Grass Wren
Cistothorus platensis
Tiny, bubbly, buffy-colored wren of dense grassy or shrubby habitats. Fairly common but locally distributed from central Mexico to the southernmost tip of South America; surely comprises multiple species. Occurs from open grasslands and marshes at sea level up to paramo in the high Andes. Generally secretive, but perches up when singing. Generally pale brownish with complex patterning on upperparts; compare with much plainer House Wren. Variable voice, usually including harsh chips, buzzes, and trills.
Identification
The grass wren is 10 to 10.5 cm (3.9 to 4.1 in) long. Its upperparts are buffy brown with black and buffy whitish streaks on the back. The wings and tail have dusky bands. Its underparts are mostly buffy.
Taxonomy
The grass wren was described in 1790 by the English ornithologist John Latham and given the binomial name Sylvia platensis. The type locality is Buenos Aires, Argentina. The current genus Cistothorus was introduced by the German ornithologist Jean Cabanis in 1850.<p>The grass wren and the sedge wren (Cistothorus stellaris) were formerly treated as conspecific. They were split based on the results of a molecular phylogenetic study published in 2014. This split was accepted in 2018 by the International Ornithological Committee (IOC) and BirdLife International's Handbook of the Birds of the World, in 2019 by the South American Classification Committee of the American Ornithological Society (AOS), and in 2021 by the AOS North American Classification Committee and the Clements taxonomy. As of 2018 the fourth edition of the Howard and Moore Complete Checklist of the Birds of the World had not implemented the split. Taxonomic bodies recognize 17 subspecies of the grass wren.
- Scientific name
- Cistothorus platensis
- Authority
- (Latham, 1790)
- Order
- Passeriformes
- Family
- Troglodytidae
- Genus
- Cistothorus
Range and habitat
The grass wren is found discontinuously from central Mexico south through Belize, Guatemala, Honduras, and Nicaragua into Costa Rica, in every mainland South American country except French Guiana and Suriname, and the Falkland Islands.<p>In Colombia and Ecuador, the grass wren inhabits moist grassy and sedgy parts of paramo, clearings, agricultural areas, and interandean valleys. In Brazil it inhabits cerrado, grassland, and marshes.
- Migration
- Complete migrants
Behavior
Grass wrens build two types of non‐breeding nest structures: platforms and dummy nests. Platforms are rudimentary accumulations of grasses concealed between vegetation. Dummy and breeding nests are dome‐shaped with a similar structural layer. The function of these non-breeding nests is unclear, but an experimental study suggests that building non‐breeding nests may be an attempt by males to manipulate the decision of females to breed with a mate they might otherwise reject or to start reproduction earlier than optimal for the females.<p>The grass wren's song is a "series of short,...high notes such as high rattles, sharp trills, sparrowlike 'tr-tr-tr-tr' and nasal 'zèzèzèzè'."
Conservation
- Population trend
- rising
Photos
Distribution
Bird Calls
Other Birds
Golden Monarch
Carterornis chrysomela
A beautiful, unique monarch, glowing golden with a bright fiery-orange head and a black throat with a white teardrop. Tail and wings black with large yellow wing panels. Found in most forested habitats up to 1400 meters of elevation. Song is a loud, rolling warble, “ditoweet duweet duweer teerteerteer.”
Black-and-white Shrike-flycatcher
Bias musicus
Unusual, chunky, short-tailed, crested, yellow-eyed member of the vanga family. Males are strikingly black-and-white, with a small white patch at the front of the wing. Females have a chestnut back, blackish head, and pale underparts. The wings are short and rounded, and the flight is weak. Found in the canopy of humid forest, at low and middle elevations, often along forest edge and clearings. The variable song consists of slurred whistles. Calls include rasps and clearer bulbul-like notes.
Rufous-tailed Rock-Thrush
Monticola saxatilis
Distinctive, small, short-tailed thrush-like bird. Males are strikingly beautiful with bright blue-gray head, white back patch, and chestnut underparts. Females are reddish-brown and have a scaly appearance, with a tail pattern similar to males. Breeds on rocky mountain slopes and alpine meadows, usually above 1,500 m (5,000 ft). Usually shy but may be obvious when delivering its melodic Eurasian Blackbird-like song in flight.
Start Your Bird Watching Journey
Identify a bird outdoors and keep the field guide close for your next observation.