Blue-grey gnatcatcher

Polioptila caerulea

(Photo from Internet Bird Collection)

Common name:
blue-grey gnatcatcher (en); balança-rabo-azulado (pt); gobemoucheron gris-bleu (fr); perlita grisilla (es); blaumückenfänger (de)

Taxonomy:
Order Passeriformes
Family Polioptilidae

Range:
This species breeds in the North America, as far north as southern Oregon and southern Wyoming in the west, but as far as Michigan, Maine and marginally into Canada in the east, and also throughout Mexico, in northern Guatemala, in the Bahamas and in the Turks and Caicos Islands. The more northern population migrate south to winter as far south as Cuba and the Honduras.

Size:
These birds are 10-12 cm long and have a wingspan of 16 cm. They weigh 5-7 g.

Habitat:
The blue-grey gnatcatcher is found in various scrubland and woodland habitats, particularly in temperate forests and dry tropical forests, but also moist tropical forests, mangroves, swamp forests, dry savannas, dry scrublands and second growths. They occur from sea level up to an altitude of 2.100 m.

Diet:
They feed on small arthropods, such as treehoppers, froghoppers, leaf hoppers, plant bugs, tree bugs, leaf beetles, weevils, wolf spiders, caterpillars and grasshoppers.

Breeding:
Blue-grey gnatcatchers breed in April-July. They are monogamous and both sexes cooperate in building the nest, an open cup made of plant stems, bark strips and grasses, held together by spider webs, and lined with plant down, paper, cocoons, hair, or feathers. It is attached to a branch using spider webs. The female lays 3-5 pale blue eggs with reddish-brown spots, which are incubated by both sexes for 11-15 days. the chicks are fed by both parents and fledge 10-15 days after hatching. Pairs often raise 2 broods per season.

Conservation:
IUCN status - LC (Least Concern)
This species has a very large breeding range and the global population is estimated at 160 million individuals. The populations has undergone a small increase of 1% per year over the last 5 decades.

Long-billed gnatwren

Ramphocaenus melanurus

Photo by Greg Lavaty (PBase)

Common name:
long-billed gnatwren (en); bico-assovelado (pt); microbate à long bec (fr); saltón picudo (es); schwarzschwanz-degenschnäbler (de)

Taxonomy:
Order Passeriformes
Family Polioptilidae

Range:
This species is found in Central and South America, from southern Mexico down to Bolivia and south-eastern Brazil.

Size:
These birds are 11-13 cm long and weigh 9-11 g.

Habitat:
The long-billed gnatwren is found in dry forests and woodlands, moist tropical forests, second growths and scrublands. They are present from sea level up to an altitude of 750 m.

Diet:
They eat insects and small spiders, which they find in dense undergrowths.

Breeding:
Long-billed gnatwrens breed in April-June. The nest is a deep cup made of plant fibres and placed in a small plant, sapling or vine, near the ground. The female lays 2 white eggs with reddish-brown spots, which are incubated by both parents for 16-17 days. The chicks fledge 11-12 days after hatching.

Conservation:
IUCN status - LC (Least Concern)
This species has a very large breeding range and a global population estimated at 5-50 million individuals. The population is suspected to be in decline owing to ongoing habitat destruction and fragmentation, but it is not considered threatened at present.

California gnatcatcher

Polioptila californica

Photo by Richard Bledsoe (Bird Forum)

Common name:

California gnatcatcher (en); balança-rabo-da-California (pt); gobemoucheron de Californie (fr); perlita californiana (es); Kalifornienmückenfänger (de)

Taxonomy:

Order Passeriformes

Family Polioptilidae

Range:

These birds are only found in the southernmost parts of California, in the United States, and in Baja California, Mexico.

Size:

The California gnatcatcher is 10-11 cm long and has a wingspan of 14-15 cm. They weigh 5-6 g.

Habitat:

They typically prefer open sage scrub, namely areas with California sagebrush Artemisia californica.

Diet:

Their diet consists of small insects and spiders, namely Orthoptera, Araneae, Coleoptera, Homoptera, Hymenoptera and Lepidoptera larvae.

Breeding:

California gnatcatchers build an open nest cup, placed in a scrub less than 70 cm above the ground. The female lays 3-4 eggs which are incubated by both parents for 14 days. Both parents feed the chicks until fledging, which takes place 10-15 days after hatching. Each pair may produce 3-4 clutches per year.

Conservation:

IUCN status - LC (Least Concern)

This species has a relatively restricted breeding range an a population of just 80.000 individuals. Although the population is suspected to be in decline due to ongoing habitat destruction and fragmentation, the species is not considered threatened at present.