Justification of Red List Category
Although capable of surviving in some degraded woodlots, this species has undergone a major historical decline, such that the remaining population is believed to be very small. Therefore, the species is listed here as Vulnerable.
The total population is placed in the band 250-999 mature individuals, equating to 375-1,499 individuals in total, rounded here to 350-1,500 individuals.
There is some uncertainty regarding the current population trend, but it may be in decline due to habitat loss per Tracewski et al. (2016). Therefore, it is tentatively suspected to be in decline.
Jacamaralcyon tridactyla now occurs chiefly in small numbers at a few sites in the rio Paraíba valley in Rio de Janeiro state, and in the dry regions of east Minas Gerais, south-east Brazil. There are older records from Espírito Santo (known from only two localities and not since 1940), São Paulo (not since at least 1975) and Paraná (not reliably since 1961). Recent records from Minas Gerais have widened its known distribution (Machado et al. 1998, T. A. de Melo Júnior in litt. 1998, 1999, Silveira and Rocha Nobre 1998, Vasconcelos et al. 1999, Ribon et al. 2002, Duarte et al. 2014), and suggest that further populations may exist within this area. It was considered very common in the early and mid-19th century and must have suffered a very substantial decline in numbers. It is now local even in the core of its current diminished range.
It is now primarily restricted to small patches of dry forest, possibly associated with streams, but can persist in degraded areas where the original vegetation has been replaced (e.g. by Eucalyptus plantations [Machado and Lamas 1996, Silveira and Rocha Nobre 1998]) if a native understorey remains. It is dependent on earth banks (streamsides and roadcuttings) for nesting-cavities (Silveira and Rocha Nobre 1998). Individuals are conspicuous, perching in exposed positions in the subcanopy (8-15 m), though also lower (T. A. de Melo Júnior in litt. 1998, 1999, G. M. Kirwan in litt. 1999), from where they sally to take aerial insect prey (Silveira and Nobre 1998). Preferred food items are small cryptic Lepidoptera (G. M. Kirwan in litt. 1999) and Hymenoptera (Machado and Lamas 1996), but birds also take Diptera, Odonata, Homoptera, Hemiptera and Isoptera (Machado and Lamas 1996). Vocalisations and courtship behaviour increase at the start of the rainy season, but decrease during incubation (Vasconcelos et al. 1999).
Widespread and continuing habitat destruction have been responsible for the decline in numbers and range of this species. In addition, its specialised habitat requirements ensure that it is absent from many degraded woodlots. The species is thus vulnerable to the effects of small population size, such as local extinctions and inbreeding.
Conservation Actions Underway
It is protected under Brazilian law. It is known from Caratinga Biological Station, Rio Doce State Park, Serra do Brigadeiro State Park, Fernão Dias State Park and UFMG Ecological Station, Minas Gerais.
18 cm. Dull olivaceous, long-billed bird. Dark grey upperparts glossed green. White breast and lower belly with olivaceous-grey flanks and vent. Blackish throat, warm brown face, with bold buffy streaking on crown, whiter streaks on malar. Long tail and wings dusky. Slender, blackish bill. Voice Complex series of ascending whistles mixed with raspy notes, often delivered in groups. Also wheet call. Hints In small groups, perched motionless in subcanopy, somewhat concealed. In vicinity of exposed earth banks.
Text account compilers
Clay, R.P., Hermes, C., Capper, D., Benstead, P., Sharpe, C.J., Symes, A., Wheatley, H., Williams, R.
Kirwan, G., Melo Júnior, T.
BirdLife International (2019) Species factsheet: Jacamaralcyon tridactyla. Downloaded from http://www.birdlife.org on 19/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/10/2019.