Plumages, Molts, and Structure

Natal Down

Information needed.

Juvenile Plumage

Varies from cinnamon-brown with gray touches to brown plumage with dark spots. Many feathers on the body have darker gray or blackish bases with broad cinnamon-brown to buffy-brown tips, creating an intricate and fine barring pattern on the head, breast, and flanks; on the mantle, the dark feather centers and paler tips create a scalloped pattern. The upperwing coverts similarly darker gray to gray-brown with paler buffy tips, forming an indistinct wing bar. Its plumage becomes darker as it molts.

Based on recent studies, the Juvenile plumage of individuals from Navarino Island have a slightly different phenotype, including a light gray crown, head, and throat, a mottled grayish-brown chest, and a cinnamon-coffee colored body, different from the barred plumage with dark brown of the juveniles from other localities (7 Correa, A., D. Rossi, D. Asperó, and O. N. G. Omora (2012). Phenotype differences in the juvenile plumage of Churrin (Scytalopus magellanicus) of Isla Navarino, Chile. 7th International Symposium on Health Informatic and Bioinformatics. HIBIT 2012. Poster 19. 10.13140/2.1.3251.6488. Close ). This needs further studies to gain more certainty about the alleged differences.

Formative Plumage

Not described. Based on images from Macaulay Library, appears rather variable, but usually includes retained Juvenile remiges, and retention of at least some Juvenile wing coverts, as in Dusky Tapaculo (Scytalopus fuscus) (see Molts).

Definitive Basic Plumage

The adult has primarily dark gray plumage, including the rectrices and remiges, which are sometimes lighter than the plumage on the rest of the body. The flanks, abdomen, and tarsi can maintain a barred-browned plumage, similar to the juvenile, but is darker. Some individuals from southern populations have a silvery-white forecrown, which can vary from a single whitish feather to a completely white forehead (2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ) Individuals from northern populations of the high Andes are larger and darker, with less barred plumage, and without the white crown of the southern populations (8 Jaramillo, A. (2003). A Field Guide to the Birds of Chile Including the Antarctic Peninsula, the Falkland Islands and South Georgia. Christopher Helm, London, UK. Close ), some authors claim there is a sexual dichromatism, being the females in high Andes brownish (9 Martínez, D., and G. González (2017). Las aves de Chile. Guía de Campo y Breve Historia Natural. Ediciones del Naturalista, Santiago, Chile. Close ).

Nothing is described, but it is likely similar to Dusky Tapaculo, its sister species. Magellanic Tapaculo likely has a Complex Basic Molt strategy, although there is some evidence that Dusky Tapaculo may also have a Prealternate Molt (see below), suggesting they might instead have a Complex Alternate Molt strategy; more study is needed.

The following information pertains to Dusky Tapaculo studied in Fray Jorge National Park, and is based on Pyle et al. (10 Pyle, P., A. Engilis, Jr., and D. A. Kelt (2015) Manual for ageing and sexing the landbirds of Bosque Fray Jorge National Park and north-central Chile, with notes on range and breeding seasonality. Special Publication, Occasional Papers of the Louisiana State University Museum of Natural Science. Close ) unless otherwise noted.

Prejuvenile Molt

Occurs from November–December.

Preformative Molt

The Preformative Molt is partial, probably occurring between November and March; the limits appear to be subtle. Few (if any) wing coverts or tertials are replaced, although one specimen appeared to maintain the outer three greater coverts. Most remiges appear to be retained from Juvenile plumage.

Definitive Prebasic Molt

Occurs between December and February, after breeding. One male seems to have replaced tertials on both wings, suggesting there may be a Prealternative Molt; more study is needed (10 Pyle, P., A. Engilis, Jr., and D. A. Kelt (2015) Manual for ageing and sexing the landbirds of Bosque Fray Jorge National Park and north-central Chile, with notes on range and breeding seasonality. Special Publication, Occasional Papers of the Louisiana State University Museum of Natural Science. Close ).

Bill

Blackish. The bill in juveniles starts off pale pinkish or pinkish gray, but slowly darkens to blackish. In juveniles from Navarino Island, the bill is yellowish-orange.

Iris

Brown to dark brown.

Tarsi and Toes

Yellowish or pinkish, to blackish. In juveniles from Navarino Island, the tarsi are yellowish-orange.

Linear Measurements

All the measurements from Correa and Mpodozis (11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ) are from museum specimens.

Total Length

100–120 mm (2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close , 12 Goodall, J. D., A. W. Johnson, and R. A. Philipps (1946) Las aves de Chile. Volume 1. Platt Establecimientos Gráficos, Buenos Aires. Close , 8 Jaramillo, A. (2003). A Field Guide to the Birds of Chile Including the Antarctic Peninsula, the Falkland Islands and South Georgia. Christopher Helm, London, UK. Close , 5 Couve, E., C. F. Vidal, and J. Ruiz (2016). Aves de Chile - Sus islas oceánicas y Península Antártica. FS- Editorial Fantástico Sur, Punta Arenas, Chile. Close , 13 Ridgely, R. S., and G. Tudor (1989). The Birds of South America. Volume 2: The Suboscine Passerines. University of Texas Press, Austin, TX, USA. Close , 14 Pearman, M., and J. I. Areta (2021). Birds of Argentina and the South-west Atlantic. Princeton University Press, NJ, USA. Close ); mean 112 ± 1.5 mm (n = 38; 15 Riveros, G., and N. Villegas (1994). Análisis taxonómico de las subespecies chilenas de Scytalopus magellanicus (Familia: Rhinocryptidae, Aves) a través de sus cantos. Anales del Museo de Historia Natural de Valparaíso 22:91-101. Close ).

Wing Length

Entire Distribution. Mean 49.1 ± 0.44 mm (16 Johnson, A. W. (1967). The Birds of Chile and Adjacent Regions of Argentina, Bolivia and Peru. Volume 2. Platt Establecimientos Gráficos, Buenos Aires, Argentina. Close ); mean 48.5 ± 1.8 mm (n = 38; 15 Riveros, G., and N. Villegas (1994). Análisis taxonómico de las subespecies chilenas de Scytalopus magellanicus (Familia: Rhinocryptidae, Aves) a través de sus cantos. Anales del Museo de Historia Natural de Valparaíso 22:91-101. Close ); 47–52 mm; n = 11 (12 Goodall, J. D., A. W. Johnson, and R. A. Philipps (1946) Las aves de Chile. Volume 1. Platt Establecimientos Gráficos, Buenos Aires. Close ).

Southern Chile and Argentina. Male 49.7 ± 1.42 mm (n = 10); female 48.1 ± 1.02 mm (n = 6; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Magallanes and Tierra del Fuego. Male: 52.7 ± 1.15 mm (n = 3; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

There is a record of 58 mm of an individual in Horcones Valley, Mendoza, Argentina, formerly identified as a Dusky Tapaculo (Scytalopus fuscus), but considering distribution, it is highly probable that it is in fact a Magellanic Tapaculo (2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Tail Length

Entire Distribution. Mean 31 ± 0.74 mm (16 Johnson, A. W. (1967). The Birds of Chile and Adjacent Regions of Argentina, Bolivia and Peru. Volume 2. Platt Establecimientos Gráficos, Buenos Aires, Argentina. Close ); mean 39.6 ± 1.2 mm, n = 38 (15 Riveros, G., and N. Villegas (1994). Análisis taxonómico de las subespecies chilenas de Scytalopus magellanicus (Familia: Rhinocryptidae, Aves) a través de sus cantos. Anales del Museo de Historia Natural de Valparaíso 22:91-101. Close ); 28–36 mm, n = 11 (12 Goodall, J. D., A. W. Johnson, and R. A. Philipps (1946) Las aves de Chile. Volume 1. Platt Establecimientos Gráficos, Buenos Aires. Close ).

Southern Chile and Argentina. Male 31.3 ± 0.82 mm (n = 10); female 29.3 ± 1.03 mm (n = 6; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Magallanes and Tierra del Fuego. Male: 34.3 ± 2.08 mm (n = 3; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Bill Length

Entire Distribution. Mean 10.5 ± 0.22 mm (16 Johnson, A. W. (1967). The Birds of Chile and Adjacent Regions of Argentina, Bolivia and Peru. Volume 2. Platt Establecimientos Gráficos, Buenos Aires, Argentina. Close ); mean 11 ± 0.13 mm (n = 2; 11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ); mean 10.6 ± 0.2 mm (n = 38; 15 Riveros, G., and N. Villegas (1994). Análisis taxonómico de las subespecies chilenas de Scytalopus magellanicus (Familia: Rhinocryptidae, Aves) a través de sus cantos. Anales del Museo de Historia Natural de Valparaíso 22:91-101. Close ); 9.5–12 mm (n = 11; 12 Goodall, J. D., A. W. Johnson, and R. A. Philipps (1946) Las aves de Chile. Volume 1. Platt Establecimientos Gráficos, Buenos Aires. Close ).

Southern Chile and Argentina. Male 10.9 ± 0.5 mm (n = 8); female 10.1 ± 0.55 mm (n = 5; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Magallanes and Tierra del Fuego. Male 10.8 ± 0.3 mm (n = 3; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

There is a record of a 12.5 mm individual in Horcones Valley, Mendoza, Argentina, formerly identified as Dusky Tapaculo, but considering distribution, it is highly probable that it is in fact aMagellanic Tapaculo (2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Bill Width

Mean: 3.6 ± 0.14 mm (n = 2; 11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ); 3.3 ± 0.2 mm (n = 38; 15 Riveros, G., and N. Villegas (1994). Análisis taxonómico de las subespecies chilenas de Scytalopus magellanicus (Familia: Rhinocryptidae, Aves) a través de sus cantos. Anales del Museo de Historia Natural de Valparaíso 22:91-101. Close ).

Head Length

Mean: 2.12 ± 0.021 cm (n = 2; 11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ).

Head Width

Mean: 1.73 ± 0.26 mm (n = 2; 11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ).

Thigh Length

Mean: 1.45 ± 0.11 cm (n = 2; 11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ).

Tarsus Length

Entire Distribution. Mean: 21.1 ± 0.2 mm (n = 2; 11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ); 18.9 ± 0.7 mm (n = 38; 15 Riveros, G., and N. Villegas (1994). Análisis taxonómico de las subespecies chilenas de Scytalopus magellanicus (Familia: Rhinocryptidae, Aves) a través de sus cantos. Anales del Museo de Historia Natural de Valparaíso 22:91-101. Close ).

Southern Chile and Argentina. Male 18.5 ± 0.89 mm (n = 8); female 17.6 ± 0.66 mm (n = 6; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Magallanes and Tierra del Fuego. Male 18.5 ± 0.7 mm (n = 2; 2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

There is a record of 19 mm of an individual in Horcones Valley, Mendoza, Argentina, formerly identified as Dusky Tapaculo, but considering distribution it is highly probable that it is in fact a Magellanic Tapaculo (2 Hellmayr, C. E. (1932). The birds of Chile. Publications of the Field Museum Natural History, Zoological Series 19:1–472. Close ).

Central front tarsi

Mean 19.3 ± 0.13 mm, n = 2 (11 Correa, A., and J. Mpodozis (2008). Speciation of chilean Rhinocryptidae (Avian) based on their behaviour. Nature Precedings (2008) Close ).

Mass

All reported values are from Chiloé Island; range reported as 11–12 g (17 De Santo, T. L., M. F. Willson, K. E. Sieving, and J. J. Armesto (2002) Nesting biology of tapaculos (Rhinocryptidae) in fragmented south-temperate rainforests of Chile. Condor 104: 482-495. Close ). There is a record from Chiloé of an individual that weighed 9.5 g (18 Rozzi, R., J. J. Armesto, A. Correa, J. C. Torres-Mura, and M. Sallaberry (1996). Avifauna of primary temperate forests of uninhabited islands of Chiloe Archipelago, Chile. Revista Chilena de Historia Natural 69(1):125-139. Close ), but its other morphological measurements were also below the mean for the species (total length 98 mm, wing length 45 mm, tarsi length 23 mm, bill length 8 mm, bill width 3.1 mm, and bill height 3.1 mm).