Unicolored Blackbird

agelaius cyanopus

Icteridae,Icterinae · Troupials

Disc 2 · 2001 listed
Disc 3 · 2006 listed
Disc 1 · 2011 listed

The account

Description

19 cm. Male glossy black.

Female mantle dark brown, streaked blackish. Wings black, the primaries edged dark rufous. Underparts dark olive brown. Throat greenish yellow, slightly streaked black. Flanks streaked. Willis & Oniki (¹¹⁹) show a female that resembles the male, but has an olive yellowish belly with a black chest and throat.

Male Disc 3 · 2006
Female Disc 3 · 2006

Each plate is labelled with the disc's own caption.

Where it was recorded

The discs' own checklists select Unicolored Blackbird at 4 localities.

Historical checklist localities on the disc's own area map — the red dots the original program drew, placed by its recovered projection. Not a range map: it shows the places whose checklists record the bird, nothing more.

How the map was made

The original program computed each red dot at display time from the locality's coordinates, using its map library and one of five base maps drawn for the screen widths of the day. That library's projection — an oblique rotation of the sphere about the map's own centre, 23.7°S 47.4°W — was read from the program and checked against the graticule the same program drew into the base maps: it reproduces every grid intersection to within about a pixel. The dots here use that projection on the 1280-pixel base map, with the coordinates the discs record. Nothing was placed by hand, no modern map data was used, and a place whose coordinate is incomplete, out of range or beyond the map's edge is listed rather than guessed.

The discs carried location maps only; none shows a distribution or range.

Voice

Call 'chek'. Song a sequence of upward tew tew tew and a gurgling rattle 'trrrrrrrrr'. Ruffles feathers and spreads tail in display.

Behavior

Forages in cattails and other aquatic vegetation, much more skulking than Agelaius ruficapillus and sometimes difficult to see. Found in small groups and pairs.

Breeding

Breeds in loose colonies, November (¹⁶⁷).

Habitat and status

Locally common in wetlands with standing water, reed beds (with Juncus, Typha, Scirpus species), marshes. Some times forages in agricultural areas (62}.

Distribution

Wetlands close to coast from Rio de Janeiro northward (¹⁶⁷), e.g at Lagoa Feia(⁴⁰). Widely distributed inland. To 500 meters

Taxonomy notes

The female of the race atroolivaceus of coastal Southeast Brazil (depicted) is much darker underneath than females of other races.

Decoded from the disc's own bytes. Each part is shown under the heading the disc files it under, and the wording, spelling and punctuation are the author's.

Vocalizations

Calls of pair after playback. Juiz de Fora, MG. 11/2/00. Sunny, 25°C. Cattail swamp in open country. With Chiroxiphia caudata, Vireo olivaceus.
Calls, Beni, Bolivia, LNS 100669, recorded by B. Hennessy.

Recording files on the disc

13304.mp3 Calls of pair after playback. Juiz de Fora, MG. 11/2/00. Sunny, 25°C. Cattail swamp in open country. With Chiroxiphia caudata, Vireo olivaceus.
6994.mp3 Calls, Beni, Bolivia, LNS 100669, recorded by B. Hennessy.

Across the three discs

The work was published on three discs — Disc 2 in 2001, Disc 3 in 2006 and Disc 1 in 2011. Where they differ, that is a difference between historical releases, and it is never merged away. The 2011 disc is not treated as correcting the earlier ones.

Which discs list this bird

Disc 2 · 2001 — in this disc's bird list
Disc 3 · 2006 — in this disc's bird list
Disc 1 · 2011 — in this disc's bird list

How that was established

Disc 2 · 2001: aux_nonzero;local_checklist_byte45_flag_1
Disc 3 · 2006: aux_nonzero;local_checklist_byte45_flag_1
Disc 1 · 2011: aux_nonzero;local_checklist_byte45_flag_1

The disc's own record fields that place the bird on its list: a non-empty entry in the species table, and the byte that marks it as selected on a local checklist.

The account in the Disc 1 · 2011 revision

The 2011 Disc 1 revision carries this account text unchanged from the Disc 3 release.

The work's own taxonomy

The discs carried three parallel name schemes. All three are shown as recovered; none is a modern taxonomy and none has been updated.

Scheme	Scientific name	English name	Family
WORLD	agelaius cyanopus	Unicolored Blackbird	Icteridae,Icterinae
CLEMENTS	agelaius cyanopus	Unicolored Blackbird	Icteridae,Icterinae
AOU_HM	chrysomus cyanopus	Unicolored Blackbird	Icteridae,Icterinae

Source details

Identifier on this site: seb_species_0458
Account identifier: seb_account_0458
Account number on the disc: 458
Source edition: CD03 / 2006 package
Original taxonomy scheme: WORLD
Structure status: heuristic; decoded_account_text and segment JSON remain authoritative