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 phagos, "eating", and the specific magnolia refers to the type locality. American ornithologist Alexander Wilson found this species in magnolias near Fort Adams, Mississippi.

Description
This species is a moderately small New World warbler. It measures 11 to 13 cm in length and spans 16 to 20 cm across the wings. Body mass in adult birds can range from 6.6 to 12.6 g, though weights have reportedly ranged up to 15 g prior to migration. Among standard measurements, the wing chord is 5.4 to 6.4 cm, the tail is 4.6 to 5.2 cm, the bill is 0.8 to 1 cm and the tarsus is 1.7 to 1.85 cm. 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 yellow and black-striped stomachs help one to distinguish the males from other similar birds, like the prairie warbler and Kirtland's warbler (which, however, have a breeding range to the south and east of the magnolia warbler's).

Distribution
The magnolia warbler is found in the northern parts of some Midwestern states and the very northeastern parts of the US, with states such as Minnesota and Wisconsin comprising its southernmost boundaries. However, it is mostly found across the northern parts of Canada, such as in Saskatchewan, Manitoba, Ontario, and Quebec. During the winter, the warbler migrates through the eastern half of the United States to southern Mexico and Central America. The warbler breeds in dense forests, where it will most likely be found among the branches of young, densely packed, coniferous trees. The magnolia warbler migrates to the warmer south in the winter, wintering in southeastern Mexico, Panama, and parts of the Caribbean. In migration it passes through the eastern part of the United States as far west as Oklahoma and Kansas. 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. The warblers molt, breed, care for their offspring, and then migrate. Chicks hatch after a two-week incubation period, and can fledge from the nest after close to another two weeks when their feathers are more developed. After about a month, the chicks can leave the nest to begin living (and later breeding) on their own since they are solitary birds. Magnolia warblers typically live up to seven years.

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.

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 birds also tend to eat parts of the branches of mid-height coniferous trees, such as spruce firs, in their usual breeding habitat.

Songs


Researchers have observed two different types of songs in male magnolia warblers. Their songs have been referred to as the First Category song and the Second Category song. 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. The nests are usually found close to the ground, commonly in the lowest three meters of the firs.

Female magnolia warblers usually lay three to five eggs during each breeding season. The female will not incubate her eggs until all of them are laid. The female sits on the eggs for about two weeks before the eggs hatch. The female is also the one that warms the newborn chicks by brooding, or sitting, on the nest; she is also the one who feeds the newborn chicks most frequently, though the males also engage in feeding the offspring at times. 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
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 History Society.

Books

 * Hall, G. A. 1994. Magnolia Warbler (Dendroica magnolia). In The Birds of North America, No. 136 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union.

Thesis

 * Elam K. M.S. (2004). The magnolia warbler Dendroica magnolia on Unaka Mountain, Unicoi County, Tennessee: Possible breeding and habitat analysis. East Tennessee State University, United States, Tennessee.
 * Smith AL. M.Sc. (1997). Habitat suitability of successional forests for the bird community of Campeche, Mexico. Queen's University at Kingston (Canada), Canada.
 * Woodrey MS. Ph.D. (1995). Stopover behavior and age-specific ecology of neotropical passerine migrant landbirds during autumn along the northern coast of the Gulf of Mexico. The University of Southern Mississippi, United States, Mississippi.

Articles
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 * Barnard WH. (1996). Juvenile Gray Jay preys upon Magnolia Warbler. Journal of Field Ornithology. vol 67, no 2. p. 252-253.
 * Barrowclough GF & Corbin KW. (1978). Genetic Variation and Differentiation in the Parulidae. Auk. vol 95, no 4. p. 691-702.
 * Boal CW, Sibley FC, Estabrook TS & Lazell J. (2006). Insular and migrant species, longevity records, and new species records on Guana Island, British Virgin Islands. Wilson Journal of Ornithology. vol 118, no 2. p. 218-224.
 * Caroline G, Marcel D, Jean-Pierre LS & Jean H. (2004). Are temperate mixedwood forests perceived by birds as a distinct forest type?. Canadian Journal of Forest Research. vol 34, no 9. p. 1895.
 * Collins SL, James FC & Risser PG. (1982). Habitat Relationships of Wood Warblers Parulidae in Northern Central Minnesota USA. Oikos. vol 39, no 1. p. 50-58.
 * Cumming EE & Diamond AW. (2002). Songbird community composition versus forest rotation age in Saskatchewan boreal mixedwood forest. Canadian Field Naturalist. vol 116, no 1. p. 69-75.
 * Dralle B. (1992). A winter record for magnolia warbler at Carters Lake. Oriole. vol 57, no 1-4.
 * Dunn EH. (2000). Temporal and spatial patterns in daily mass gain of Magnolia Warblers during migratory stopover. Auk. vol 117, no 1. p. 12-21.
 * Enright SD. (1995). Magnolia Warbler in Scilly: New to Britain and Ireland. British Birds. vol 88, no 2. p. 107-108.
 * Goodpasture KA. (1979). A Transient Magnolia Warbler Dendroica-Magnolia Returns. Bird Banding. vol 50, no 3.
 * Greenberg R & Ortiz JS. (1994). Interspecific defense of pasture trees by wintering yellow warblers. Auk. vol 111, no 3. p. 672-682.
 * Hall GA. (1981). Fall Migration Patterns of Wood Warblers in the Southern Appalachians USA. Journal of Field Ornithology. vol 52, no 1. p. 43-49.
 * Hall GA. (1994). Magnolia warbler. Birds of North America. vol 0, no 136. p. 1-15.
 * Hobson KA & Bayne E. (2000). Breeding bird communities in boreal forest of western Canada: Consequences of "unmixing" the mixedwoods. Condor. vol 102, no 4. p. 759-769.
 * Hobson KA & Bayne E. (2000). Effects of forest fragmentation by agriculture on avian communities in the southern boreal mixedwoods of western Canada. Wilson Bulletin. vol 112, no 3. p. 373-387.
 * Hobson KA & Bayne E. (2000). The effects of stand age on avian communities in aspen-dominated forests of central Saskatchewan, Canada. Forest Ecology & Management. vol 136, no 1-3. p. 121-134.
 * Holmes SB & Pitt DG. (2007). Response of bird communities to selection harvesting in a northern tolerant hardwood forest. Forest Ecology & Management. vol 238, no 1-3. p. 280-292.
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 * Machtans CS & Latour PB. (2003). Boreal forest songbird communities of the Liard Valley, Northwest Territories, Canada. Condor. vol 105, no 1. p. 27-44.
 * Millikin RL & Smith JNM. (1990). Sublethal Effects of Fenitrothion on Forest Passerines. Journal of Applied Ecology. vol 27, no 3. p. 983-1000.
 * Mills ED & Rogers DTJ. (1992). Ratios of Neotropical Migrant and Neotropical Resident Birds in Winter in a Citrus Plantation in Central Belize. Journal of Field Ornithology. vol 63, no 2. p. 109-116.
 * Mitchell JM. (1999). Habitat relationships of five northern bird species breeding in hemlock ravines in Ohio, USA. Natural Areas Journal. vol 19, no 1. p. 3-11.
 * Morris SR. (1996). Mass loss and probability of stopover by migrant warblers during spring and fall migration. Journal of Field Ornithology. vol 67, no 3. p. 456-462.
 * Morris SR, Richmond ME & Holmes DW. (1994). Patterns of stopover by warblers during spring and fall migration on Appledore Island, Maine. Wilson Bulletin. vol 106, no 4. p. 703-718.
 * Morse DH. (1977). The Occupation of Small Islands by Passerine Birds. Condor. vol 79, no 4. p. 399-412.
 * Morse DH. (1989). Song Patterns of Warblers at Dawn and Dusk. Wilson Bulletin. vol 101, no 1. p. 26-35.
 * Mulvihill RS. (1992). Magnolia warbler Dendroica magnolia. Brauning, D. vol W, p. Atlas of breeding birds in Pennsylvania.
 * Nice, M. M. 1926. A Study of a Nesting of Magnolia Warblers (Dendroica magnolia). The Wilson Bulletin (Published by Wilson Ornithological Society) 38(4): 185–199.
 * Patten MA & Burger JC. (1998). Spruce budworm outbreaks and the incidence of vagrancy in eastern North American wood-warblers. Canadian Journal of Zoology. vol 76, no 3. p. 433-439.
 * Pranty B, Hince T & Berney M. (2005). First verifiable records of Blue-winged Warbler and Magnolia Warbler wintering in Florida. Florida Field Naturalist. vol 33, no 1. p. 17-19.
 * Quintana-Barrios L, Ruiz-Campos G, Unitt P & Erickson RA. (2006). Update on the birds of Isla Guadalupe, Baja California. Western Birds. vol 37, no 1. p. 23-36.
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 * Rodewald PG & Brittingham MC. (2002). Habitat use and behavior of mixed species landbird flocks during fall migration. Wilson Bulletin. vol 114, no 1. p. 87-98.
 * Rodewald PG & Matthews SN. (2005). Landbird use of riparian and upland forest stopover habitats in an urban landscape. Condor. vol 107, no 2. p. 259-268.
 * Sabo SR. (1980). Niche and Habitat Relations in Subalpine Bird Communities of the White Mountains of New-Hampshire USA. Ecological Monographs. vol 50, no 2. p. 241-260.
 * Sabo SR & Whittaker RH. (1979). Bird Niches in a Subalpine Forest an Indirect Ordination. Proceedings of the National Academy of Sciences of the United States of America. vol 76, no 3. p. 1338-1342.
 * Skinner C. (2003). A breeding bird survey of the natural areas at Holden Arboretum. Ohio Journal of Science. vol 103, no 4. p. 98-110.
 * Stewart PA. (1986). Fall Migration of Twelve Species of Wood Warblers through Coastal Virginia USA. North American Bird Bander. vol 11, no 3. p. 83-88.
 * Sutherland D. (1986). Magnolia Warbler Dendroica-Magnolia Breeding in the Regional Municipality of Halton Ontario Canada. Ontario Birds. vol 4, no 2. p. 69-71.
 * Tingley SI. (1978). WHEATEARS AND A MAGNOLIA WARBLER IN SOUTHERN DAVIS STRAIT. Canadian Field-Naturalist. vol 92, no 2. p. 199-199.
 * Vera CJ & Servello FA. (1994). Effects of paper mill sludge in spruce-fir forests on wildlife in Maine. Journal of Wildlife Management. vol 58, no 4. p. 719-727.
 * Woodrey MS & Chandler CR. (1997). Age-related timing of migration: Geographic and interspecific patterns. Wilson Bulletin. vol 109, no 1. p. 52-67.
 * Woodrey MS & Moore FR. (1997). Age-related differences in the stopover of fall landbird migrants on the coast of Alabama. Auk. vol 114, no 4. p. 695-707.