Magnolia Warbler Life History

Habitat

Habitat Forests

Magnolia Warblers breed in dense stands of young conifer trees, especially spruce in the north and hemlock in the south. During migration they forage in dense areas along forest edges, woodlots, and parks. On the wintering grounds, they occur from sea level to 5,000 feet in a variety of areas including cacao plantations, orchards, forests, and thickets.

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Food

Food Insects

Magnolia Warblers primarily eat caterpillars, especially spruce budworm when it is abundant. They also eat insects and spiders and occasionally take fruit in the fall. They tend to forage on the outer edges of branches, searching the undersides of needles and leaves for prey.

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Nesting

Nest Placement

Nest Tree

Magnolia Warblers nest in dense conifers such as spruce, balsam fir, and hemlock. The nest is typically on a horizontal branch close to the trunk of the tree and is less than 10 feet above the ground.

Nest Description

Males and females weave together a sloppy and flimsy-looking nest of grasses and weed stalks built on a foundation of twigs. They line the nest with horsehair fungus.

Nesting Facts
Clutch Size:3-5 eggs
Number of Broods:1-2 broods
Egg Length:0.6-0.7 in (1.5-1.8 cm)
Egg Width:0.4-0.5 in (1.1-1.3 cm)
Incubation Period:11-13 days
Nestling Period:8-10 days
Egg Description:White, with variable speckles or spots.
Condition at Hatching:Helpless with tufts of black down.
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Behavior

Behavior Foliage Gleaner

Magnolia Warblers hop from branch to branch in dense stands of young conifer trees. They pick insects primarily from the undersides of conifer needles and foliage. Males sing most intensely at dawn and dusk and even sing while foraging. Males court females with song and show off the white spots on their tail, similar to the behavior of an American Redstart. To warn a territory intruder, males also spread their tail, flashing their white tail spots. Males and females maintain a shared territory on the breeding grounds, but separate territories on the wintering grounds. During migration they frequently join foraging flocks of chickadees, and they join mixed-species flocks on the wintering grounds.

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Conservation

Conservation Low Concern

Magnolia Warblers are common and their populations increased by almost 1% per year from 1966 to 2015, according to the North American Breeding Bird Survey. Partners in Flight estimates the estimated global breeding population at 39 million. The species rates a 7 out of 20 on the Continental Concern Score, which means it is not on the Partners in Flight Watch List and is a species of low conservation concern.

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Backyard Tips

Magnolia Warblers do not visit feeders and may only stop off in your yard during migration, but you can still provide habitat for them by landscaping with native trees and shrubs. A bird-friendly backyard full of native trees and shrubs provides an excellent food-rich place for warblers and other migrants to stop and refuel. Head on over to Habitat Network to learn about which native species are good matches for your yard and read more about growing native plants for warblers.

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Credits

Dunn, Erica H. and George A. Hall. 2010. Magnolia Warbler (Setophaga magnolia), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Lutmerding, J. A. and A. S. Love (2016). Longevity records of North American birds. Version 2016.1. Patuxent Wildlife Research Center, Bird Banding Laboratory, Laurel, MD, USA.

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

Pieplow, N. (2017). Peterson field guide to bird sounds of eastern North America. Houghton Mifflin Harcourt Publishing Company, NY, USA.

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, USA.

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

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