1. Current Trends in Florida Scrub-Jay Populations
Todd Mecklenborg
Recovery Biologist

2. Background
Hiram Byrd first noted declines in Florida scrub-jay populations.

3. Jay Declines 39 counties had scrub-jays
It turns out that what makes jays special also makes them vulnerable. Scrub-jay populations have been declining for decades throughout the state.
Scrub-jays once occupied 39 of the 40 counties south of, and including Levy, Gilchrist, Alachua, Clay, and Duval Counties. Only the southernmost county, Monroe, lacked scrub-jays.

4. Jay Declines Now missing from 8 counties (red)
39 counties had scrub-jays
Now missing from 8 counties (red)
Extirpated prior to 1984
Broward
Dade
Duval
Gilchrist
Pinellas
St. Johns
Extirpated after 1984
Alachua
Flagler
By extirpated from Broward, Dade, Duval, Gilchrist, Pinellas, and St. Johns Counties.
Now Alachua, and Flagler Counties no longer have scrub-jays.

5. Jay Declines Few left in 17 counties (hatched)
39 counties had scrub-jays
Now missing from 8 counties (red)
Few left in 17 counties (hatched)
Counties with fewer than 2 groups
Clay
Levy
Orange
Putnam
Hillsborough
Clay, Levy, Orange, and Putnam Counties have had less than 2 scrub-jay groups observed over the last several years.

6. Jay Declines
39 counties had jays
Now missing from 8 counties (red)
Few left in 17 counties (hatched)
Only 9 counties have > 30 family groups on conservation lands (green)
Other counties have very few or no jays on public lands
Citrus, Hendry, Hernando, Pasco, Seminole, Sumter

7. Extirpated, Nearly or Already Extirpated, and Dwindling

9. Population Trends Late 1800’s ~ 31,200 - 45,600 scrub-jays.
Jeffrey Cox estimated between 15,600 to 22,800 scrub-jays remained.
Statewide Survey (John Fitzpatrick et al.) estimated 10,972 individual scrub-jays (3,961 scrub-jay groups).
2011 (Raoul Boughton and Reed Bowman) estimated 2, ,600 scrub-jay groups excluding Ocala National Forest.

10. STATUS TOTAL GROUPS 3,003 3,753 Conservation lands
Low estimate
High estimate
Source/Comment
Conservation lands
(excluding Ocala NF)
1,253
Boughton and Bowman 2011
Ocala National Forest
1,000
1,250
Estimate based in part on Miller and colleagues (unpublished data)
Private lands
750
Rough estimate, assumes either a 50% or 70% decline
TOTAL GROUPS
3,003
3,753
INDIVIDUALS
9,009
11,259
Assumes average group size of 3

11. Population Size, # of individuals
Population Trends
Population Size, # of individuals
Year
Late 1800’s ~ 31, ,600 scrub-jays.
Jeffrey Cox estimated between 15,600 to 22,800 scrub-jays remained.
Statewide Survey (John Fitzpatrick et al.) estimated 10,972 individual scrub-jays (3,961 groups).
2011 (Raoul Boughton and Reed Bowman) estimated 2, ,600 on managed public lands excluding Ocala National Forest. By adding estimates for Ocala National Forest and private lands, get the statewide estimate shown here.

12. Jay Declines 25% decline on conservation lands since 1992-93.
Most far below carrying capacity.
Estimated 3,094 70% carrying capacity.

13. Populations & Metapopulations
A population is a group of Florida scrub-jays living in the same defined area.
Florida scrub-jay metapopulations are groups of populations that are separated spatially, but among which dispersal occurs (7.5 mile dispersal buffer).
Any one of these represents a population. Together, they represent a metapopulation.

14. Metapopulation Viability Analysis
Bradley Stith et al. (1999) evaluated individual population extinction vulnerability.
Identified 42 metapopulations.
Of the 42 identified , 21 metapopulations were extinction-prone (less than 10 groups).
Modeled 21 major (key) metapopulations.
Evaluated 2 scenarios (assuming fully restored habitat).
No acquisition
Additional habitat acquisition
quasi-extinction (less than 10 groups in 60 years)

15. Recent Genetic Research
A assessment on the genetic structure described 10 major genetic units throughout their extant range (Aurelie Coulon et al. 2008).
The level of genetic differentiation among the 10 genetic units is substantial.

16. Recent Genetic Research
Genetic units are congruent with the metapopulations previously described by Stith, which were based on dispersal behavior.

17. Current Population Numbers of Genetic Units 2009/2010

18. Remaining Florida Scrub-Jay Habitat

19. Southwest Florida Counties
2017
Hillsborough 1 (3)
Manatee (127)
Sarasota (31)
Charlotte (33)
Lee (3)
62 (197)
* Number of Territories (Individuals per Territory)

20. Hillsborough County Location 1992/1993 2010 2016 2017
Golden Aster Scrub 2
1 (5)
1 (3)
Little Manatee S.P. 1
2 (4)
1 (1)

21. Manatee County Location 1992/1993 2014 2017 Duette Preserve 5 (19)
16 (44)
22 (69)
Mosaic Wellfield
1 (4)
7 (20)
6 (23)
South Fork
2 (7)
2 (6)
Moody Branch
5 (16)
3 (15)
Edward Chance
2 (10)
5 (14)

22. Sarasota County Location 1992/1993 2010 2017 Buchan Airport 1 1 (2)
Casperson Beach
3 (4)
2 (4)
Deer Prairie Creek
Lemon Bay 3
6 (16)
2 (5)
Myakka State Park 4
2 (6)
North Schewe 2
Oscar Scherer 19
16(41)
5 (16)
Service Club Park
Shamrock Park 5
3 (8)

23. Charlotte County Location 1992/1993 2010 2016 2017 Amberjack Park 4
1 (2)
Charlotte Harbor 12
2 (6)
2 (7) ?
Prairie/Shell Creek 1
8 (23)
8 (27)
10 (33)

24. Lee County Location 1992/1993 2010 2015 2016 2017 Alva Scrub 1 2 (5)
1 (1)
Hickey Creek 3
3 (7)
4 (11)
2 (6)
1 (3)

25. Questions?