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Grallaria ridgelyi

Jocotoco Antpitta

  • Order: Passeriformes
  • Family: Grallariidae
  • Monotypic

Authors: Greeney, Harold F

Identification

Summary

Jocotoco Antpitta shares the long-legged, plump-bodied, tailless silhouette of its congeners. Sexes are similar in this species, both having a black cap and the rest of the upperparts brownish olive. The throat is bright white as are most of the lower parts, becoming more washed with light gray lower down. The breast is light gray; the flanks and sides of the breast are gray, washed with olive brown. The most striking featureof Jocotoco Antpitta is the large, bright white patch in front of the eye which extends from the preloral area down to below the eye and onto the anterior portion of the auriculars.

Similar Species

This very large antpitta is striking and unmistakable. The somewhat similar Pale-billed Antpitta (Grallaria carrikeri) is smaller, has a pale bill, a black throat, is dark gray below, and lacks the white face marking of Jocotoco Antpitta. Pale-billed Antpitta also does not overlap geographically with Jocotoco Antpitta. The sympatric Chestnut-naped Antpitta (Grallaria nuchalis) immediately is distinguished from Jocotoco by lacking white on the face or throat and by having a rufous crown.

Vocalizations

The song of Jocotoco Antpitta is a slow series of 6-10 (or more) identical notes produced at 0.5-0.6 kHz, and delivered at 1-2 second intervals (Krabbe and Schulenberg 2003). The aforementioned authors suggest that the song of Jocotoco Antpitta is reminiscent of a dog, but my own description would perhaps be more like the distant moo of a cow.

The call is a similarly low, but much softer two-noted ho-co. In alarm both sexes give a similar call, but louder in volume and the second part may be more emphatic and almost double-noted, sometimes ending in a harsh churr and described as a hoó-krrr or a staccato hoó-có-kurr (Krabbe et al. 1999, Heinz 2002, Ridgely and Tudor 2009). These calls are the inspiration for the species’ common name, which is the local onomatopoeic rendition of this jóco-tó-cuorrr. Juveniles make what is apparently a contact call while foraging near adults, as suggested by Heinz (2002). It is described as a slightly drawn-out, single woooo note, easily imitated with a whistle, which is similar in quality to a single note of the common song of Ferruginous Pygmy-owl (Glaucidium brasilianum) (Greeney and Gelis 2005).

Additional audio recordings of vocalizations of Jocotoco Antpitta can be heard at Macaulay Library, at xeno-canto, and at Internet Bird Collection.

Nonvocal Sounds

Agitated adults, while bobbing their heads and running back and forth, make a whooshing sound or subdued clap as they simultaneously flick their wings (personal observations).

Detailed Description (appearance)

Adult – Sexes similar. The original species diagnosis of Jocotoco Antpitta by Krabbe et al. (1999) is as follows:

"A large antpitta (body mass 150 to 200 g) assignable to the genus Grallaria. Separable from known antpittas by white cheek patch of rigid loose-barbed feathers with glossy shafts extending from the subocular and posterior part of the lower lores to the base of the bill. The white cheek patch contrasts sharply with the black cap, bill malar region, and anterior auricular feathers. The new species differs from all other Grallaria in lacking true rictal bristles. The throat feathers are white, stiff, and loose-barbed, as in the Ochre-striped Antpitta (G. dignissima), but are denser, shorter, and with more recurved tips, as in Chestnut-naped Antpitta (G. nuchalis). The gray of the underparts is interspersed with white in a pattern resembling pale-bellied members of the G. hypoleuca allospecies group. The bill is shaped most like that of G. nuchalis and the Pale-billed Antpitta (G. carrikeri) but is proportionately deeber at the base and with a straighter culmen. Tarsi and toes proportionately large than in other antpittas and as large as in Giant Antpitta (G. gigantea). Tarsal scutes few and distinctly ridged with toes and claws short and study, resembling G. nuchalis."

Using color designations from Smithe (1975), Krabbe et al. (1999) describe the holotype (adult male) as: "Crown, a 1 to 2-mm wide feathered ocular ring, broad malars, and anterior auriculars connecting with malars Jet Black. A large and distinct fan-shaped patch of rigid, loose-barbed white feathers with glossy shafts in the loral and sub-ocular region. These feathers are longer and denser than in congeners and cover the base of the bill and most of the malar region. Rictal bristles lacking, but a few of the white loral feathers have elongated bare shafts, forming bristle-like extensions. Poorly defined postocular streak, posterior part of auriculars, and sides of neck Light Neutral Gray, Nape black but suffused with color of back, which is closest to Brownish Olive, but more golden. Upper mantle with black wash that decreases posteriorly. All back feathers with blackish shafts. Tail, composed of 12 rectricies, between Raw Umber and Mars Brown. The three innermost secondaries and outer webs of the nine other secondaries slightly lighter than Chestnut. The distal half of the outer webs of the 10 primaries are Ground Cinnamon, the inner webs of the remiges are blackish, and the underwing primary coverts are mostly black. Upperwing coverts Brownish Olive with 2-mm wide blackish band. Alula Brownish Olive like back, outer webs nearly uniform. Breast White with light suffusion of Light Neutral Gray. Throat white, feathers fairly stiff, glossy, elongated and recurved shafts that on some chin feathers are distinctly dark-tipped. Feathers of upper breast with faint, blackish, about 1-mm wide terminal suffusions. Crissum and extreme lower belly washed with Pale Pinkish Buff. Sides of breast Brownish Olive. Sides and flanks Light Neutral Gray suffused with Brownish Olive. Thighs Brownish Olive admixed with Light Neutral Gray and heavily washed with black. Undertail coverts and underwing coverts Brownish Olive, with fine black bars. A single completely black feather is on the left shoulder, a nearly black one on the right thigh, and most of the olive-brown feathers have faint blackish tips. In life, the bill is jet black, the irides are crimson reddish brown, and the tarsi and toes are blue-gray."

Juvenile – Similar in patterning to adults, but with the throat white, the upper to lower breast pale slate-gray and fading to whitish on the belly. The distinctive malar pattern of adults is evident, but more subdued. The most distinctive difference is the chestnut (rather than black) crown, bearing fine black vermiculations that extend onto the hindcrown and fade gradually onto the nape, just reaching the upper back. The primaries are chestnut, as in the adult, and tertials bear indistinct, subterminal black bands. The bill is black, except for the basal two-thirds of the lower mandible, which is fleshy orange. The iris is dull red or red-brown, but otherwise the soft-part coloration is similar to adults (Greeney and Gelis 2005). Tobias (2009) includes a photograph of a juvenile similar to this description.

Bare Parts

Iris: dark red, crimson reddish brown

Bill: black

Tarsi and toes: blue gray

Measurements

Total length: 20-22 cm (Krabbe and Schulenberg 2003, Restall et al. 2006), 23 cm (Ridgely and Greenfield 2001, Ridgely and Tudor 2009).

Linear measurements:

Males – Unflattened wing chord 130 mm; flattened wing chord 138 mm; tail 59.6 mm; bill at nares 19.3 mm; bill from skull 33.5 mm; tarsus 67.1 mm (n = 1; holotype, adult male, Krabbe et al. 1999).

Unflattened wing chord, mean 131 ± 3.61 mm (range 128-135 mm); flattened wing chord, mean 138 ± 2.52 mm (range 135-140 mm); tail, mean 58 ± 2.43 mm (range 55-66 mm); exposed culmen, mean 28.2 ± 1.0 mm (range 27.1-29.0 mm); bill at nares, mean 19.5 ± 0.85 mm (range 18.9-20.5 mm); bill from skull, mean 34.8 ± 1.63 mm (range  33.5-36.6 mm); bill width at base, mean 16.1 ± 1.01 mm (range 15-17 mm); tarsus, mean 71.1 ± 3.59 mm (range 67.1-74.1 mm); middle toe, mean 47.1 ± 1.91 mm (range 46.0-49.3 mm); hind claw, mean 13.9 ± 0.25 mm (range 13.6-14.1 mm) (n = 3 adult males from type series, including holotype; Krabbe et al. 1999).

Females – Unflattened wing chord 124 mm, 128 mm; flattened wing chord 131 mm, 133 mm; tail 50 mm, 57 mm; exposed culmen 27.0 mm, 28.5 mm; bill at nares 18.1 mm, 18.6 mm; bill from skull 32.9 mm, 33.1 mm; bill width at base 15.8 mm, 16.2 mm; tarsus 67.4 mm, 73.4 mm; middle toe 45.4 mm, - mm; hind claw 13.62 mm, 14.0 mm (n = 2 adult females from type series; Krabbe et al. 1999).

Mass: 176 g (male holotype; Krabbe et al. 1999); mean 192 ± 14.3 g, range 176-204 g (n = 3 adult males from type series, including holotype; Krabbe et al. 1999); 152 g, 182 g (n = 2 adult females from type series; Krabbe et al. 1999).

Molts

No specific information.

Geographic Variation

Grallaria ridgelyi is monotypic.

Systematics

Described as Grallaria ridgelyi Krabbe, Agro, Rice, Jacome, Navarrete, and Sornoza M. 1999, with type locality of 2520 m, Quebrada Honda, Zamora-Chinchipe Province, southeastern Ecuador. The scientific name for Jocotoco Antpitta is in honor of Robert S. Ridgely.

Jocotoco Antpitta is thought to be most closely related to Chestnut-naped Antpitta (Grallaria nuchalis) and Pale-billed Antpitta (Grallaria carrikeri), with these three species possibly forming a sister clade to Chestnut-crowned Antpitta (Grallaria ruficapilla) and Watkins's Antpitta (Grallaria watkinsi) (Krabbe et al. 1999, Krabbe and Schulenberg 2003).

Recommended Citation

Greeney, Harold F. 2013. Jocotoco Antpitta (Grallaria ridgelyi), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=404361