Taxonomy and systematics
The osprey was one of the many species described by
Carl Linnaeus in his 18th-century work,
Systema Naturae, and named as Falco haliaeetus.
 The genus, Pandion, is the sole member of the family Pandionidae, and used to contain only one species, the osprey (P. haliaetus). The genus Pandion was described by the French zoologist
Marie Jules César Savigny in 1809.
Most taxonomic authorities consider the species cosmopolitan and conspecific. A few authorities split the osprey into two species, the western osprey and the
The osprey differs in several respects from other
diurnal birds of prey. Its toes are of equal length, its
tarsi are reticulate, and its talons are rounded, rather than grooved. The osprey and owls are the only raptors whose outer toe is reversible, allowing them to grasp their prey with two toes in front and two behind. This is particularly helpful when they grab slippery fish.
 It has always presented something of a riddle to taxonomists, but here it is treated as the sole
living member of the family Pandionidae, and the family listed in its traditional place as part of the order
Other schemes place it alongside the hawks and eagles in the family
Accipitridae—which itself can be regarded as making up the bulk of the order
Accipitriformes or else be lumped with the
Sibley-Ahlquist taxonomy has placed it together with the other diurnal raptors in a greatly enlarged
Ciconiiformes, but this results in an unnatural
Australasian subspecies is the most distinctive
Californian bird with scraps of fish on its beak
The osprey is unusual in that it is a single living species that occurs nearly worldwide. Even the few
subspecies are not unequivocally separable. There are four generally recognised subspecies, although differences are small, and
ITIS lists only the first two.
- P. h. haliaetus – (
- P. h. carolinensis – (
North America. This form is larger, darker bodied and has a paler breast than nominate haliaetus.
- P. h. ridgwayi –
Caribbean islands. This form has a very pale head and breast compared with nominate haliaetus, with only a weak eye mask.
 It is non-migratory. Its scientific name commemorates American
- P. (h.) cristatus – (
Vieillot, 1816): coastline and some large rivers of
Tasmania. The smallest and most distinctive subspecies, also non-migratory.
 (most taxonomists continue to consider this a subspecies. A few authorities have given it full species status
 as the
To date there have been two
extinct species named from the fossil record.
Pandion homalopteron was named by
Stuart L. Warter in 1976 from fossils of
Barstovian age, found in marine deposits in the southern part of
California. The second named species
Pandion lovensis, was described in 1985 by
Jonathan J. Becker from fossils found in
Florida and dating to the
latest Clarendonian and possibly representing a separate lineage from that of P. homalopteron and P. haliaetus. A number of claw fossils have been recovered from Pliocene and Pleistocene sediments in Florida and
The oldest recognized family Pandionidae fossils have been recovered from the Oligocene age
Jebel Qatrani Formation, of
Egypt. However they are not complete enough to assign to a specific genus.
 Another Pandionidae claw fossil was recovered from
Early Oligocene deposits in the
Germany, and was described in 2006 by
The genus name Pandion derives from the
king of Athens and grandfather of
Pandion II. Although Pandion II was not used to name a
bird of prey,
Nisus, a king of
Megara, was used for the genus.
 The species name haliaetus comes from
Ancient Greek haliaietos ἁλιάετος
 from hali- ἁλι-, "sea-" and aetos άετος, "eagle".
The origins of osprey are obscure;
 the word itself was first recorded around 1460, derived via the
Anglo-French ospriet and the
Medieval Latin avis prede "bird of prey," from the
Latin avis praedæ though the
Oxford English Dictionary notes a connection with the
Latin ossifraga or "bone breaker" of
Pliny the Elder.
 However, this term referred to the