Natural History of Ecuador's Mainland Avifauna (NHEMA).

a project of the Yanayacu Natural History Research Group
Dysithamnus occidentalis, Bicolored Antvireo

Family Thamnophilidae, Order Passeriformes
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This page was created by Harold F. Greeney in 2005. It is updated periodically and should be cited in the manner outlined on the NHEMA species list page.

Abstract:

The Bicolored Antvireo is the least known and most range-restricted of its genus. It is considered vulnerable by BirdLife International and little information exists concerning its biology within most of its range. Of the sites it is known from in Ecuador, it has been best studied in the area around the Yanayacu Biological Station. Nests are are neat cups made entirely of dark rootlets and slung between a horizonal fork of small saplings inside mature forest. Eggs are white with varing amounts of dark red-brown and lavender streaking and flecking. Clutch size, as far as known is 2, and incubation period is 19 days. Both sexes share in building, incubation, and nestling care duties. This species' preference for nesting along streams may increase its vulnerability due to the common practice by local woodcutters of using streams to remove wood from inaccessible forest tracts.

Relevant publications:

Greeney, H. F. 2002. First description of the nest for the Bicolored Antvireo (Dysithamnus occidentalis), with notes on its behavior in eastern Ecuador. Ornitologia Neotropical 13: 297-299.

Greeney, H. F. 2004. Breeding behavior of the Bicolored Antvireo (Dysithamnus occidentalis). Ornitologia Neotropical 15: 349-356.

Krabbe, N., & J. Palacio. 1999. Range extensions of Bicolored Antvireo, Dysithamnus occidentalis in Ecuador. Cotinga 11: 48.

Whitney, B. M. 1992. Observations on the systematics, behavior, and vocalizations of "Thamnomanes" occidentalis. Auk 109: 302-308.

Ecuadorian breeding dates:

DATE

LOCATION

STAGE

SOURCE of data

7 March 2003

Hacienda San Isidro/ Yanayacu Biological Station

Building

H. F. Greeney unpubl.

11 November 2002

Hacienda San Isidro/ Yanayacu Biological Station

Laying

Greeney 2004

17 November 2002

Hacienda San Isidro/ Yanayacu Biological Station

Incubation

H. F. Greeney unpubl.

2 December 2004

Hacienda San Isidro/ Yanayacu Biological Station

Nestling

H. F. Greeney unpubl.

22 December 2000

Hacienda San Isidro/ Yanayacu Biological Station

Nestling

Greeney 2002

November 1995

Hacienda San Isidro/ Yanayacu Biological Station

Dependent fledgling

M. Lysinger in Greeney 2002

15 March 2003

Hacienda San Isidro/ Yanayacu Biological Station

Older fledgling, traveling with adults

R. A. Gelis unpubl.

Photographs:

Eggs of D. occidentalis

Egg # H02-14066, 10 Nov 2002, Yanayacu Biological Station, Ecuador

Egg # H02-14074, 10 Nov 2002, Yanayacu Biological Station, Ecuador

Egg # H03-1971, 19 Mar 2003, Yanayacu Biological Station, Ecuador

Egg # H03-1988, 20 Mar 2003, Yanayacu Biological Station, Ecuador

Complete clutches of D. occidentalis in nest

Nest number H02-14248, 17 Nov 2002, Yanayacu Biological Station, Ecuador

Nest number H02-14000 10 Nov 2002, Yanayacu Biological Station, Ecuador

Nestlings of D. occidentalis

Nestling of Dysithamnus occidentalis on the day of hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis on the day of hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis on the day of hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis four days after hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis four days after hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis four days after hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis seven days after hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis seven days after hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis seven days after hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis nine days after hatching. Yanayacu Biological Station, Ecuador.

Nestling of Dysithamnus occidentalis nine days after hatching. Yanayacu Biological Station, Ecuador

Nestling of Dysithamnus occidentalis nine days after hatching. Yanayacu Biological Station, Ecuador

Additional photographs of D. occidentalis

Adult male Dysithamnus occidentalis on its nest at Yanayacu Biological Station, Ecuador. Photo by H. F. Greeney.

Nest of Dysithamnus occidentalis at Yanayacu Biological Station, Ecuador. Photo by H. F. Greeney

Seven day old Dysithamnus occidentalis nestling in nest at Yanayacu Biological Station. Photo by H. F. Greeney

Nestlings of Dysithamnus occidentalis on the day of hatching at Yanayacu Biological Station, Ecuador. Photo by H. F. Greeney.

Seven day old Dysithamnus occidentalis nestlings in nest at Yanayacu Biological Station. Photo by H. F. Greeney

Older nestlings of Dysithamnus occidentalis in nest at Yanayacu Biological Station, Ecuador. Photo by H. F. Greeney.
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