Bearded Screech-Owl Megascops barbarus

  • Order: Strigiformes
  • Family: Strigidae
  • Monotypic
  • Authors: Paula L. Enríquez
Sections

Appearance

Distinguishing Characteristics

The Bearded Screech-Owl is a Megascops with yellow irides, relatively short "ear" tufts, and a scalloped pattern on the underparts. It is strictly nocturnal.

Similar Species

The distribution of the Whiskered Screech-Owl (Megascops trichopsis) overlaps the distribution of the Bearded Screech-Owl in Chiapas and Guatemala. The plumage of the Whiskered Screech-Owl is very similar to that of Bearded, but the two species can be identified by vocalization. The Bearded Screech-Owl also has more conspicuous whitish "eyebrows," is smaller and the toes are pink and naked (unfeathered).

Detailed Description

The Bearded Screech-Owl is relatively small, with short, difficult-to-see "ear" tufts. Coronal band well marked. Body feathers are brown with white and black spots; lower parts are white with brown and yellow lines. Wing feathers have a white spot at the end. Wings project beyond tail. Tarsus are feathered until finger base, those are naked and pinkish (Howell y Web 1995, Enríquez 2006). This species shows two different plumage color morphs: dark (reddish) and pale (gray-brown) (Peterson and Chalif 1973). Owls captured in Chiapas had both plumage types; five of eight females and one of six males had reddish plumage. Three specimens collected in Guatemala which one female was reddish and the other two specimens of undetermined sex were a mix of gray-brown and red (D. James personal communication, from National Museum of Natural History; USNM).

Juveniles are barred brown and yellow.

For a very detailed description of the plumage, see Ridgway (1914: 723).

Molts

Molt is after the breeding season, in the rainy season (July to October; n=12). July is the peak of the molt, with owls (n=8) showing molt throughout the body. Flight feathers molt two at the same time in ascendant order and simultaneously in both wings. Secondary feathers molt at the same time and similar to primary feathers (Enríquez and Cheng 2008). Similar to other owl species, rectrices molt partially (gradual or irregular) or complete (Forsman 1981). Two individuals were molting throughout the body but also all rectrices were in molt. Fat was obvious all year, but was more evident in dry season (December- March; Enríquez and Cheng 2008).

Bare Parts

Iris: yellow.

Bill: greenish

Toes: unfeathered, pink

Data from Howell and Web (1995), del Hoyo et al. (1999), Enríquez (2006).

Measurements

Owls show reversed sexual dimorphism in size: females are larger than males (linear measurements and mass). Female Bearded Screech-Owls are 72 ± 1.72 g (n=8) and males are 63 ± 1.89 g (n= 5; t = -3.35, P < 0.01). Rectrices are longer in females (63.6 ± 0.17 mm) than in males (61.6 ± 0.40 mm; t= -5.14, P <0.01). Wing length (female 137.1 mm; male 134.9 mm), tarsus length (female 29.9 mm; male 30 mm), culmen length (female 14.4 mm; male 15.2 mm) and keel (female 22.2 mm; male 22.1 mm) do not vary between the sexes (Enríquez 2007, Enríquez and Cheng 2008). Sexual dimorphism also shows females are bigger in body mass than males (SDI SDIbody mass = 4.47), but with a culmen shorter than males (SDIculmen = - 4.36).

Recommended Citation

Enríquez, P. L. (2011). Bearded Screech-Owl (Megascops barbarus), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.besowl.01