Wood Stork FAQ

Do you have questions about wood storks? Read the wood stork FAQ for answers.

Are wood storks really storks?
Yes, although the wood stork we are familiar with here in Florida looks nothing like the European white stork most people think about when they hear the name stork, the wood stork is a true stork. It is one of only 17 species of storks in the family Ciconiidae that are generally distributed throughout the temperate and tropical regions of the world. Storks, herons, ibises, and New World vultures are placed in the avian order Ciconiiformes. Recent DNA analysis suggests storks and New World vultures are more closely related to one another than storks are related to ibises and herons.

Do wood storks deliver babies?
There is no evidence that wood storks deliver babies.

Where do wood storks occur?
The species is a common nesting bird from coastal Mexico and northern Argentina throughout interior South America, the Caribbean islands of Cuba and Hispaniola, north to the southeastern United States, including Florida, Georgia, and South Carolina. Florida has the largest nesting population in the U.S. Non-breeding and migratory storks occur in southern California, southern Texas and Louisiana, along the Atlantic coast as far north as Delaware Bay, and along the Mississippi drainage as far north as Missouri.

What do wood storks feed on?
Wood storks feed on a variety of prey items including fish, frogs, crayfish, large insects, and occasionally small alligators and mice. However, fish make up the bulk of their diet, especially fish ranging in size from 1-6 inches. This means that storks feed on larger fish that require more than one season or year of growth. The implication is that these prey require wetlands that are flooded for greater than one year and infrequently dry up completely.

I have seen some people feeding hotdogs and chicken wings to wood storks and other wild animals. Should I feed wood storks?
No. It is never a good idea to feed wildlife. The result is an animal that becomes acclimated to humans, which often results in an adverse wildlife-human interaction and dependence upon the supplemental feeding to survive. Storks that are fed by people may become panhandlers and be a problem later when the feeding stops, which requires intervention by wildlife personnel. Finally, artificial food items such as hotdogs and chicken wings are woefully deficient in vitamins and minerals that are required for proper nutrition.

I often see wood storks with chalky white-colored legs. What causes this color?
Normally the legs of wood storks are black, however, an observant person may occasionally notice the lower half of their legs are covered with a white-colored material during the warmer parts of the year. This is especially noticeable when storks are incubating eggs or young nestlings and they can not move away from their nests and into the shade. Storks will defecate on their legs, especially when they have to stand in the sun while tending their nest. This behavior is thought to be a cooling mechanism that uses the highly vascularized legs and cooling effect of the evaporating moisture. The guano (the scientific word for bird feces, which is more of a chalky, watery consistency) is washed off their legs when they forage in water and appears to have no pathological effect on the skin. A similar cooling effect is attained when a person wipes their body with a moist towel.

Where can I go to see wood storks breeding?
Most wood stork colonies are located either on private lands or far back in swamps that do not permit ready access to see these nesting birds. Less common coastal colonies are more accessible to boat traffic. However, we recommend that you use binoculars when observing these nesting birds and maintain a minimum of 100 yards from the colony. The best place to see nesting storks in Florida is at the Corkscrew Swamp Sanctuary maintained by the National Audubon Society near Naples.

Why should I maintain the recommended 100-yard buffer when observing wood storks?
Most birds require a minimum distance between a potential predator or approaching human before they abandon their nests. Causing storks to flush from their nests will expose the eggs or young nestlings to over-heating due to the effects of the sun or the stress due to cooling during cooler temperatures or inclement weather. The defenseless and exposed eggs and young birds also are exposed to aerial predators such as crows, which often are alerted to the disturbance caused by humans and quickly swoop in and pillage the nest contents. Finally, disturbed older nestlings may try to escape and fall from the nest or tree. Adults will not feed these young and they face an almost certain death.

How far away from a colony will wood storks fly in order to find food for their young?
Based on several studies, both in Georgia and Florida, using wood storks with attached radio-transmitters that send signals to allow the location of the individual birds, it appears that storks regularly fly distances of 5-12 miles from the nesting colony during regular foraging bouts. However, one stork flew about 75 miles away and returned the following day to relieve its mate and feed its nestlings! The distance a stork flies to locate food is dependent upon water levels, the availability of prey, and quality of wetlands. During droughts, storks must fly greater distances in order to find food. Thus, the wetlands around the colony site are important in maintaining the feeding habitat and integrity of a successful nesting effort.

If I know of or see a colony of wood storks, should I notify anyone?
Most of the wood stork colonies in Florida, Georgia and South Carolina are known to wildlife agencies as a result of intensive aerial and ground surveys by their personnel. However, we frequently are alerted to the location of unknown or new nesting colonies of storks by the public. Please contact us at Storks@MyFWC.com.

Why do wood storks have the word "wood" in their name?
Wood storks have a variety of common names, hence the frequent use of the scientific or Latin name Mycteria americana to avoid confusion. "Wood" probably refers to their nesting sites being located in the woods or swamps. Other common names include wood ibis (due to the similarity of the down-curved bill of ibises) and flinthead (due to the lack of feathers on the head and instead possessing large, scale-like patches typical of adults). Use of the word "Mycteria" in the scientific name is Greek for nostril, or to sneer, which is derived from the large down-curved bill of the species.

At what age do wood storks begin to breed?
Based on banded and known-age birds, wood storks do not enter their first breeding season until they attain a minimum of three years of age. However, most storks do not begin breeding until they are four years of age. Thereafter, they probably nest once a year.

About how long do wood storks live?
We do not know much about the longevity of wood storks. We believe they generally live to be 11-18 years old in the wild. The oldest wood stork in captivity lived to be 27 years and 6 days old.

What are some of the factors that result in the death of wood storks?
Let's examine sources of stork mortality at two levels: First, breeding-related mortality of the eggs and nestlings is a common phenomenon. Of the average clutch size of 3 eggs per nest, only about 1.3 nestlings survive to become independent and fly from the nest. Thereafter, survival rates of these fledglings once they leave the nest is unknown. Known factors causing egg or nestling loss are predators, nest collapse during storms, and insufficient food supplies which results in starvation when parents can not capture sufficient prey. Second, mortality of adult storks also is due to a variety of causes. Factors that have been identified to cause the death of adults include predators (such as alligators and bobcats), pesticide poisoning, collisions with power lines, and being struck by automobiles while taking off across the road. Disease also probably plays an unknown role in the death of both young and old storks.

How can you tell the difference between a male and female wood stork?
There are no obvious differences in the plumage that will allow you to distinguish between male and female wood storks. However, males are slightly larger than females (males average 7.1 pounds, females average 6.1 pounds) and have a heavier, longer bill (males average 9 inches to a female average of 7.5 inches).

How many eggs do wood storks lay?
The clutch size (number of eggs laid) of wood storks range from 1-5 eggs, with 3 eggs being the most common number of eggs in a nest. The eggs are a flat-white in color and similar in size to an extra large chicken egg. If the first clutch is lost early in the nesting season, a female may lay a second clutch if she has enough body reserves. Usually the second clutch size contains fewer eggs.

How old are wood storks when they leave their nest or colony?
Wood stork nestlings are fully feathered and capable of short flights at about 7-8 weeks of age but are not independent of their parents until they are 9-10 weeks old. The fledglings then leave the colony at 10-12 weeks of age. Thereafter, they do not interact with their parents. Immature storks spend the next 3-4 years wandering until they reach reproductive maturity. Only rarely will these young adult storks be seen in colonies and then mostly in small numbers; however on occasion they will group together in a gang and disrupt the nesting activities of the adults.

Do both parents take care of the nestlings?
Yes, both males and females share incubation (sitting on eggs) and brooding (taking care of the nestlings) duties.

I have occasionally seen wood storks soaring at great altitudes while flying my private plane. Why are they flying so high?
Whereas storks are slow to take off in flight, requiring deep laborious wing beats to gain altitude due to their size and weight, they are graceful fliers once in flight and excellent high altitude fliers. Storks frequently seek out thermals (the upward convection of warm, rising air) during the summer months, which allows storks to attain great heights with little wing flapping. The use of thermals greatly conserves energy compared to flight with wing-flapping. Once they reach the desired height, the storks will glide with little wing-flapping for great distances toward their foraging sites. Occasionally, storks will use a series of thermals (thermal hopping) to get to their ultimate destination, similar to humans flying gliders.

What type of trees do wood storks use for nesting?
Storks nest in a variety of both native and exotic species of trees and generally can be described as requiring woody vegetation in water or surrounded by water in the case of an island. Native species include cypress, gum, willow, oaks, wax myrtle, both red and black mangrove, and red maple. Non-native or introduced species include Brazilian pepperbush and Australian pine, especially in south Florida. Suitable nesting substrate, also known as a base, must be strong enough to support the rather large nest, one or both members of the pair, and nestlings. This usually requires the tree to be both tall and possess large limbs where the nests are located. Storks usually build their nests in trees flooded by 1 to 3 feet of water or surrounded by water in the case of islands. At interior freshwater sites, these flooded trees provide a water barrier to ground predators such as raccoons and snakes. This water moat around the nest trees also allows the 24-hour patrol by alligators that further reduces the chance of a raccoon swimming to a nest tree.

What type of nest do wood storks build?
Storks build a rather bulky nest of twigs that are simply laid in the forks of trees or on a branch of a tree. Nest height above the water varies from 3- to 50- feet. Nests generally are 20- to 25-inches in diameter and 6- to 10-inches high. The foundation material usually is made up of larger dead sticks (up to 2- inches thick) while the upper surface of the nest contains smaller (1/16- to 1/8-inch thick), more pliable twigs. While most of the nest is rather porous, the interior surface or cup region is lined with live vegetation made up of leaves and pliable branchlets. This nest greenery lines the cup region to prevent the eggs from slipping down into the spaces between the large twigs and further insulates the eggs in the rather porous nest. Finally, the habit of storks to defecate over the edge of the nest deposits a layer of guano around the edge of the nest, which dries to form an almost adobe material. It also provides some strengthening and rigidity to the lattice, or framework of twigs.

What sounds or calls do wood storks make?
Nestlings make a variety of calls mostly associated with being uncomfortable (when a brooding parent raises off the nestlings, for example) or when begging for food from their parents. From hatching until about 2-weeks of age, nestlings utter a long series of repetitive raspy "heh-heh" calls. Once they attain the age of 2-weeks, nestlings utter a repetitive series of nasal "haw-haw" calls. This call is audible from several hundred feet away and is useful in locating a large stork colony from the ground. However, adult storks don't really utter a call. Rather, they make either hissing sounds or loud popping sounds by snapping their bills during aggressive interactions or courtship activities.



FWC Facts:
Many species of fish (many groupers, snook, etc.) are hermaphroditic and change sex at some point in their life.

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