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Wood Stork

Mycteria americana

Listing Status

  • Federal Status: Threatened
  • FL Status: Federally-designated Threatened
  • FNAI Ranks: G4/S2 (Globally: Apparently Secure; State: Imperiled)
  • IUCN Status: LC (Least Concern)

Appearance

The wood stork is a large, long legged wading bird that reaches a length of 35-45 inches (89-114 centimeters) with a wingspan of 60-65 inches (152-165 centimeters).  The primary and tail feathers are black (J. Rodgers pers comm. 2011).  The head and upper neck of adult wood storks have no feathers, but have gray rough scaly skin.  Wood storks also have a black bill and black legs with pink toes.  Adult wood storks are voiceless and are capable of only making hissing sounds. 

Behavior

wood stork

Wood storks feed on small to medium-sized fish, crayfish, amphibians, and reptiles.  Their hunting technique is unique as they will move their partially opened bill through water, snapping up prey when the prey comes in contact with the bill.

The wood stork is the only species of stork that breeds in the U.S..  Wood storks are very social in nesting habitats, as they are often seen nesting in large colonies of 100-500 nests.  Colonies in South Florida form late November to early March, while wood storks in Central and North Florida form colonies from February to March (Florida Natural Areas Inventory 2001).  After copulation, males begin gathering twigs for constructing nests (Coulter et al. 1999).  Wood stork nests are primarily built in trees that stand in water (U.S. Fish & Wildlife Service 1999).  In Florida, wood storks are capable of laying eggs from October to June (Rodgers 1990).  Females lay a single clutch of two to five eggs per season (U.S. Fish & Wildlife Service 1999).  The average incubation period is 30 days, with young wood storks able to fly 10-12 weeks after hatching (J. Rodgers pers comm. 2011).

Habitat

wood stork map

Wood storks nest in mixed hardwood swamps, sloughs, mangroves, and cypress domes/strands in Florida (Florida Natural Areas Inventory 2001).  They forage in a variety of wetlands including both freshwater and estuarine marshes, although limited to depths less than 10-12 inches.  The wood stork breeds in Florida, Georgia, South Carolina, and North Carolina.  Non-breeding wood storks have an extensive range throughout North America, to northern Argentina in South America (Florida Natural Areas Inventory 2001, J. Rodgers pers. comm. 2011). 

Threats

The South Florida population has collapsed due to agricultural expansions and altered hydrocycles (Coulter et al. 1999, J. Rodgers pers comm. 2011).  Wood storks need normal flooding to increase prey population with a natural drawdown to concentrate prey in one area (J. Rodgers pers comm. 2011).  Successful breeding depends on normal hydrocycles.  The drainage of cypress stands prevents the wood stork from nesting, and promotes predation from raccoons (U.S. Fish & Wildlife Service 1996). 

Conservation and Management

The wood stork is protected by the U.S. Migratory Bird Treaty Act.  It is also protected as a Threatened species by the Federal Endangered Species Act and as a Federally-designated Threatened species by Florida’s Endangered and Threatened Species Rule. The wood stork was reclassified by the U.S. Fish and Wildlife Service on June 30, 2014, from Endangered to Threatened.

Federal Recovery Plan

References

Coulter, M. C., J. A. Rodgers, J. C. Ogden and F. C. Depkin. 1999. Wood Stork (Mycteria  americana), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of       Ornithology; Retrieved from the Birds of North America Online.

Florida Natural Areas Inventory. 2001.  Field guide to the rare animals of Florida.    http://www.fnai.org/FieldGuide/pdf/Mycteria_americana.PDF.

Rodgers, J.A., Jr. 1990. Breeding chronology and clutch information for the wood stork 
from museum collections. Journal of Field Ornithology 61(1):47-53.

U.S. Fish & Wildlife Service.  1996. Revised recovery plan for the U.S. breeding population of the wood stork.  U.S. Fish & Wildlife Service. Atlanta, Georgia. 41p.

U.S. Fish & Wildlife Service. (n.d.). Wood stork. Retrieved August 23, 2011, from Multi-Species Recovery Plan for South Florida: http://www.fws.gov/verobeach/MSRPPDFs/Woodstork.pdf.