Magnolia warbler

The magnolia warbler (Setophaga magnolia) is a member of the wood warbler family Parulidae.

Etymology

The genus name Setophaga is from Ancient Greek ses, "moth", and ', "eating", and the specific magnolia refers to the type locality. American ornithologist Alexander Wilson found this species in magnolias near Fort Adams, Mississippi.

Description

thumb|left|First-year male magnolia warbler

This species is a moderately small New World warbler. It measures in length and spans across the wings. Body mass in adult birds can range from , though weights have reportedly ranged up to prior to migration. Among standard measurements, the wing chord is , the tail is , the bill is and the tarsus is . The magnolia warbler can be distinguished by its coloration. The breeding males often have white, gray, and black backs with yellow on the sides; yellow and black-striped stomachs; white, gray, and black foreheads and beaks; distinct black tails with white stripes on the underside; and defined white patches on their wings, called wing bars. Breeding females usually have the same type of coloration as the males, except that their colors are much duller. Immature warblers also resemble the same dull coloration of the females. The warbler breeds in dense forests, to reach its wintering grounds in southern Mexico, Central America, and the Caribbean. During migration season, the magnolia warbler can be found in various types of woodlands.

Life cycle

The magnolia warbler undergoes multiple molts during its lifetime. The first molts begin while the young offspring are still living in the nest, while the rest take place on or near their breeding grounds.

Hybridization

Rare hybrids between the magnolia warbler and the congeneric American redstart (Setophaga ruticilla) have been documented on two occasions, in Ohio, USA, and Quebec, Canada. In both cases, the hybrid's mother was a magnolia warbler and the father was a redstart.

Behavior

Diet and feeding

This warbler usually eats any type of arthropod, but their main delicacies are caterpillars. The warbler also feeds on different types of beetles, butterflies, spiders, and fruit during their breeding season, while they increase their intake of both fruit and nectar during the winter. These songs have two distinct purposes – one used to attract mates, and the other to defend territory. Females, while they do sing, have not been observed to have separate songs for different situations. Both males and females have call notes that they use for various alerts: the females have short call notes to signal when a human observer is watching them, and the males have short call notes to signal when any sort of threatening predators are close to their offspring.

Reproduction

Male magnolia warblers go to their breeding grounds about two weeks before the females arrive. After the females come to the breeding grounds, both the males and females cooperate to build the nest for a week. Because of the difficulty of locating their nests among the forest's dense undergrowth, it is hard to know whether the warblers re-use their original nests each breeding season, or whether they abandon them for new ones. The nests are built in their tree of choice – different types of fir trees, such as Abies balsamea (balsam fir) and Picea glauca (spruce fir). The nest is made up of grass, twigs, and horsehair fungus, and they are relatively small, shallow, circular-shaped nests, barely exceeding 10 cm on all sides. Because the males are technically as equally responsible for feeding the newborns as the females are, this means that the males are monogamous because they expend a large amount of energy looking for food for their young. In order to keep the nest clean, females eat the fecal sacs of their newborns; as the chicks grow older, both parents simply remove the sacs from the nest. The baby warblers are ready to fly out of the nest by the time they are ten days old.

Conservation

The magnolia warbler is assessed on the IUCN Red List as least concern for conservation because it is fairly widespread and common within its habitat and not at risk of extinction. Research has shown that a good percentage of warblers die from flying into television towers in their migratory path. Also, parts of their habitat have been degraded as coniferous forests are cleared which causes the number of warblers living in a habitat to decrease, but they certainly are not greatly affected by the deforestation. While the deforestation does decrease the warbler population in the specific area that it occurs in, the species is not significantly impacted overall due to the general abundance of the species throughout the region.

In art

thumb|[[John James Audubon's Black & Yellow Warbler (magnolia warbler), Plate 123 from The Birds of America]]

John James Audubon illustrated the magnolia warbler in The Birds of America, Second Edition (published, London 1827–38) as Plate 123 under the title, "Black & Yellow Warbler – Sylvia maculosa" where a pair of birds (male and female) are shown searching flowering raspberry for insects. The image was engraved and colored by Robert Havell's London workshops. The original watercolor by Audubon was purchased by The New York Historical.

References

External links

Magnolia warbler species account – Cornell Lab of Ornithology
Magnolia warbler - Dendroica magnolia - USGS Patuxent Bird Identification InfoCenter

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