_Haliaëtus_, SAVIG. 1809. (Type, _Falco albicilla_, LINN.)
_Thalassoaëtus_, KAUP, 1844. (Type, _Falco pelagicus_, PALLAS.)
_Cuncuma_, HODGSON, 1837. (Type, _Falco macei_, TEMM.)
_Pontoaëtus_, KAUP, 1844. (Same type.)
_Blagrus_, BLAS. 1849. (Same type.)
_Polioaëtus_, KAUP, 1847. (Type, _Falco icthyaëtus_, HORSF.)
_Icthyiaëtus_, LAFR. 1839 (nec KAUP, 1829). (Same type.)
GEN. CHAR. Form robust, and organization powerful, as in _Aquila_; size
large. Bill very large, usually somewhat inflated, the chord of the arch
of the culmen more than twice the length of the cere on top; commissure
with a more or less distinct festoon and sinuation behind it. Nostril
oval, obliquely vertical. Feet robust and strong, the tarsus less than
one and a half times the middle toe; tarsus feathered in front and on
the sides for about one half its length; front of the tarsus and top of
the toes with an imperfectly continuous series of transverse scutellæ,
entirely interrupted in the region of the digito-tarsal joint; the other
portions covered with roundish, somewhat granular, scales, these larger
on the posterior face. Claws large, strongly curved, and more obtuse,
and less graduated in size, than in _Aquila_. No trace of a web between
outer and middle toes. Wing very large, the primaries well developed and
strong; third to fifth quill longest; first longer than the ninth; outer
five to six with inner webs deeply emarginated. Tail variable in length
and shape, usually short and rounded, cuneate and with fourteen feathers
in _H. pelagicus_, and nearly even, and with twelve feathers, in _H.
macei_, the rest all having twelve feathers, varying in form with the
species. Feathers of the neck, all round, lanceolate.
The species of this very strongly marked genus vary between great
extremes in the details of their external structure; but these
variations I consider to be mainly specific, though two well-defined
subgeneric divisions should be made, one to include the Old World _H.
leucogaster_, _H. vocifer_, and _H. icthyætus_, which have five, instead
of six, outer quills, with their inner webs cut, and the tarsus with the
frontal and posterior rows of broad transverse scutellæ nearly as well
developed and continuous as in _Buteo_. The last of these species has
the claws nearly uniform in size, and contracted and rounded underneath
almost as much as in _Pandion_; but the other species are less so, each
differing in this respect, so that I consider this as only indicating
the greatest perfection in the specialization of the piscatorial type
of modified structure. In the possession of fourteen tail-feathers, its
very large bill, naked lores, and general aspect, the _H. pelagicus_
shows an approach to the Old World Vultures.
About nine species are known, of which only two belong to North America,
one of them (_H. leucocephalus_) being peculiar to that continent.
Tropical America is without a single representation of the genus.
The majority of the species belong to the Indian region, only the
_H. albicilla_ and _H. pelagicus_ belonging to the Palæarctic Realm,
the former representing the western, and the latter peculiar to the
eastern, district of that zoögeographical division; it is the former
which straggles into the Nearctic fauna. The habits of the Sea Eagles
differ considerably from those of the true Eagles (_Aquila_) in very
important respects; they frequent the shores of the sea, lakes, or large
rivers, instead of mountainous portions, and feed chiefly—some of the
species entirely—on fish. Those of the subgenus _Polioaëtus_ are almost
precisely like _Pandion_ in their habits.
[Illustration:
=52509=,♀ ? ¼
=9128=,♀. ¼
=9128=,♀. ¼
=28100.=(♀ ?) ¼
=9128=,♀ ? ¼
52509 : 9128. _Haliaëtus leucocephalus._
28100. _H. pelagicus._]
The three closely allied species belonging to the northern portions of
the Northern Hemisphere may be distinguished by the characters given in
the following synopsis.
Species and Races.
COMMON CHARACTERS. _Adult._ Bill, cere, and iris yellow. Tail, and
sometimes the head and neck, white. _Young._ Bill and cere black; iris
dark brown. Tail, head, and neck, blackish.
[Illustration:
=28100=,(♀ ?). NAT. SIZE.
=28100=,(♀ ?). ¼
_Haliaëtus pelagicus._]
=A.= Tail of fourteen feathers, cuneate, or graduated, for nearly
half its length. Nostril with its lower end acute, bevelled
gradually to the level of the cere; upper outline of the cere very
convex; lore naked.
1. =H. pelagicus.=[93] Wing, 24.50–26.00; tail, 13.50–16.00;
culmen, 2.60; depth of bill, 1.80; cere, on top, 1.10; tarsus,
3.50; middle toe, 2.95. _Adult._ Forehead, greater wing-coverts,
abdomen, and tail, white; other portions blackish-brown (AUCT.).
_Young._ Dark umber or blackish-brown, the feathers of the head
and neck with lighter shaft-streaks; tertials (except at ends)
and basal third, or more, of inner webs of tail-feathers, white;
tail-coverts much mixed with the same. _Hab._ Northeastern Asia.
=B.= Tail of twelve feathers, only slightly rounded. Lower end of
the nostril rounded, opening more abruptly inward; upper outline of
the cere nearly straight; lores scantily feathered.
2. =H. albicilla.= Wing, 23.00–28.00; tail, 11.50–16.00; culmen,
2.05–2.20; tarsus, 3.30–3.80; middle toe, 2.50–2.95; depth of
bill about 1.45; cere, on top, .85. _Adult._ Head and neck pale
grayish-fulvous, or dirty yellowish-gray, not abruptly lighter
than the body. Tail, only, pure white. Rest of the plumage,
including the tail-coverts, dark grayish-brown, inclining to
blackish on the primaries. _Young._ Prevailing tint of the upper
parts light isabella-color, or pale grayish-cinnamon, each feather
having a terminal triangular spot of blackish-brown. Breast soiled
white, with broad stripes of brownish-black; rest of the lower
parts nearly uniform fulvous-brown, the tibiæ darker. _Hab._
Europe; Egypt; Greenland.
3. =H. leucocephalus.= Wing, 20.00–26.00; tail, 10.50–15.50;
culmen, 1.85–2.20; tarsus, 2.65–3.70; middle toe, 2.35–3.10; depth
of bill about 1.30; cere, on the top, .80. _Adult._ Head and
neck, tail and tail-coverts, pure white, immaculate (except in
transition dress). Rest of the plumage brownish-black. _Young._
Brownish-black, showing much concealed white at the bases of the
feathers; ground-color inclining to umber-brown on the upper
surface; on the lower parts, the basal white much exposed and
predominating, the blackish forming longitudinal, tear-shaped
spots. Head and neck brownish-black, the penicillated feathers of
the nape seldom with whitish points. Tail-feathers and primaries
black, the inner webs usually more or less marked, longitudinally,
with buffy-whitish. _Hab._ The whole of North America.
SP. CHAR. _Young female_(?) (28,100, Amoor River; Mr. Burlingame).
Form: very similar to _H. albicilla_ and _H. leucocephala_, but bill
altogether more robust, and feet rather less so, than in these. Tail, of
fourteen feathers! graduated for about one half its length. Dimensions:
About the size of the female of the two other species. Color: Generally
dusky vandyke-brown, a medial line on the lanceolate feathers of the
neck, and the border of the squamate ones of the tibiæ, decidedly
lighter. Entire plumage white at the base, this exposed wherever the
feathers are disarranged, and prevailing on the crissum. Tertials, basal
half of inner webs of primaries, the whole tail, and upper tail-coverts,
white with a yellowish tinge. Tertials, upper tail-coverts, and
tail-feathers, with a large terminal spot of clear grayish-black; on the
tail these form a rather irregular terminal zone, being on the middle
feather narrower, and broken into fine blotches. Bill, cere, lore, and
feet, yellow; end of upper mandible, and the claws, black. Wing-formula,
3, 4, 2, 5–6–7=1. Wing, 24.50; tail, 13.50; culmen, 2.60; depth of bill,
1.80; cere, on top, 1.10; tarsus, 3.50; middle toe, 2.95.
Haliaetus albicilla (LINN.).