Wood Stork Life History

Habitat

Habitat Marshes

Wood Storks breed in fresh and brackish forested wetlands. They forage in wetlands, swamps, ponds, and marshes with water depths of around 4–12 inches. They tend to use open wetlands more frequently for foraging than closed canopy wetlands. Storks roost in trees along the water's edge.

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Food

Food Fish

Wood Storks primarily eat fish and other aquatic invertebrates, but sometimes take seeds, amphibians, nestlings, and reptiles. They walk slowly through wetlands with their bill in the water, feeling for prey. When they feel something on their bill, they quickly snap it closed, swallowing the prey whole. To find prey they also push their feet up and down in the water or flick their wings to startle prey. Storks also visually search for prey, but more frequently use their bill to feel for it, especially in muddy waters.

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Nesting

Nest Placement

Nest Tree

Wood Storks nest in trees above standing water. They build nests in cypress swamps, in oaks in flooded impoundments, in mangroves, and in flooded areas with black gum and Australian pine. Almost any tree or shrub will do as long as standing water is present.

Nest Description

Males and females gather sticks from the surrounding areas. Together they build a large, bulky stick nest 3–5 feet wide. They line the nest with greenery that eventually gets covered in guano, which helps hold the nest together. Nest building typically takes 2–3 days, but the pair continues to make improvements throughout the nesting period.

Nesting Facts
Clutch Size:1-5 eggs
Number of Broods:1 brood
Egg Length:2.4-2.9 in (6.1-7.3 cm)
Egg Width:1.3-2.2 in (3.4-5.5 cm)
Nestling Period:50-55 days
Egg Description:

Creamy white.

Condition at Hatching:

Nestlings are covered in fine white down except on the head.

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Behavior

Behavior Probing

Wood Storks are social birds that forage in groups and nest in colonies. Small groups of storks forage in wetlands, frequently following each other one by one in a line. In the late afternoon, when temperatures rise, Wood Storks often take to the sky, soaring on thermals like raptors. They nest in tight colonies with egrets and herons and generally show little aggression, but if a bird or mammal threatens them, they may pull their neck in, fluff up their feathers, and walk toward the intruder. Threats are also met with bill clattering and jabbing. Despite the myth that Wood Storks mate for life, pairs form at the breeding colony and stay together only for a single breeding season. Males initially are hostile to the female, but once he accepts her into the territory he starts preening her and offering her sticks.

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Conservation

Conservation Low Concern

Wood Storks are uncommon in the United States. Their populations remained stable from 1966 to 2015, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 450,000. The species rates a 12 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. However, because Wood Storks occur only in a small portion of the United States, the U.S. Fish and Wildlife Service lists them as federally threatened. Wood Stork populations are vulnerable to changes in water levels. During dry years or in years when extensive water diversion projects reduce the amount of standing water below nest trees, a colony may forgo nesting. Low water levels can also increase nest predation from terrestrial predators such as raccoons. Lower water levels also affect foraging opportunities as fewer prey are available.

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Credits

Coulter, M. C., James A. Rodgers Jr., John C. Ogden and F. C. Depkin. 1999. Wood Stork (Mycteria americana), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, 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.

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.

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