White-headed marsh tyrant

White-headed marsh tyrant
Male in São Paulo, Brazil
Female in São Paulo, Brazil
Conservation status
Least Concern  (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Passeriformes
Family:	Tyrannidae
Genus:	Arundinicola d'Orbigny, 1840
Species:	A. leucocephala
Binomial name
Arundinicola leucocephala (Linnaeus, 1764)
Synonyms
Pipra leucocephala Linnaeus, 1764

The white-headed marsh tyrant (Arundinicola leucocephala), also known as simply the marsh tyrant, is a small passerine bird in the tyrant flycatcher family, the only species of the genus Arundinicola. It is a diurnal, a migrating, and a monogamous bird.

Description

Males

The male marsh tyrants have a white head with a small crest, a white throat, and a contrasting black body. They have dark brown irises, black legs, and the top half of their bill is also black, while their lower mandible is yellow. They usually weigh 13g and are 13cm in length.

Female in Argentina

Females

The female marsh tyrants have a white forecrown, a white throat, a greyish-brown breast, and greyish-brown flanks. Their wings and tail are also greyish-brown, although more uniform and much darker. The female usually weighs 12-12.5g and measures 13cm in length. The female and juvenile are similar in appearances.

Vocalizations

They are usually quiet, but they do have a high pitched call "sedik!". During courting, they have a lower sounding call "dew-de-lewde" that is repeated in short intervals.

Habitat and Distribution

The species is native to many south American countries such as Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Paraguay, Peru, Suriname, Trinidad and Tobago, and Venezuela.

As its name implies, these tyrants inhabit wetlands in tropical zones including marshes, bogs, swamps, fens, peatlands, rivers, streams, creeks, and moist savannas.

Behavior

Diet

Arundinicola leucocephala mainly prey on flying insects including dragonflies, grasshoppers, froghoppers and beetles.

Foraging

Tyrant flycatchers use many different types of foraging techniques such as the sally strike, sally glide, sally hover, sally pounce, leap upward, or leap downward. The type of technique used is usually linked to differences in bill, wing and tarsus structure. The sally strike (attacking in a fluid movement without gliding, hovering, or landing) is the most frequently used foraging maneuver for the marsh tyrant.

Most tyrant flycatchers hunt in living foliage or simply in the air. However, Arundinicola leucocephala captures most of its pray hunting at the water surface. The next foraging substrate most often used to catch or attempt to catch its prey is in the air followed by live leaves. They tend to perch low on small marsh plants (<2m) to then attack their prey within a 3-4m distance from their initial position. They attack prey that are mainly at the same height as them (on their perch) or below them. More rarely do they attack at a high flight angle.

Both the female and the male marsh tyrants feed the juveniles. The main differences are that the female marsh tyrant hunts further in distance and makes more visits to the young compared to the male. Regarding the nestlings, the parents try and keep the nest sanitary for them by removing arthropod remains and fecal sacs. Again the female is more active in this regard. The juveniles also participate in the cleaning, by handing the arthropod remains to the beak of its parents. It is theorized that keeping the nest clean reduces the risk of infestation by parasites and pathogens.

It is theorized that if the male were to be more active, it would increase the vulnerability of the nest to predation and may even increase the predation on the male itself by raptors nearby. This is mainly because of the more prominent colors of the male tyrant making him more noticeable in his habitat compared to the female.

Breeding

In order, the most popular breeding months are September, June, October and August followed by November and July. The spherical nest is made of grass and feathers and has a side opening near the top known as the "porch". The nest is built by both parents and it is built near or above water.

In Satarem, Brazil, many nests were found withing inches of the nest of a large species wasp. Consequently, the natives called the marsh tyrant "Mother of the Wasp".

The eggs laid are a creamy white color. The number of eggs laid in a single brood ranges from 1-3, and an individual egg ranges from 1.8-1.9 (g). These eggs usually have a length of 19.20-20.68 (mm) and a width of 11.10-14.58 (mm). The hatchlings stay about 15-17 days in the nest and then are ready to leave. The generation length of marsh tyrants is 3.6 years.

The marsh tyrant shows evidence of monogamy, since most individuals spend the majority of their time in pairs. However, once one of the individuals disappears, it is replaced by another. To attract the opposite sex, the marsh tyrant demonstrates pre-nuptial flights.

Threats

Cowbirds often parasitise the nest.

Status

This bird is not considered threatened by the IUCN. Local populations may disappear however due to declining habitat quality.

References

• de A. Gabriel, Vagner & Pizo, Marco A. (2005): Foraging behavior of tyrant flycatchers (Aves, Tyrannidae) in Brazil. Revista Brasileira de Zoologia 22(4): 1072–1077. doi:10.1590/S0101-81752005000400036 PDF fulltext
• Faria, Christiana M.A.; Rodrigues, Marcos; do Amaral, Frederico Q.; Módena, Érica & Fernandes, Alexandre M. (2006): Aves de um fragmento de Mata Atlântica no alto Rio Doce, Minas Gerais: colonização e extinção [The birds of an Atlantic Forest fragment at upper Rio Doce valley, Minas Gerais, southeastern Brazil: colonization and extinction]. Revista Brasileira de Zoologia 23(4): 1217-1230 [Portuguese with English abstract]. doi:10.1590/S0101-81752006000400032 PDF fulltext
• ffrench, Richard; O'Neill, John Patton & Eckelberry, Don R. (1991): A guide to the birds of Trinidad and Tobago (2nd edition). Comstock Publishing, Ithaca, N.Y.. ISBN 0-8014-9792-2
• Hilty, Steven L. (2003): Birds of Venezuela. Christopher Helm, London. ISBN 0-7136-6418-5

External links

• "White-headed marsh tyrant" videos on the Internet Bird Collection
• "White-headed marsh tyrant" photo gallery VIREO
• Photo-High Res; Article-w/photos
• Photo-High Res; Article geometer–"Brazil Photos"