestrels. It has become more energetically favorable for male kestrels to remain smaller than their female counterparts because smaller males have an agility advantage when it comes to defending the nest and hunting. Larger females are favored because they can incubate larger numbers of offspring, while also being able to brood a larger clutch size.^[27]

Olfaction

It is a long-standing belief that birds lack any sense of smell, but it has become clear that many birds do have functional olfactory systems. Despite this, most raptors are still considered to primarily rely on vision, with raptor vision being extensively studied. A 2020 review of the existing literature combining anatomical, genetic, and behavioural studies showed that, in general, raptors have functional olfactory systems that they are likely to use in a range of different contexts.^[28]

Persecution

Birds of prey have been historically persecuted both directly and indirectly. In the Danish Faroe Islands, there were rewards Naebbetold (by royal decree from 1741) given in return for the bills of birds of prey shown by hunters. In Britain, kites and buzzards were seen as destroyers of game and killed, for instance in 1684-5 alone as many as 100 kites were killed. Rewards for their killing were also in force in the Netherlands from 1756. From 1705 to 1800, it has been estimated that 624087 birds of prey were killed in a part of Germany that included Hannover, Luneburg, Lauenburg and Bremen with 14125 claws deposited just in 1796–97.^[29] Many species also develop lead poisoning after accidental consumption of lead shot when feeding on animals that had been shot by hunters.^[30] Lead pellets from direct shooting that the birds have escaped from also cause reduced fitness and premature deaths.^[31]

Attacks on humans

Some evidence supports the contention that the African crowned eagle occasionally views human children as prey, with a witness account of one attack (in which the victim, a seven-year-old boy, survived and the eagle was killed),^[32] and the discovery of part of a human child skull in a nest. This would make it the only living bird known to prey on humans, although other birds such as ostriches and cassowaries have killed humans in self-defense and a lammergeier might have killed Aeschylus by accident.^[33] Many stories of Brazilian indigenous peoples speak about children mauled by Uiruuetê, the Harpy Eagle in Tupi language.^{[citation needed]} Various large raptors like golden eagles are reported attacking human beings,^[34] but its unclear if they intend to eat them or if they have ever been successful in killing one.

Some fossil evidence indicates large birds of prey occasionally preyed on prehistoric hominids. The Taung Child, an early human found in Africa, is believed to have been killed by an eagle-like bird similar to the crowned eagle. The Haast's eagle may have preyed on early humans in New Zealand, and this conclusion would be consistent with Maori folklore. Leptoptilos robustus^[35] might have preyed on both Homo floresiensis and anatomically modern humans, and the Malagasy crowned eagle, teratorns, Woodward's eagle and Caracara major^[36] are similar in size to the Haast's eagle, implying that they similarly could pose a threat to a human being.

Vision

Birds of prey have incredible vision and rely heavily on it for a number of tasks.^[37] They utilize their high visual acuity to obtain food, navigate their surroundings, distinguish and flee from predators, mating, nest construction, and much more. They accomplish these tasks with a large eye in relation to their skull, which allows for a larger image to be projected onto the retina.^[37] The visual acuity of some large raptors such as eagles and Old World vultures are the highest known among vertebrates; the wedge-tailed eagle has twice the visual acuity of a typical human and six times that of the common ostrich, the vertebrate with the largest eyes.^[38]

There are two regions in the retina, called the deep and shallow fovea, that are specialized for acute vision. ^[39] These regions contain the highest density of photoreceptors, and provide the highest points of visual acuity. The deep fovea points forward at an approximate 45° angle, while the shallow fovea points approximately 15° to the right or left of the head axis. ^[39] Several raptor species repeatedly cock their heads into three distinct positions while observing an object. First, is straight ahead with their head pointed towards the object. Second and third are sideways to the right or left of the object, with their head axis positioned approximately 40° adjacent to the object. This movement is believed to be associated with lining up the incoming image to fall on the deep fovea. Raptors will choose which head position to use depending on the distance to the object. At distances as close as 8m, they used primarily binocular vision. At distances greater than 21m, they spent more time using monocular vision. At distances greater than 40m, they spent 80% or more time using their monocular vision. This suggests that raptors tilt their head to rely on the highly acute deep fovea. ^[39]

Like all birds, raptors possess tetrachromacy, however, due to their emphasis on visual acuity, many diurnal birds of prey have little ability to see ultraviolet light as this produces chromatic aberration which decreases the clarity of vision.^[40]

See also

•  Birds portal

• Origin of birds

Explanatory notes

1. Veillot included the caracaras (Daptrius, Ibycter, and Polyborus) in Vulturini, though it is now known that they are related to falcons.

References

1. Perrins, Christopher, M; Middleton, Alex, L. A., eds. (1984). The Encyclopaedia of Birds. Guild Publishing. p. 102.{{cite book}}: CS1 maint: multiple names: editors list (link)
2. Fowler, Denver W.; Freedman, Elizabeth A.; Scannella, John B.; Pizzari, Tom (25 November 2009). "Predatory Functional Morphology in Raptors: Interdigital Variation in Talon Size Is Related to Prey Restraint and Immobilisation Technique". PLOS ONE. 4 (11): e7999. Bibcode:2009PLoSO...4.7999F. doi:10.1371/journal.pone.0007999. PMC 2776979. PMID 19946365.
3. Burton, Philip (1989). Birds of Prey. illustrated by Boyer, Trevor; Ellis, Malcolm; Thelwell, David. Gallery Books. p. 8. ISBN 978-0-8317-6381-7.
4. "World Book". www.worldbookonline.com. Retrieved 2023-10-05. https://www.worldbookonline.com/advanced/article?id=ar752148
5. Mayr, Gerald (19 April 2018). "New data on the anatomy and palaeobiology of sandcoleid mousebirds (Aves, Coliiformes) from the early Eocene of Messel". Palaeobiodiversity and Palaeoenvironments. 98 (4): 639–651. doi:10.1007/s12549-018-0328-1. S2CID 134450324.
6. Xing, Lida; McKellar, Ryan C.; O'Connor, Jingmai K.; Niu, Kecheng; Mai, Huijuan (29 October 2019). "A mid-Cretaceous enantiornithine foot and tail feather preserved in Burmese amber". Scientific Reports. 9 (1): 15513. Bibcode:2019NatSR...915513X. doi:10.1038/s41598-019-51929-9. PMC 6820775. PMID 31664115.
7. Brown, Leslie (1997). Birds of Prey. Chancellor Press. ISBN 978-1-85152-732-8.
8. McClure, Christopher J. W.; Schulwitz, Sarah E.; Anderson, David L.; Robinson, Bryce W.; Mojica, Elizabeth K.; Therrien, Jean-Francois; Oleyar, M. David; Johnson, Jeff (2019). "Commentary: Defining Raptors and Birds of Prey". Journal of Raptor Research. BioOne COMPLETE. 53 (4): 419. doi:10.3356/0892-1016-53.4.419. S2CID 207933673.
9. Veillot, Louis Pierre (1816). Saunders, Howard (ed.). Analyse d'une nouvelle ornithologie élémentaire (in French) (London 1883 ed.). Willughby Society.^{[page needed]}
10. Ericson, Per G. P. (2012). "Evolution of terrestrial birds in three continents: biogeography and parallel radiations" (PDF). Journal of Biogeography. 39 (5): 813–824. doi:10.1111/j.1365-2699.2011.02650.x.
11. Nagy, Jenő; Tökölyi, Jácint (1 June 2014). "Phylogeny, Historical Biogeography and the Evolution of Migration in Accipitrid Birds of Prey (Aves: Accipitriformes)". Ornis Hungarica. 22 (1): 15–35. doi:10.2478/orhu-2014-0008.
12. Wink, Michael; Sauer-Gürth, Hedi (2004). "Phylogenetic relationships in diurnal raptors based on nucleotide sequences of mitochondrial and nuclear marker genes" (PDF). In Chancellor, Robin D.; Meyburg, Bernd-U. (eds.). Raptors Worldwide: Proceedings of the VI World Conference on Birds of Prey and Owls, Budapest, Hungary, 18–23 May 2003. World Working Group on Birds of Prey and Owls, MME/BirdLife Hungary. pp. 483–498. ISBN 978-963-86418-1-6.
13. Helbig, Andreas J.; Kocum, Annett; Seibold, Ingrid; Braun, Michael J. (April 2005). "A multi-gene phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level". Molecular Phylogenetics and Evolution. 35 (1): 147–164. doi:10.1016/j.ympev.2004.10.003. PMID 15737588.
14. Lerner, Heather R.L.; Mindell, David P. (November 2005). "Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA". Molecular Phylogenetics and Evolution. 37 (2): 327–346. doi:10.1016/j.ympev.2005.04.010. PMID 15925523.
15. Griffiths, Carole S.; Barrowclough, George F.; Groth, Jeff G.; Mertz, Lisa A. (September 2007). "Phylogeny, diversity, and classification of the Accipitridae based on DNA sequences of the RAG-1 exon". Journal of Avian Biology. 38 (5): 587–602. doi:10.1111/j.2007.0908-8857.03971.x.
16. do Amaral, Fábio Raposo; Sheldon, Frederick H.; Gamauf, Anita; Haring, Elisabeth; Riesing, Martin; Silveira, Luís F.; Wajntal, Anita (December 2009). "Patterns and processes of diversification in a widespread and ecologically diverse avian group, the buteonine hawks (Aves, Accipitridae)". Molecular Phylogenetics and Evolution. 53 (3): 703–715. doi:10.1016/j.ympev.2009.07.020. PMID 19635577.
17. Breman, Floris C.; Jordaens, Kurt; Sonet, Gontran; Nagy, Zoltán T.; Van Houdt, Jeroen; Louette, Michel (23 September 2012). "DNA barcoding and evolutionary relationships in Accipiter Brisson, 1760 (Aves, Falconiformes: Accipitridae) with a focus on African and Eurasian representatives". Journal of Ornithology. 154 (1): 265–287. doi:10.1007/s10336-012-0892-5. S2CID 17933934.
18. Yuri, Tamaki; Kimball, Rebecca; Harshman, John; Bowie, Rauri; Braun, Michael; Chojnowski, Jena; Han, Kin-Lan; Hackett, Shannon; Huddleston, Christopher; Moore, William; Reddy, Sushma; Sheldon, Frederick; Steadman, David; Witt, Christopher; Braun, Edward (13 March 2013). "Parsimony and Model-Based Analyses of Indels in Avian Nuclear Genes Reveal Congruent and Incongruent Phylogenetic Signals". Biology. 2 (1): 419–444. doi:10.3390/biology2010419. PMC 4009869. PMID 24832669.
19. Jarvis, Erich D.; Mirarab, Siavash; Aberer, Andre J.; Li, Bo; Houde, Peter; Li, Cai; Ho, Simon Y. W.; Faircloth, Brant C.; Nabholz, Benoit; Howard, Jason T.; Suh, Alexander; Weber, Claudia C.; da Fonseca, Rute R.; Li, Jianwen; Zhang, Fang; Li, Hui; Zhou, Long; Narula, Nitish; Liu, Liang; Ganapathy, Ganesh; Boussau, Bastien; Bayzid, Md. Shamsuzzoha; Zavidovych, Volodymyr; Subramanian, Sankar; Gabaldón, Toni; Capella-Gutiérrez, Salvador; Huerta-Cepas, Jaime; Rekepalli, Bhanu; Munch, Kasper; et al. (12 December 2014). "Whole-genome analyses resolve early branches in the tree of life of modern birds". Science. 346 (6215): 1320–1331. Bibcode:2014Sci...346.1320J. doi:10.1126/science.1253451. PMC 4405904. PMID 25504713.
20. Joseph, Leo; Lessa, Enrique P.; Christidis, Leslie (March 1999). "Phylogeny and biogeography in the evolution of migration: shorebirds of the Charadrius complex". Journal of Biogeography. 26 (2): 329–342. doi:10.1046/j.1365-2699.1999.00269.x. S2CID 86547121.
21. Outlaw, Diana C.; Voelker, Gary; Mila, Borja; Girman, Derek J. (2003). "Evolution of Long-Distance Migration in and Historical Biogeography of Catharus Thrushes: A Molecular Phylogenetic Approach". The Auk. 120 (2): 299. doi:10.1642/0004-8038(2003)120[0299:EOLMIA]2.0.CO;2. JSTOR 4090182. S2CID 53002864.
22. Milá, Borja; Smith, Thomas B.; Wayne, Robert K. (November 2006). "Postglacial population expansion drives the evolution of long–distance migration in a songbird". Evolution. 60 (11): 2403–2409. doi:10.1111/j.0014-3820.2006.tb01875.x. PMID 17236431.
23. Nagy, Jenő; Végvári, Zsolt; Varga, Zoltán (1 May 2017). "Life history traits, bioclimate, and migratory systems of accipitrid birds of prey (Aves: Accipitriformes)". Biological Journal of the Linnean Society. 121 (1): 63–71. doi:10.1093/biolinnean/blw021.
24. Mueller, Helmut C. (1986). "The Evolution of Reversed Sexual Dimorphism in Owls: An Empirical Analysis of Possible Selective Factors". The Wilson Bulletin. 98 (3): 387–406. JSTOR 4162266.
25. Massemin, S.; Korpimäki, Erkki; Wiehn, Jürgen (21 July 2000). "Reversed sexual size dimorphism in raptors: evaluation of the hypotheses in kestrels breeding in a temporally changing environment". Oecologia. 124 (1): 26–32. Bibcode:2000Oecol.124...26M. doi:10.1007/s004420050021. PMID 28308409. S2CID 8498728.
26. Bolnick, Daniel I.; Doebeli, Michael (November 2003). "Sexual dimorphism and adaptive speciation: two sides of the same ecological coin". Evolution. 57 (11): 2433–2449. doi:10.1111/j.0014-3820.2003.tb01489.x. PMID 14686521.
27. Sonerud, Geir A.; Steen, Ronny; Løw, Line M.; Røed, Line T.; Skar, Kristin; Selås, Vidar; Slagsvold, Tore (17 October 2012). "Size-biased allocation of prey from male to offspring via female: family conflicts, prey selection, and evolution of sexual size dimorphism in raptors". Oecologia. 172 (1): 93–107. Bibcode:2013Oecol.172...93S. doi:10.1007/s00442-012-2491-9. PMID 23073637. S2CID 17489247.
28. Potier, Simon (2020). "Olfaction in raptors". Zoological Journal of the Linnean Society. 189 (3): 713–721. doi:10.1093/zoolinnean/zlz121.
29. Bijleveld, Maarten (1974). Birds of Prey in Europe. Macmillan International Higher Education. pp. 1–5.
30. Benson, W. W.; Pharaoh, Barry; Miller, Pamela (1974). "Lead poisoning in a bird of prey". Bulletin of Environmental Contamination and Toxicology. 11 (2): 105–108. doi:10.1007/BF01684587. ISSN 0007-4861. PMID 4433788. S2CID 42626967.
31. Krone, Oliver (2018). "Lead Poisoning in Birds of Prey". In Sarasola, José Hernán; Grande, Juan Manuel; Negro, Juan José (eds.). Birds of Prey. Cham: Springer International Publishing. pp. 251–272. doi:10.1007/978-3-319-73745-4_11. ISBN 978-3-319-73744-7. Retrieved 2021-12-28.
32. Steyn, P. 1982. Birds of prey of southern Africa: their identification and life histories. David Phillip, Cape Town, South Africa.
33. el Hoyo, J.; Elliott, A.; Sargatal, J., eds. (1994). Handbook of the Birds of the World. 2. Barcelona: Lynx Edicions. p. 107. ISBN 84-87334-15-6.
34. Dickinson, Rachel (2009). Falconer on the Edge. Houghton Mifflin-Harcourt. ISBN 978-0-618-80623-2.
35. Meijer, Hanneke J.M.; Due, Rokus AWE (2010). "A new species of giant marabou stork (Aves: Ciconiiformes) from the Pleistocene of Liang Bua, Flores (Indonesia)". Zoological Journal of the Linnean Society. 160 (4): 707–724. doi:10.1111/j.1096-3642.2010.00616.x.
36. Jones, Washington; Rinderknecht, Andrés; Migotto, Rafael; Blanco, R. Ernesto (2013). "Body Mass Estimations and Paleobiological Inferences on a New Species of Large Caracara (Aves, Falconidae) from the Late Pleistocene of Uruguay". Journal of Paleontology. 87 (1): 151–158. Bibcode:2013JPal...87..151J. doi:10.1666/12-026R.1. JSTOR 23353814. S2CID 83648963.
37. Jones, Michael P.; Pierce, Kenneth E.; Ward, Daniel (April 2007). "Avian Vision: A Review of Form and Function with Special Consideration to Birds of Prey". Journal of Exotic Pet Medicine. 16 (2): 69–87. doi:10.1053/j.jepm.2007.03.012. Retrieved 7 June 2023.
38. Mitkus, Mindaugas; Potier, Simon; Martin, Graham R.; Duriez, Olivier; Kelber, Almut (2018-04-26), "Raptor Vision", Oxford Research Encyclopedia of Neuroscience, doi:10.1093/acrefore/9780190264086.013.232, ISBN 978-0-19-026408-6, retrieved 2023-07-30
39. Tucker, Vance A. (15 December 2000). "The Deep Fovea, Sideways Vision and Spiral Flight Paths in Raptors". Journal of Experimental Biology. 203 (24): 3745–3754. doi:10.1242/jeb.203.24.3745. PMID 11076738. Retrieved 7 June 2023.
40. Lind, Olle; Mitkus, Mindaugas; Olsson, Peter; Kelber, Almut (15 May 2013). "Ultraviolet sensitivity and colour vision in raptor foraging". Journal of Experimental Biology. 216 (10): 1819–1826. doi:10.1242/jeb.082834.

Further reading

• Brown, Leslie (2013). British birds of prey : a study of Britain's 24 diurnal raptors. Hammersmith, London: HarperCollins Publishers. ISBN 9780007406487.
• Dunne, Pete; Karlson, Kevin (2017). Birds of Prey Hawks, Eagles, Falcons, and Vultures of North America. Houghton Mifflin Harcourt. ISBN 9780544018440. OCLC 953709935.
• Macdonald Lockhart, James (2017). Raptor : a journey through birds. Chicago: The University of Chicago Press. ISBN 9780226470580. OCLC 959200538.
• Mackenzie, John P. S. (1997). Birds of prey. Toronto, Ont: Key Porter Books. ISBN 9781550138030. OCLC 37041161.
• Newman, Kenneth (1999). Kenneth Newman's birds of prey of southern Africa : rulers of the skies : an identification guide to 67 species of southern African raptors. Knysna, South Africa: Korck Pub. ISBN 978-0620245364. OCLC 54470834.
• Olsen, Jerry 2014, Australian High Country raptors, CSIRO Publishing, Melbourne, ISBN 9780643109162.
• Remsen, J. V. Jr., C. D. Cadena, A. Jaramillo, M. Nores, J. F. Pacheco, M. B. Robbins, T. S. Schulenberg, F. G. Stiles, D. F. Stotz, and K. J. Zimmer. [Version 2007-04-05.] A classification of the bird species of South America. American Ornithologists' Union. Accessed 2007-04-10.
• Yamazaki, Tour (2012). Field guide to Raptors of Asia. London: Asian Raptor research and Conservation Network. ISBN 9786021963531. OCLC 857105968.

External links

• with The Peregrine Fund
• Explore Birds of Prey on the Internet Bird Collection
• Bird of Prey Pictures
• Global Raptor Information Network
• Raptor Resource Project