Wood Stork Conservation
The Southeastern U.S. population of wood storks (Mycteria americana) is listed as endangered under the Endangered Species Act (ESA) and is fully protected by Florida and Georgia state laws. The principle reason for the ESA listing is related to its decline from an estimated 20,000 nesting pairs in the 1930s to a low of about 3,000-5,000 pairs in the 1970s. In 1999, a new wood stork rookery formed on Zoo grounds and it soon began to show signs of annual growth. This was brought to the attention of the U.S. Fish and Wildlife Service (USFWS) and resulted in Jacksonville Zoo and Gardens (JZG) attending the 2002 annual meeting of the Wood Stork Research and Monitoring Working Group. At this meeting, a monitoring protocol was proposed by the Florida Fish and Wildlife Conservation Commission (FWC) - and later USFWS. As a result, the Jacksonville Zoo and Gardens’ Wood Stork Conservation Project and Partnership was signed by JZG and USFWS in 2003. Careful monitoring started in 2003. Due to the JZG’s acclimated birds and close proximity of the rookery to the African exhibits elevated boardwalks, the Zoo is able to monitor nests twice weekly.
Banding of nestlings began in 2003. In 2004, JZG began satellite tagging and banding of adult wood storks. Captured adults were banded with United States Geological Survey bands, a rookery color-coded numbered band, and a large white or blue band with no numbers denoting the bird was banded as an adult. The genders of the adult wood storks were determined using DNA techniques. The program plans to use banded storks to monitor nest attendance by sex and to determine the site fidelity of the species.
JZG has provided veterinary care for injured wood storks since the rookery’s inception. In 2003 eight educational graphics were placed around the rookery to tell the story and status of the species. The graphics also change to report on the rookery status from year to year. JZG’s rookery is used by our Education Department’s Summer, Holiday and Spring Break Camp programs that reach over 700 children annually. Zoo staff and volunteers have spent hundreds of hours monitoring the rookery.
Since the annual growth of the rookery has filled the available trees, JZG has constructed and installed artificial nesting sites, based on the design in use at the Harris Neck Wildlife Refuge, near the rookery and in another area on Zoo grounds to provide additional nest sites for future expansion. During 2006, when it appeared that we would loose the largest of the rookery trees because of earlier lightening strikes, JZG expended additional funds to save as much of that nesting tree as possible as well as adding bald cypress trees that will fill the gaps as the older trees die. JZG has taken great pride in our rookery as one of the most productive in the State of Florida over the last six years measured by its fledgling rate, and it is considered an important conservation and educational component of the Zoo.
Since the beginning of the project, JZG has banded 121 chicks of the 1,299 fledged chicks and has banded 14 adults, with 9 wearing satellite-monitoring tags. The satellite data provided by JZG to the USFWS has directly aided their wood stork regulatory efforts in the region. All 9 of the earlier banded adults returned every year to this nest site until 2007, when some did not. Site fidelity had not been recorded in other larger rookeries to date. In 2006, JZG observed two chicks banded in 2003 returning to the rookery and performing mock copulation and nest building. The JZG rookery is unique in its accessibility giving the zoo the ability to closely monitor all birds in the colony. No other site has this unique ability and this allows us to record data unobserved in any other colony. Although our sample size is still low, it is significant that we have such a high survival rate particularly within the adult population. As the project continues, we hope to see more returning chicks allowing for some estimation of chick survivability between fledging and sexual maturity. USFWS is funding a contaminants study to begin in 2007 including the capture and satellite tagging of an additional 6 adult wood storks.
Over the last six years (2003-2008) the JZG rookery has been one of the most productive in the Southeastern U.S. with a 6-year average of 2.53 chicks per nest as compared with the Recovery Plan criteria goal of 1.5 chicks per nest. Feather analysis of the banded chicks suggests that the primary food sources being fed to the chicks is fresh water prey items not zoo food items or estuarine prey. Satellite tracking data to date supports this foraging pattern, with adults feeding primarily on an estuarine prey base prior to nesting, switching to fresh water prey base during chick rearing, and then return to an estuarine diet after chick fledging and during the rest of the year. Annual reports to USFWS and FWC have resulted in the expansion of our program by USFWS. USFWS publications have published data from the JZG rookery. Other papers and posters have been presented, including at AZA conferences. JZG has been recognized by the Department of the Interior for our colonies unique ability to be used as a working laboratory. The JZG colony provides valuable information on the urbanization of this species and will aid in the update of the USFWS Wood Stork Recovery Plan.
|1999||7 pairs form rookery||Observations begin by Senior Keeper of Birds|
19 chicks fledged
|Zoo staff begins providing veterinary care for chicks|
45 chicks fledged
|Senior Keeper continues monitoring the growing colony|
111 chicks fledged
|USFWS aware of colony. JZG begins attending Wood Stork Research and Monitoring Group Meetings|
191 chicks fledged
|JZG signs Wood Stork Conservation Project and Partnership with USFWS and begins monitoring the rookery. Artificial nest platforms installed around the colony and the Zoo.|
208 chicks fledged
|24 chicks & 3 adults banded. First adult satellite tagged and released (media in attendance).|
219 chicks fledged
|28 chicks & 4 adults banded. Adult & chick satellite tagged.|
267 chicks fledged
|28 chicks & 2 adults banded. Nesting tree salvage. Planting of new nesting trees.|
58 chicks fledged
|1 adult banded. 2 adults satellite tagged.|
181 chicks fledged
|41 chicks banded. 3 adults satellite tagged.|
124 chicks fledged
276 chicks fledged
|24 chicks banded.|
New Directions 2007-2009
One of the steps identified to help in wood stork recovery is to assess potential contaminant risks to the storks. Man-made constructed wetlands are increasing across the wood stork’s range while natural wetlands and marshes are decreasing rapidly. These constructed wetlands often serve to protect natural water bodies by collecting runoff contaminated with fertilizers, pesticides and oils that originate from surrounding landscapes. Previous studies have shown that storks from the Jacksonville Zoo and Gardens nesting colony use natural marshes and tidal areas during the breeding season, but forage in constructed wetlands during nesting and fledging. Whether these constructed wetlands are a benefit or risk for wood storks is unknown. Therefore, in 2007 and 2008, the Jacksonville Zoo and Gardens began a new project with the U.S. Fish and Wildlife Service to determine actual use of constructed wetlands by wood storks and to determine the habitat quality of the constructed wetlands by examining the levels of contaminants in soils, prey and salvaged wood stork chicks. This project is funded by the U.S. Fish and Wildlife Service, in cooperation with the Jacksonville Zoo and Gardens and the University of Georgia.
The U.S. Fish and Wildlife Service supported JZG in nest monitoring efforts, provided assistance via installation of artificial nest platforms, and provided advice and logistical support for the banding/tagging and satellite tracking program. In 2007 USFWS has provided funding for six more satellite tags and toxicology testing of wood stork foraging sites. Florida Fish and Wildlife Conservation Commission provided protocol and supported nest monitoring. Savannah River Ecology Lab provided permitting, advice and logistical support of the banding/tagging and satellite tracking program. Harris Neck Wildlife Refuge provided the design and aided in the installation of artificial nest platforms. Duval Audubon Society provided funding for graphics surrounding the rookery, and volunteers to assist with nest monitoring and chick banding.
The University of North Florida continues to assist with chick banding by providing a 60-ft. bucket truck and driver to allow staff to reach the young chicks in their nests.
For more information see the FWS’s wood stork site.