Nashville Warbler Life History

Habitat

Habitat Forests

Throughout the year, Nashville Warblers use shrubby, second-growth habitats. On the breeding grounds, the eastern subspecies requires mixed-species forests, tamarack, spruce, or scrub oak. The western subspecies can be found in brushy black-oak groves, often between 3,300 and 5,400 feet in elevation. They readily take to regenerating clearcuts that are between 30 and 60 years old. Wintering habitat for both populations is primarily low, open deciduous and mixed tropical forests, and it is a regular visitor to suburban gardens. Nashville Warblers are flexible in migration, frequenting nearly any brushy habitat. In the West they frequent drier habitats such as desert flats and washes, in fall but not in spring.

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Food

Food Insects

The Nashville Warbler eats almost exclusively insects and other arthropods in all seasons. Overwintering birds in the southern United States will sometimes come to suet cakes. Specific food items include flies, grasshoppers, leafhoppers, caterpillars, beetles, and spruce budworms.

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Nesting

Nest Placement

Nest Ground

The Nashville Warbler nests on or near the ground. The nest is well hidden among bushes or at the base of trees.

Nest Description

The female builds the nest, taking 7–9 days to complete it. Nest is a neat cup of moss, strips of bark, and grasses. It is lined with fine grasses, pine needles, and animal hair. The nest is about 3.5 inches across and 2 inches deep.

Nesting Facts

Clutch Size:4-5 eggs
Number of Broods:1 brood
Egg Length:0.6-0.7 in (1.4-1.7 cm)
Egg Width:0.4-0.5 in (1.1-1.3 cm)
Incubation Period:11-12 days
Nestling Period:9-11 days
Egg Description:White, usually specked with brown.
Condition at Hatching:Helpless with some sparse dark brown down.
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Behavior

Behavior Foliage Gleaner

The Nashville Warbler moves deliberately as it forages, sometimes flicking its tail. It moves among the tips of branches and picks at insects on the underside of leaves. In the eastern population, males sing in the middle to lower understory. Western birds sing from high, exposed perches, occasionally from the tops of old burned trees. Pairs are seasonally monogamous with no evidence of extra-pair copulation or polygamy. Females incubate, though the male helps some and both parents feed the chicks. While Nashville Warblers maintain individual territories during the breeding season, the rest of the year that are quite gregarious, forming large mixed-species flocks during migration and in the winter.

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Conservation

Conservation Low Concern

Nashville Warbler populations were stable between 1966 and 2015 according to estimates from the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 40 million and rates the species a 9 out of 20 on the Continental Concern Score, indicating a low conservation concern. Clearing of forested land may benefit this species by creating more of the second-growth habitat in which it nests, making it less vulnerable to habitat changes than many other Neotropical migrants.

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Credits

Lowther, Peter E. and Janet Mcl. Williams. (2011). Nashville Warbler (Oreothlypis ruficapilla), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Lutmerding, J. A. and A. S. Love. (2019). Longevity records of North American birds. Version 1019 Patuxent Wildlife Research Center, Bird Banding Laboratory 2019.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Stephenson, T. and S. Whittle (2013). The Warbler Guide. Princeton University Press, New Jersey, USA.

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