Bicolored Hawk (Accipiter bicolor) is a separate species, resident to Central
and South America.
Jeff is probably referring to the "white breasted" Group of Sharp-shinned Hawk
(Accipter striatus) which occurs in Mexico and Central America though the
"rufous-thighed" Group of South America is also referenced.
The point is that it is a VERY cool sighting north of the wall (Game of Thrones
reference). Not quite as exciting as the 1st state record of Dusky Thrush (11
day cold trail aside), but still pretty exciting.
Cheers,
Russ Namitz
PS: Just a quick note for those unfamiliar with how to read scientific name
abbreviations.
Accipiter striatus is the scientific name for the species of Sharp-shinned Hawk.
Accipiter striatus chionongaster is the scientific name for a particular
subspecies of Sharp-shinned Hawk and, once referenced, will be written as A. s.
chionongaster.
*******************************************************************
White-Breasted Hawk (Chionogaster Group).
One subspecies. Storer (Storer
1952b<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF19896>)
interpreted a cline in pattern and color of underparts toward paler,
relatively unmarked populations in s. Mexico (madrensis) as a bridge to the
white underparts of chionongaster and therefore lumped this taxon with other
Sharp-shinned Hawk forms to the north. Also, because chionogaster was in the
past regarded as a race of erythronemius (along with ventralis) of South
America (e.g., Hellmayr and Conover
1949<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF21593>),
Storer (Storer
1952b<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF19896>)
believed all taxa should be merged under striatus . Monroe (Monroe
1968<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF57425>)
disagreed with this view and regarded all these taxa as separate species.
A. s. chionogaster Kaup, 1852: Chiapas, Mexico, south to Nicaragua. Smaller
than other Mexican subspecies. Adults with upperparts sooty (head) to fuscous
black; underparts white, with prominent blackish shaft streaks on chin, throat,
and breast; tibial feathering unmarked, light ochraceous-buff.
Rufous-Thighed Hawk (Erythronemius Group).
Two subspecies, each sometimes regarded as distinct species (e.g., Sibley and
Monroe
1990<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF64578>,
Bierregaard
1994<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF48420>).
A. s. ventralis Sclater, 1866: Resident of Andean w. Venezuela, Colombia, and
w. Bolivia. Highly variable, ranging from very pale below to heavily barred,
with some melanism, the latter possibly restricted to males (Hellmayr and
Conover
1949<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF21593>,
but see Wattel
1973<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF8598>).
Distinguished from both velox and chionogaster by deep rufous, reddish
chestnut, or cinnamon brown (Smithe
1975<https://birdsna.org/Species-Account/bna/species/shshaw/references#REF61281>:
color no. 33) tibial feathers; lighter on belly than on throat and breast;
dark tail bands broader than paler bands.
A. s. erythronemius Kaup, 1850: Resident e. Bolivia, s. Brazil, Paraguay,
Uruguay, and n. Argentina. Similar to ventralis but ventral barring, when
present, more prominent and upperparts more uniform and darker (back almost
entirely slaty black or fuscous brown); somewhat smaller than ventralis .
