Sea eagle
A sea eagle or fish eagle (also called erne or ern, mostly in reference to the white-tailed eagle) is any of the birds of prey in the genus Haliaeetus[2] in the bird of prey family Accipitridae.
The genus Haliaeetus was introduced in 1809 by French naturalist Marie Jules César Savigny in his chapter on birds in the Description de l'Égypte.[3][4] The two fish eagles in the genus Ichthyophaga were found to lie within Haliaeetus in a genetic study in 2005,[5] they were then moved accordingly. They are very similar to the tropical Haliaeetus species. A prehistoric (i.e. extinct before 1500) form from Maui in the Hawaiian Islands may represent a species or subspecies in this genus.
The relationships to other genera in the family are less clear; they have long been considered closer to the genus Milvus (kites) than to the true eagles in the genus Aquila on the basis of their morphology and display behaviour;[6][7] more recent genetic evidence agrees with this, but points to their being related to the genus Buteo (buzzards/hawks), as well, a relationship not previously thought close.[8]
A 2005 molecular study found that the genus is paraphyletic and subsumes Ichthyophaga, the species diverging into a temperate and tropical group.[9]
Haliaeetus is possibly one of the oldest genera of living birds. A distal left tarsometatarsus (DPC 1652) recovered from early Oligocene deposits of Fayyum, Egypt (Jebel Qatrani Formation, about 33 million years ago (Mya)) is similar in general pattern and some details to that of a modern sea eagle.[10] The genus was present in the middle Miocene (12-16 Mya) with certainty.[11]
The origin of the sea eagles and fishing eagles is probably in the general area of the Bay of Bengal. During the Eocene/Oligocene, as the Indian subcontinent slowly collided with Eurasia, this was a vast expanse of fairly shallow ocean; the initial sea eagle divergence seems to have resulted in the four tropical (and Southern Hemisphere subtropical) species living around the Indian Ocean today. The Central Asian Pallas's sea eagle's relationships to the other taxa is more obscure; it seems closer to the three Holarctic species which evolved later and may be an early offshoot of this northward expansion; it does not have the hefty yellow bill of the northern forms, retaining a smaller, darker beak like the tropical species.[8]
