Wednesday 8 April 2015

Vermiculated screech-owl

Megascops vermiculatus

Photo by Arlene Koziol (Flickr)

Common name:
vermiculated screech-owl (en); corujinha- (pt); petit-duc vermiculé (fr); autillo vermiculado (es); kritzel-kreischeule (de)

Taxonomy:
Order Strigiformes
Family Strigidae

Range:
This species is found from northern Costa Rica to Colombia, and along the Andes south to northern Bolivia. There are also separate populations in north-western Colombia and northern Venezuela, and in southern Venezuela, Guyana, Suriname and extreme northern Brazil.

Size:
These birds are 20-23 cm long and weigh 90-130 g.

Habitat:
The vermiculated screech-owl is mostly found in humid tropical forests, also using dry tropical forests. They are mainly found in lowland areas, but can occur up to an altitude of 1.800 m.

Diet:
They feed mainly on large insects, but possibly also some small vertebrates.

Breeding:
Vermiculated screech-owls breed in March-July. They nest in natural tree cavities, or sometimes in old nest holes of other birds such as trogons. The female lays 2-3 eggs which she mainly incubates alone for 26-37 days. There is no information regarding the fledging period, but when food is scarce the larger chicks may eat their smaller siblings.

Conservation:
IUCN status - LC (Least Concern)
This species has a large breeding range. There is very little information about its abundance, but its possibly not rare, at least in some areas. The population is suspected to be in decline owing to ongoing habitat destruction and fragmentation.

Tuesday 7 April 2015

Black-throated blue warbler

Dendroica caerulescens

Photo by Paul Jones (Flickr)

Common name:
black-throated blue warbler (en); felosa-azul-de-garganta-preta (pt); paruline bleue (fr); reinita azulada (es); blaurücken-waldsänger (de)

Taxonomy:
Order Passeriformes
Family Parulidae

Range:
This species breeds in south-eastern Canada, from southern Ontario to Nova Scotia, and southwards into the eastern United States as far south as Tennessee and northern Georgia. they migrate south to winter in the Caribbean, from southern Florida south to Panama and Barbados.

Size:
These birds are 13 cm long and weigh about 8,5-12 g.

Habitat:
The black-throated blue warbler breeds in undisturbed deciduous and mixed-deciduous forests, particularly maple, birch, beech, hemlock, spruce and fir, favouring areas with dense understory. Outside the breeding season they also use moist tropical forests, tropical scrublands, plantation, rural gardens and urban areas.

Diet:
During the breeding season they are mainly insectivorous, taking beetles, caterpillars, butterflies, flies, bugs and spiders. During the rest of the year they complement this diet with fruits, berries and seeds.

Breeding:
These birds are generally monogamous, although extra-pair copulations are common in both sexes. The nest is built by the female, consisting of a cup made of bark, dried grasses and twigs, and lined with fur, mosses or rootlets. the nest is usually place less than 1,5 m above the ground in dense foliage. There the female lays 2-5 white eggs with dark speckles, which she incubates alone for 12-13 days. The chicks are fed by both parents and fledge 8-10 days after hatching.

Conservation:
IUCN status - LC (Least Concern)
This species has a large breeding range and is described as common. Overall the population has undergone a small increase in the last 4 decades, although some local decreases took place at the edges of the range and have been attributed to habitat loss and fragmentation.