Alagoas antwren

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Alagoas antwren

Critically Endangered  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Thamnophilidae
Genus: Myrmotherula
Species:
M. snowi
Binomial name
Myrmotherula snowi

The Alagoas antwren (Myrmotherula snowi) is a

endemic to Brazil.[2][1]

Taxonomy and systematics

The Alagoas antwren was originally described as a subspecies of the

monophyletic group with similar vocalizations and habitat requirements.[6]

The Alagoas antwren's

specific epithet honors David Snow, a British ornithologist "who was a pioneer in life history studies of Neotropical birds".[3]

Description

The Alagoas antwren is 9.5 to 10.5 cm (3.7 to 4.1 in) long and weighs about 8 to 11.5 g (0.28 to 0.41 oz). It is a small bird with a short tail. Adult males are almost entirely gray, with lighter underparts than upperparts. Their throat feathers have black bases and gray tips. Adult females are mostly rufous-brown with darker wing

coverts and paler cheeks and throat. Their iris is brown, their bill brownish gray, and their legs and feet leaden gray.[3][7]

Distribution and habitat

The Alagoas antwren was first discovered in 1979, near Murici in the eastern Brazilian state of Alagoas, and for many years was known only from that area. In the early 21st century it was discovered at several sites in Pernambuco, about 500 km (310 mi) further north. However, by about 2020 it could again be found only at Murici. It inhabits isolated fragments of semi-humid lowland evergreen forest and is known only from the narrow elevational range of 430 to 790 m (1,400 to 2,600 ft). "No doubt the distribution was much more widespread and continuous, before most forests in this region were cleared".[3][7][8]

Behavior

Movement

The Alagoas antwren is a year-round resident throughout its range.[3]

Feeding

The Alagoas antwren's diet has not been detailed but is known to include insects. It usually forages in pairs and as part of a

mixed-species feeding flocks but noted that other species typical of such flocks were seldom seen.[9]

Breeding

Prior to 2021 the Alagoas antwren's breeding biology was essentially unknown. The researchers who determined that it was a species collected a female with an egg in its oviduct in February and noted juveniles with their probable parents in May.

rhizomorphs with dried leaf fragments on the outside. They were suspended in branch forks between 1.1 and 1.6 m (3.6 and 5.2 ft) above the ground in different species of plant. The first was found in November and contained two eggs. The researchers monitored the nest for three days before it was apparently predated. During that time both parents incubated the clutch. The second nest was found in March with two damaged eggs and the third and fourth were empty in March. The researchers also mist netted juveniles between December and late April. They hypothesized that nest building began in September, egg laying in October/November, hatching in November/December, and fledging in December/January.[9]

Dickcissel male perched on a metal pole singing, with neck stretched and beak open.

Songs and calls
Listen to Alagoas antwren on xeno-canto

Vocalization

The Alagoas antwren's song is an "irregular series of very high, sharp, drawn-out, well-separated 'seeup' notes, each 'seeup' descending".[7] Its calls include "a single-syllable kleek pair-contact call" and "a three-syllable (sometimes two-syllable), slightly descending vocalization, nyiih-nyeeh-nyaah" that appears to be an alarm call.[5]

Status

The

IUCN has assessed the Alagoas antwren as Critically Endangered. It has a tiny, highly fragmented range and its estimated population of fewer than 50 mature individuals (perhaps as few as 30) is believed to be decreasing. "Forest at Murici has been reduced from 70 km2 (27 sq mi) in the 1970s to 30 km2 (12 sq mi) of highly disturbed and fragmented habitat in 1999...largely as a result of logging and conversion to pasture and sugarcane plantations. The site continues to be threatened by fires spreading from adjacent plantations, hunting, timber extraction and agriculture." "The massive clearance of Atlantic forest in Alagoas and Pernambuco has left few other sites likely to support populations of this species. Having a montane distribution that is close to the maximum altitude within its range, this species is also potentially susceptible to climate change".[1] The 2021 paper's authors urged "actions to protect its nests, recompose mixed flocks, translocate individuals to nearby habitat patches, and attempt captive breeding, [are] among efforts that should be evaluated."[9]

References

  1. ^
    doi:10.2305/IUCN.UK.2021-3.RLTS.T22724407A161705427.en
    . Retrieved 14 February 2024.
  2. Rasmussen, Pamela, eds. (January 2024). "Antbirds"
    . IOC World Bird List. v 14.1. Retrieved January 4, 2024.
  3. ^ a b c d e f g Schulenberg, T. S. and G. M. Kirwan (2020). Alagoas Antwren (Myrmotherula snowi), version 1.0. In Birds of the World (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.alaant1.01 retrieved February 14, 2024
  4. ^ a b Teixeira, D. M. & L. P. Gonzaga: Uma nova subespécie de Myrmotherula unicolor (Menétries, 1835) (Passeriformes, Formicariidae) do nordeste do Brasil. Boletim do Museu Nacional, Rio de Janeiro, Nova Série, Zoologia, No. 310: 1-16 (2)
  5. ^ a b Whitney, B.M., and J.F. Pacheco. 1997. Behavior, vocalizations, and relationships of some Myrmotherula antwrens (Thamnophilidae) in eastern Brazil, with comments on the "plain-winged" group. Pages 809-819 in J.V. Remsen, Jr. (editor), Studies in Neotropical ornithology honoring Ted Parker. Ornithological Monographs number 48. American Ornithologists' Union, Washington, D.C.
  6. ^ Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, G. Del-Rio, A. Jaramillo, D. F. Lane, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 26 November 2023. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved November 27, 2023
  7. ^
    ISBN 978-0-19-530155-7
    .
  8. ^ "Alagoas Antwren Myrmotherula snowi". BirdLife International. 2024. Retrieved February 14, 2024.
  9. ^ a b c Gonçalves, Rawelly de O.; Efe, Márcio (2021). "On the reproductive biology of the critically threatened Alagoas Antwren (Myrmotherula snowi)". The Wilson Journal of Ornithology. 133 (3): 472–476.
Wikispecies has information related to Myrmotherula snowi.
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