Wood Storks & Wetlands UCF Jan. 26, 2010 Jason Lauritsen Asst. Director Corkscrew Swamp Sanctuary
Stork Overview 1984 on Endangered Species List South Carolina, Georgia, Alabama & Florida Mature at 3-4 years Feeds by touch Nests in colonies (cypress, mangrove, other) Feeds on fish & invertebrates 1 st year critical, may live 11+ years Can fly (soar) over 50miles from nest to feed
Nesting Range Wood Stork Overview Feeding Survival
Population History Prior to the 1970 s about 70% of US storks nested in South Florida Total nests in US: 1930 s ~ 20,000 pairs 1960 s ~ 10,000 nesting pairs Late 70 s ~ 5000 nesting pairs
USFWS 5-year Status Review Sept. 28 th 2007 recommended upgrading status from Endangered to Threatened Northern/coastal range is stable or improving Southern range is unstable
Wood Stork Nesting at Corkscrew 18000 16000 14000 Nest Numbers 12000 10000 8000 6000 4000 2000 0 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Year No. of Nesting Pairs No. of Birds Fledged
Core Foraging Area (18.6 miles)
Wood Stork Nesting at Corkscrew 18000 16000 14000 Nest Numbers 12000 10000 8000 6000 4000 2000 0 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 Year No. of Nesting Pairs No. of Birds Fledged
1961 & 1966 ~ 6000 pairs nested at Corkscrew ~2.6 million lbs of fish to supply those nests (440lbs/nest)
Loss of about 35% of wetlands in S. Florida
Nature of Historic Wetland Losses: Roads & Canals Resource Inventory and Analysis, Big Cypress National Preserve. Vol. 1. 1979 1900 1920 1930 1950 1960 1970
Historic development pattern in SWFL Avoided deep wetlands Drain shallow wetlands (ditches/canals/lakes) Build in shallow wetlands
Wetland Losses within the CFA From pre-development to 2004 Total 44% Short hydroperiod 62% (73-52%)* Long hydroperiod 19% (34-7%)* Tidal 10% *not all wetland data from the 2004 Land Cover map had hydroperiod data.
How do they work? Flat topography Rainy season Dry season cycle Floods, droughts, hurricanes, fires
hydric pine flatwoods wet prairie cypress deep marsh 1-2 months, 6 inches 2-6 mo.12 in. 6-8 mo. 18 in. 6-10 mo. 24 in. September December March
Gator holes act as dry season refuges for aquatic fauna
South Florida dry-season & Stork nesting Storks arrive in October Should start nesting in Nov/Dec Storks wait for foraging sites to recede to 2-16 Storks need a 4 months window for nesting success Loss of Oct-Dec wetlands shifts foraging later in year
Productivity decline preceded shift in nest timing. Since 1979 storks only nest early during hyper-wet years
Audubon Research Wood stork foraging habitat assessment for SWFL Foraging locations Aerial surveys, follow-flights GPS tags on nesting storks Foraging quality Prey sampling Will lead to growth tools & policy recommendations
Satellite tagged storks: 5 tagged birds in area 4 nesting at Corkscrew One bird from SWA colony 5 more tags to deploy Position data: Habitat use data 18 positions/day Multiple years Enhance follow-flights Establish C.F.A.
Oct 06 Jan 07 Feb June 07
Stork habitat use in SWFL Early nesting season - few natural feeding sites remain, often forage in altered locations - ditches, ag fields etc. Mid-late nesting season - majority of foraging sites in natural wetlands
Habitat Use Corkscrew B-staff gauge 05-06 20.00 19.00 Water Level (ft. NGVD 29) 18.00 17.00 16.00 15.00 14.00 13.00 12.00 1/1/05 2/1/05 3/1/05 4/1/05 5/1/05 6/1/05 7/1/05 8/1/05 9/1/05 10/1/05 11/1/05 12/1/05 1/1/06 2/1/06 3/1/06 4/1/06 5/1/06 6/1/06 7/1/06 8/1/06 Date
Oct Dec. foraging Ditches, lake edges, canals, stormwater ponds
Wood Stork Foraging along Corkscrew Road Photo taken 10/17/08 Photo taken 10/17/08 Photo taken 11/18/08
Foraging Wood Storks on RCH mine photos taken on 11-19-08 69 wood storks documented foraging in these ditches, in 1 event
Oct-Dec. Foraging in Ag WOST foraging Assessment 2006-07
Mid-late season foraging Cypress, donut holes, open marsh
Storks are routinely foraging in forested wetlands
Development in SWFL
Future stork population trends in South Florida: If they initiate nesting early (Nov.-Dec) 28% increase over next 30 years If they continue to nest late (late Jan-Mar.) 38% decrease over next 30 years Unpublished study by Rena Borkataria, U of F
In a Nutshell SWFL s wood stork colonies are increasingly at risk We ve lost & continue to lose too many shallow wetlands this makes storks nest later in the year To stabilize or recover them we need to restore/protect these shallow wetlands (used by storks from Oct.- Jan.)
Special Thanks to: Ed Carlson Brad Cornell David Ceilley Ann Marie Lauritsen Mike Duever Mike Knight Shawn Liston USFWS SFWMD Beaver Aviation Ralph Arwood Larry Bryan Rena Borkhataria