Microcerculus philomelanightingale wren(Also: northern nightingale-wren)

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Geographic Range

The nightingale wren has a very limited range. It is found from far southeast Mexico through to Costa Rica (the northern portion of Central America). It has been seen by a few observant researchers, birdwatchers, and tourists in this area.

(Stiles & Skutch 1989)

Habitat

Microcerculus philomela lives in thick evergreen forests, which are also usually very moist, and have a large amount of cover on the forest floor. Most of the time M. philomela can be found on the forest floor, or perched on low branches and plants, and are very difficult to spot unless they are singing. Ravines and foothills in these forests are favorite environments of these birds. (Stiles & Skutch 1989)

Physical Description

Adults are usually 10-11 cm in length and weigh 18 g.

Both male and female adults have dark black markings, usually scaling on their breast and throat which have a greyish base color, but can appear almost completely black. Their dorsal side is dark brown, with black scalloping around the edges, as well as on the wings. There are a lighter spots on the wing coverts. They have a black bill and black legs.

Immature wrens have markings similar to adults, but are over-all paler in color, creating more contrast between light and dark markings.

Young wrens are even paler than immature wrens, though still similar, also with a marked contrast in color. Their scaling is mostly grey, instead of black, and their base color is more of a light cream or buff shade.

(Stiles & Skutch 1989; Howell & Webb 1995)

  • Average mass
    18 g
    0.63 oz

Reproduction

Very little is known about the nesting habits of Microcerculus philomela due to their secretive nature. Their mating season runs from May or June until September. They have been observed using previously existing nests on the floor of forests in the dirt to lay eggs and raise their young. Some biparental care has also been observed. The average clutch size is about 2-3 eggs. The incubation period usually lasts for 19-20 days during which the parents are directly involved with caring for the eggs. Once hatched, the observed time to fledging is about 16-17 days. No observations have been made of the time it takes young to reach sexual maturity. Most wrens are polygamous, so it can be hypothesized that nightingale wrens are as well, but no research supports the idea at this time.

(Stiles & Skutch 1989; Christian & Roberts 2000)

Behavior

Nightingale wrens are very elusive, which makes them difficult to study, as well as to observe and enjoy in the wild. Their markings and habit of hiding on the forest floor or in low vegetation help them to be safe, and also avoid intervention from humans. The song of these birds is largely what helps people locate them in the forest and distinguish them from other birds. Microcerculus philomela males learn only one song during their lifetime, but this song can be altered to fit different uses, such as mating and marking territory.

(Howell & Webb 1995)

Communication and Perception

Food Habits

Nightingale wrens are mostly insectivores that forage in the debris of the forest floor for insects, arachnids, and other small forest invertabrates. A peculiar behavior when searching for food is the constant motion of the tail beating on the ground as they walk. This could be used as a method of drawing food out into the open to be eaten.

(Stiles & Skutch 1989)

Economic Importance for Humans: Positive

Nightingale wrens are popular on birding resorts in Central America. Along with the many other diverse species of birds found in this region, they create an attraction for tourists and an industry for this kind of resort.

Conservation Status

Other Comments

Until recently, Microcerculus philomela was considered a subspecies of Microcerculus marginatus, which is located immediately south of the range of M. philomela. They were all lumped, along with Microcerculus luscina, under the name nightingale wren. Their geographic differences, along with distinct differences in song and physical traits have separated the groups. They are sometimes referred to as Northern and Southern nightingale wrens, respectively. This division is likely the beginning of speciation in this group of very closely related birds.

(Stiles & Skutch 1989)

Contributors

Kali Reichert (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

visual

uses sight to communicate

References

Christian, D., D. Roberts. June 2000. First description of the nest and nesting behavior of the Nightingale Wren. The Wilson Bulletin, 112: 284-287.

Howell, S., S. Webb. 1995. The Birds of Mexico and Northern Central America. Oxford, New York: Oxford University Press.

Skutch, A., F. Stiles. 1989. A Guide to the Birds of Costa Rica. Ithaca, New York: Comstock Publishing Associates/Cornell University Press.