South American Leaftosser
Sclerurus obscurior
Dark, rusty-brown bird of shady forest floors in humid evergreen forest of tropical foothills and highlands; often near gullies and streambeds, where digs its nest burrow into earth banks. Feeds by tossing leaves on the forest floor. Mostly seen as it flushes, when it flies off with loud “skweek” calls. Note the long slender bill, rich rusty throat and breast, and dark rusty rump. Listen for descending series of squeaky whistles. Widespread across much of South America, to southeast Brazil.
Identification
The dusky leaftosser is 15 to 17 cm (5.9 to 6.7 in) long and weighs 20 to 30 g (0.71 to 1.1 oz). The sexes are alike. Adults of the nominate subspecies S. o. obscurior have dark reddish to chestnut brown upperparts, with their rump and uppertail coverts being more chestnut than the reddish back. Their wings are darker brown than their back and their tail is dark brown to black brown. Their face is brownish, their throat is tawny chestnut, and their chest and breast are a darker chestnut. Their bill is fairly long and straight with a dark maxilla and a bicolored mandible. Their iris is brown and their legs and feet are dusky to black. Juveniles are similar to adults but are overall duller and have light streaks on their breast and a light scaly appearance on their throat and chest.<p>Subspecies S. o. andinus is generally paler than the nominate but has a brighter rufous cast to its rump. S. o. peruvianus has entirely dark reddish brown upperparts without the chestnut rump of the nominate and andinus. S. o. macconnelli is similar to peruvianus but is somewhat olivaceous overall with a more tawny throat. S. o. bahiae has a browner back, a much brighter chestnut rump, and a darker throat than the other subspecies.
Taxonomy
The dusky leaftosser's taxonomy is unsettled. The South American Classification Committee of the American Ornithological Society (AOS), the International Ornithological Committee (IOC), and the Clements taxonomy assign it these five subspecies:<p>The North American Classification Committee of the AOS and BirdLife International's Handbook of the Birds of the World (HBW) retain an older treatment. They place these subspecies within S. mexicanus, which they respectively call the Middle American leaftosser and the tawny-throated leaftosser.<p>This article treats the dusky leaftosser as a species with five subspecies.
- Scientific name
- Sclerurus obscurior
- Authority
- Hartert, EJO, 1901
- Order
- Passeriformes
- Family
- Furnariidae
- Genus
- Sclerurus
Range and habitat
The distribution of the subspecies of the dusky leaftosser are in dispute. According to the IOC and Clements, they are found thus:<p>According to other sources detailed in Cooper et al, they are distributed thus:<p>With the exception of disjunct S. o. bahiae, the exact spatial and elevational boundaries between the subspecies are not known.<p>The dusky leaftosser generally inhabits moist tropical evergreen forest throughout its range, from lowland rainforest to humid sub-montane forest. In elevation the various subspecies range from near sea level to about 1,100 m (3,600 ft) in Brazil, 1,500 m (4,900 ft) in Ecuador, 2,100 m (6,900 ft) in Colombia, and 2,000 m (6,600 ft) in much the rest of the Andes.
Behavior
The dusky leaftosser is a year-round resident throughout its range.<p>The dusky leaftosser forages mostly on the ground, flipping aside leaves and pecking at leaf litter and rotting logs while hopping rather than walking. It typically forages alone or in pairs. Its diet is mostly invertebrates; though it has not been described in detail it is known to include spiders, beetles, ants, roaches, and their larvae.<p>The dusky leaftosser is believed to be monogamous. Its breeding season has not been defined range-wide but is known to include April and May in Colombia and April in French Guiana. It nests in a burrow in the ground with a loose cup of dry twigs in a chamber at its end. The clutch is two eggs.<p>The song of the dusky leaftosser varies somewhat in pitch and number of notes among the subspecies, but is generally "a melodious descending series of 4‒15 upslurred whistles". It may start with "a sharp spik! note" and end with a "few stuttering short notes". Its principal call is a "short sharp explosive single note Tseek!". The call is typically made at irregular intervals except when exited, when it forms a long series.
Photos
Bird Calls
Other Birds
Rufous-capped Warbler
Basileuterus rufifrons
Attractive, perky, long-tailed warbler widespread in foothills and highlands, locally in lowlands. Favors brushy and weedy areas adjacent to woodland and scrub. Usually in pairs or small groups which hop around low in brush with tails cocked. Note white eyebrow, rusty cap, and yellow bib. Birds in southeast Mexico and Belize are extensively yellow below. Listen for its buzzy trills and chips, usually given in a multi-parted series. Once considered conspecific with Chestnut-capped Warbler.
Nashville Warbler
Leiothlypis ruficapilla
Small warbler with sharply pointed bill. Look for gray head, white eyering, yellow underparts (including throat), and olive upperparts. Sometimes pumps tail. Two disjunct breeding populations are very similar in appearance. Breeds in coniferous or mixed forests, often near clearings, second-growth, or bogs. In migration and winter, tends to be found in patchy woodland or brushy areas, including field edges and thickets. Winters primarily in Mexico. Listen for its loud chipping song, broken into two parts. Compare dull immature Nashville with Virginia’s Warbler; Nashvilles always have greenish wings. Also sometimes mistaken for larger gray-headed warblers like Mourning or Connecticut, but Nashville is much smaller, shorter-tailed, and sharper-billed.
Sooty Antbird
Hafferia fortis
Large, chunky antbird. Male is uniformly sooty black with pale blue skin around the eye. Female is warm dark brown above and gray below, and also has blue skin around the eye. Occurs in pairs in the understory of mature lowland forest in the Amazon basin, east of the Andes. Can be seen in the vicinity of army ant swarms. Look for the tail being pumped down and raised slowly up.
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