441

CAYENNE [SOUTHERN] LAPWING  Vanellus [chilensis] cayennensis (p. 62). Differences in morphology,

plumage, and vocalizations indicate that the widespread cayennensis group (S America, spreading to Cen-

tral America) and allopatric chilensis group (Chile and s. Argentina; Chilean Lapwing) are best considered

separate species.

WHIMBREL  Numenius phaeopus (p. 66). Species status has been argued for New World populations

(hudsonicus group, Hudsonian Whimbrel), based largely on genetic data (Sangster et al. 2011); although

Hudsonian Whimbrel is split by IOC, in our view the case remains unproven from a biological perspective.

WILLET  Tringa semipalmata (p. 68). Differences in ecology, morphology, plumage, and voice (supported

by molecular evidence; Oswald et al. 2016) indicate that the inornata group (breeding interior w. N

America; Western Willet) and semipalmata group (breeding coastal e. N America; Eastern Willet) are

probably best treated as separate species.

AMERICAN GREAT EGRET  Ardea [alba] egretta (p. 78). Differences in morphology, seasonal bare-part

coloration, and provisionally in voice indicate that the egretta group (Americas) is best treated as a species

distinct from Old World populations.

BOAT-BILLED HERON  Cochlearius cochlearius (p. 82). Differences in plumage coloration, crest length

of breeding birds, and provisionally in voice (averages higher, more chuckling in Northern), suggest that

the zeledoni group (Middle America; Northern Boat-billed Heron) and cochlearius group (S America;

Southern Boat-billed Heron) may represent separate species.

LIMPKIN  Aramus guarauna (p. 88). Differences in plumage and provisionally in voice suggest the pictus

group (s. to w. Panama; Northern Limpkin) and guarauna group (cen. Panama to S America; Southern

Limpkin) may represent separate species.

NORTHERN SUNBITTERN  Eurypyga [helias] major (p. 100). Differences in plumage and voice suggest

that the major group (Central America to Andes, including e. Andean meridionalis) and helias group

(lowland S America; Amazonian Sunbittern) represent separate species (Howell & Dyer 2022).

NORTHERN TURKEY VULTURE  Cathartes [aura] aura (p. 112). Differences in morphology, plumage,

and bare-part coloration indicate that Turkey Vulture complex comprises at least 3 groups and at least

2 species: Northern Turkey Vulture (Mexico to Costa Rica); Tropical Turkey Vulture C. [a.] ruficollis

(Panama to tropical S America); and the distinctive Austral Turkey Vulture C. [a.] jota (Andes and s. S

America, including falklandicus). An undescribed form (shown on plate) occurs from Costa Rica to n. S

America, perhaps an intergrade population between Northern and Tropical; study needed.

NORTHERN WHITE HAWK  Pseudastur [albicollis] ghiesbreghti (p. 126). Differences in voice and

morphology indicate that the ghiesbreghti group (Mexico to nw. S America) and superciliaris group (S

America, e. of the Andes; Southern White Hawk) are separate species; also see Lerner et al. (2008).

OSPREY  Pandion haliaetus (p. 142). Wink et al. (2004) argued that all 3 Osprey taxa they studied (of

4 worldwide) warranted species status, based purely on mitochondrial DNA lineages, whereas Monti et

al. (2015) provided a conflicting molecular interpretation based again purely on mitochondrial DNA.

Although IOC and others have adopted a two-way split (Western Osprey P. [h.] haliaetus vs. Eastern

Osprey P. [h.] cristatus), we see no biological evidence that offers compelling support for this; a 4-way

species split seems equally valid, or all taxa might be maintained as a single species.

NORTHERN MOTTLED OWL  Strix [virgata] virgata (p. 146). Differences in voice and morphology

indicate that the virgata group (Mexico to nw. Peru) and superciliaris group (S America, e. of the Andes;

Amazonian Mottled Owl) are best treated as separate species. Also see Sanchez et al. (2012).

COSTA RICAN [VERMICULATED] SCREECH OWL  Megascops [guatemalae] vermiculatus and

SKUTCH’S [VERMICULATED] SCREECH OWL Megascops [guatemalae] undescribed (p. 148). Given

morphological and vocal differences comparable to those between other accepted species of screech owls,

we recognize 5 species of ‘Vermiculated Screech Owl’ in Middle America, 2 of them in Costa Rica: Costa

Rican Screech Owl (e. Nicaragua to nw. Panama) and the formally undescribed Skutch’s Screech Owl,

from the Pacific slope of Costa Rica (and w. Panama?); on the basis of voice, Skutch’s Screech Owl is allied

to Choco Screech Owl and is treated within that species by eBird.

FERRUGINOUS PYGMY OWL  Glaucidium brasilianum (p. 148). Vocal and slight morphological and

plumage differences suggest that the ridgwayi group (Mexico to nw. Colombia; Ridgway’s Pygmy Owl)