Fr: Gobemoucheron masqué
All : Maskenmückenfänger
Esp : Perlita Enmascarada
Ital : Zanzariere mascherato
Nd: Markermuggenvanger
Sd: Maskmyggsnappare
Port: Balança-rabo-de-máscara
Photographers:
Marc Chrétien
MURINUS
Philippe et Aline Wolfer
GALERIE
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD Vol 11 by Josep del Hoyo, Andrew Elliott and David Christie - Lynx Edicions - ISBN: 849655306X
BirdLife International (BirdLife International)
The Cornell Lab of Ornithology – Neotropical birds
Wikipedia, the free encyclopaedia
Masked Gnatcatcher
Polioptila dumicola
Passeriforme Order – Polioptilidae Family
BIOMETRICS:
Length: 12-13 cm
Weight: 5-7 g
DESCRIPTION:
The Masked Gnatcatcher is a small South American songbird, always very active when foraging for insects, hopping, hovering and gleaning upside down in the vegetation.
This bird is the largest species of genus Polioptila.
The male adult of nominate race has blue-grey forehead, crown, nape and upperparts. On the wings, the flight feathers are blackish with white-edged secondaries. The tail is black with white outer rectrices.
On the underparts, chin and throat are pale grey, becoming whiter towards belly and undertail-coverts.
The male shows a conspicuous black mask from the base of the upper mandible, through the eye and back to ear-coverts. We can see a narrow, white stripe bordering the lower edge of the mask.
Bill, legs and feet are blackish. The eyes are dark brown.
The adult female is almost similar but she lacks the black mask. She has a black border from behind the eye to the rear of the white ear-coverts. The eyes are surrounded by narrow white eye-ring. Her plumage is duller, less blue-grey than in male.
We can find three subspecies:
P.d. dumicola (here described), is found in E Bolivia, Paraguay and S Brazil, S to E Argentina and Uruguay.
P.d. berlepschi is found in C Brazil. The male is paler with dull grey mantle and narrower black mask. The female is paler overall.
P.d. saturata is found in the highlands of Bolivia. This one is darker than nominate, with slate-grey crown, upperparts and underparts.
VOICE: SOUNDS BY XENO-CANTO
The Masked Gnatcatcher of nominate race utters a variable, short, sweet and musical song, a continuous phrase repeated while foraging “suwee, tu-tu-tu-tu”, or “tuawee ti-ti-ti-ti”, or “wit, wit, wit…” and other variations.
The race “berlepschi” gives repeated sequences of descending notes “dlééew” and other variable sequences.
Contact and alarm calls are described as “grehl” and “tserét-greh”.
They sing while standing erect.
HABITAT:
The Masked Gnatcatcher of nominate race occurs in several types of habitats such as Chaco (dry arid habitat with thorny bushes and cacti), Humid Chaco (several ecosystems such as woods with savannas), and Cerrado (vast tropical savanna). This race occurs mostly below 1000 metres of elevation.
The race “berlepschi” is found in Cerrado and Pantanal (wide humid area) areas, mainly with tree cover without continuous canopy.
The race “saturata” occurs in montane dry forest in Bolivia, between 1500-2000 metres of elevation.
RANGE:
See above in “subspecies”.
BEHAVIOUR:
The Masked Gnatcatcher feeds on small arthropods. This is a very active foraging bird, searching for preys in tree canopy. It regularly hops on branches while foraging on foliage. To feed, it gleans, and then performs hover-gleaning. It also makes rapid sallies and sometimes probes into the bark crevices.
As other Polioptilidae species, this bird is always on the move. It flicks wings and tail while foraging. The cocked tail is moved from side to side.
It sunbathes every day and preens its plumage.
The Masked Gnatcatcher can be aggressive and chases intruders and predators away from its area. Some vocal and visual displays occur at the boundaries of the territory, between neighbours. We can ear vocal scolds and bill-snapping, while the tail is fanned, and raised and lowered repeatedly.
Usually, the male performs the territorial aggressive behaviours, whereas the female chases other females and juveniles.
They are often seen in pairs throughout the year, indicating probably permanent pair-bonds.
The courtship behaviour is not well known. The male may utter soft song with fluffed plumage and bill pointed upwards. Short chases of female may occur around the copulation period, at the nest-site or close to it. During the courtship period and the nest-building, the male feeds the female. They are regularly monogamous.
This species is resident in its range.
FLIGHT:
The Masked Gnatcatcher performs short flights over short distances. When the male is carrying nest materials or during the territorial chases, it makes conspicuous and direct flights.
This bird appears hesitant to cross large rivers in South America.
REPRODUCTION:
The breeding season occurs between mid-September and January in nominate race.
Both sexes build the nest, a small, deep cup made with plants fibres and spider webs to cement the materials together. In order to provide a good camouflage, the outer part is covered with lichens. The inner part is lined with fine and soft materials.
The nest is placed about 1 to 6 metres up in tree, and it is often supported by twigs. Some materials may come from previous nest.
The female lays 3-5 white or greenish-blue eggs with brown markings. Both sexes incubate during about two weeks. The chicks are fed by both parents and fledge 14-15 days after hatching. They may remain in family groups for 6-7 months.
There is one record of co-operative breeding, with one male and two females. All three adults took part in building the nest and feeding the young.
The Masked Gnatcatcher’s nest may be parasitized by the Shiny Cowbird.
DIET:
The Masked Gnatcatcher feeds on small arthropods by gleaning, hovering, sallying and probing. This is an active bird when searching for food. Its diet includes mosquitoes, butterflies, spiders and larvae.
PROTECTION / THREATS / STATUS:
The Masked Gnatcatcher is locally common throughout the range.
The nominate race and the race “berlepschi” seem to have stable populations, whereas the race “saturata” is restricted to the Bolivian montane dry forest, and could be threatened by human settlements and habitat loss for agriculture expansion.
But currently, the species is not globally threatened.
