Tuesday, March 07, 2006

Potential Ivory-billed Woodpecker habitat, State-by-State

A few weeks ago I stayed up late many nights going through Terraserver rather exhaustively through most of the "historical range" of the Ivorybill looking for promising bottomlands. I simply looked for large, mostly contiguous tracts of bottomlands that appeared to have a good number of larger, more widely-spaced trees giving the canopy a "coarse texture." There is absolutely no ground truth (as they say in the remote sensing biz) to most of this; consider it a first-generation survey. I think most people will be surprised at how much of this habitat actually exists, especially on the Atlantic slope. I'd especially be interested in the impressions of people who actually know these areas first-hand, on the ground, as well as pointing out areas I may have overlooked.

Apologies in advance to our northern fellows, but I arbitrarily cut off my survey at the northern borders of Arkansas, Tennessee, Georgia, and South Carolina. That does not reflect an opinion on the habitat up there, I just needed to draw a line somewhere so I could get some sleep!

Results are given in the following postings. Everything is listed west-to-east:

South Carolina




Very rough (and generous) totals of the potential habitat for each state (in square miles). These are just eyeballed from the maps, please do not get me in trouble by citing them as actual firm numbers!

TX: 500
AR: 1500
LA: 2000
TN: 300
MS: 700
AL: 500
FL: 2500
GA: 1000
SC: 1500

All states pooled: about 10,000 square miles

General areas that have 300 square miles or more of habitat that is interconnected or at least close together:

Ouachita-Saline (1000 sq. miles)
Big Cypress (800)
Atchafalaya (700)
Winyah Bay basin (700)
Appalachee Bay - Suwannee (600)
Big Woods (500)
Mobile-Black Warrior-Alabama (500)
Altamaha basin (500)
Pearl (400)
Congaree-Santee (400)
Appalachicola (300)

A couple of interesting things... Most (though not quite all) of the primo-suspected Ivorybill areas are on this list. One might infer from this that it takes an area including about 300 square miles of fairly continuous swampland to support the species. This would include a lot of secondary habitat. This would not mean that it takes this much for an individual bird; but it might imply that it takes this much to support the species so it can persist year-to-year in the area. Very speculative, I am the first to admit. Again please do not get me in trouble by citing this as though it were "Fact from an Expert!"

Also rather important -- nearly half of these areas have received little if any attention. Two of the top four may have never been "searched" at all.

South Carolina


I think is the most under-appreciated state for Ivorybill possibilities. Only the Congaree gets much attention. In fact the SC coastal plain hosts a vast network of well-interconnected swamps, and I believe it belongs high in the list of states with potential.

From west to east...

1. Savannah River below Beech Island to highway 17. More continuous and more extensive than on the Georgia side.

2. Coosawhatchie river from Hampton county to above I-95. Fairly small and narrow.

3. Salkehatchie river from Barnwell county to highway 17, plus the Little Salkehatchie in Colleton county.

THE "ACE" (Ashley-Cooper-Edisto) BASIN:

4. South Fork Edisto River from Kitching Mill to highay 301. Moderately wide but not well connected.

5. Four Hole Swamp from highway 176 to the Edisto confuence, plus a narrower stretch south to ACE Basin NWR. Four Hole is a beautifulswamp.

6. Cooper river below lake Moultrie to I-526. Short and fairly narrow, includes Cypress Gardens.


7. Francis Marion National Forest, especially the Wambaw and Little Wambaw Swamps and Hellhole Bay. Some of this is designated Wilderness area. The "I'on" [Iron] swamp doesn't look especially Ivorybill-ish.

8. Congaree Swamp and upper Santee River above Lake Marion. Very broad and mature.

9. Wateree River below I-20 to Congaree. Another big fat gorgeous swamp that is continuous with the Congaree.

10. Santee River below lake Marion to highway 17. Very broad especially in the upper portions. At the lower end a complex of arcuate swamps including White Oak Bay provides a corridor between the Santee Delta and Winyah Bay.

11. Large complex of Carolina Bays in the Foreston-Greeleyville area that could provide a corridor connecting the Santee and Black River drainages.

A massive and largely overlooked network of swamps extending into southern North Carolina. Gaps between the major swamps are easily bridged by small forest and swamp corridors and extensive flatwoods in the lower coastal plain and along the Waccamaw neck. For instance, when we lived in Georgetown on the shore of Winyah Bay (in an old residential neighborhood within sight of downtown, the steel mill, and the paper mill), we had a black bear roam through the neighborhood. There have also been "large cat" reports in the area.

12. Pocatiligo river below Sumter to Black river confluence.

13. Black river from headwaters to near Oatland. Quite broad in Clarendon and Williamsburg counties, potentially connected to Santee basin through area #11 above.

14. Little Lynches river below Kershaw to Lynches confluence, continuing down the Lynches to the Pee Dee.

15. Pee Dee river from just above the NC border to Great Pee Dee, continuing downstream to highway 701 where it merged with the Waccamaw swamps. Broad; downright huge from Society Hill to highway 501.

16. Little Pee Dee river from its headwaters region in NC to Great Pee Dee confluence. Also very broad.

17. Waccamaw river from headwater swamps in the Lake Waccamaw region of NC to the Great Pee Dee confluence.


Another state that often gets left off the lists.

A general note about river swamps in Georgia and the Carolinas... as the rivers come off the piedmont into the coastal plain, they slow down suddenly at the fall line and deposit great loads of sediment. This typically builds large swamps for 20-40 miles below the fall line. Farther downstream the floodplains often narrow across the middle coastal plain, then broaden again in the very flat lower coastal plain. So atlantic slope river swamps often have a stretched-out hourglass shape -- fat at the top and bottom, narrower in the middle.

Most of the gulf coastal plain in Georgia is relatively hilly uplands, so the swamps are not as well developed over much of it. But there are some, including one famous one.

1. Flint River from highway 96 to Lake Blackshear. A moderately well developed fall-line swamp.

2. Alapaha river from highway 82 to Mayday, fairly short and narrow.

3. The Okefenokee Swamp -- a difficult case. On the one hand, most of it doesn't really look like the best habitat, consisting of dense stands of relatively young trees (mostly cypress) and virtually no old growth. On the other hand, it is huge, managed as wilderness , and the forests are getting more mature every decade. Plus the Suwanee provides a corridor connecting up with large areas in Florida. Some of the more promising areas are along and north of the Suwannee river above the Suwannee sill and trending towards Floyd Island, and in the southern parts south of Blackjack Island.

4. Suwanee River below the Sill on in to Florida

Some nice swamps here

5. Satilla River below Waycross to below highway 82.

The Altamaha system -- a large and virtually unbroken collection of river swamps, made of several segments:

6. Ocmulgee river below Macon. The fall line swamp here has been developed in some spots for mining and industry but still is fairly extensive, and good bottomlands continue downstream

7. Oconee river below Milledgeville. Just below the fall line it is very large and intact, forming the "Great Oconee Swamp" for about 40 miles.

8. Altamaha River -- entire length from the Ocmulgee/Oconee confluence to just above I-95. Well developed, wide, and with several stands of old growth.

9. Ohoopee River below Ohoopee to the Altamaha.

Also on the Atlantic slope:

10. Ogeechee River from Grange to above I-95, especially the fall-line swamp in Washington and Jefferson counties, and another wide stretch in Effingham and Bulloch counties; plus lower Black Creek in Bulloch and Bryan counties

11. Savannah River below Augusta to near Clyo. Extensive clay mining in the fall line swamp, and most of the best floodplain swamps are on the South Carolina side.


Just the major areas; there are hundreds of small batches of nice bottomlands


Pensacola Bay tributaries --

1. Escambia River (entire length) quite nice

2. Yellow River (entire length) plus Titi Creek and lower Shoal River

3. East Bay River

Others --

4. Chocktawhatchee River (entire length) plus Pine Log

5. Appalachicola River, entire length but especially below Bristol; extensive swamps in lower delta.

6. Ochlockonee below Lake Talquin, plus Bradwell Bay and other flatwoods swamps around lower portion


7. Extensive coastal flatwoods from in Taylor, Dixie, Levy, and Citrus counties. Large continuous forest areas from just behind the saltwater line for 5-10 miles inland, plus a large patch in east-central Levy county inland of highway 19.

8. Suwannee River (entire length) plus lowermost Withlacoochee River and Santa Fe River below I-75, contiguous with the coastal forest

9. Withlacoochee River (not the same one as #8) along the Citrus - Sumter county line

10. Upper Hillsborough - Withlacoochee area in Hillsborough, Pasco, and Polk counties.

11. Peace River from Bowling Green to Charlotte Harbor

SOUTH FLORIDA (below Lake Okeechobee):

12. Corkscrew Swamp. Beautiful and famous but more fragmented than I expected.

13. Big Cypress area. The largest patch in Florida. Especially north of Highway 41, including the Seminole and Miccosukee Reservations and Fakahatchee Strand.

14. Northeastern Hendry county, a lot of interesting looking areas, mixed forest and open land, hard to interpret from the air -- Devil's garden, Wild Cow Island, places around there.

15. Loxahatchee NWR (though it seems pretty unlikely they'd have been overlooked here)

This is some awfully heavily settled country for much to have been overlooked, but there is interesting habitat:

16. Upper St. Johns on Orange/Brevard county line.

17. Spruce Creek Swamp, southern Volusia county

18. Middle St. Johns from estreme eastern Lake county to areas surrounding Lake George and Crescent Lake. Quite a lot of nice swampland but fairly well-populated with those hairless ape creatures too.

19. Ocklawaha River in central Marion county.

And finally...

20. Lower Nassau River along the Nassau/Duval county line (including Timucuan Preserve). Fairly small and isolated.



Though it almost never gets mentioned, there is at least one big beautiful area here that definitely needs attention. I've divided it in to three pieces, but all three are contiguous:

1. Black Warrior River below Tuscaloosa county to its confluence with the Alabama. Extensive and rather wide in places, particularly along the Greene/Hale county line, and where Choctaw, Marengo, and Clarke counties all come together. The lowermost portion near the confluence (southern Washington and Clarke counties) is quite broad and impressive.

2. Alabama River below Miller's Ferry lock and dam to the Black Warrior confluence. Narrower except at the lowermost reach, but continuous and long.

3. Upper Mobile river from the confluence to above I-65. A very broad swamp which in combination with the lower parts of the two areas above forms an area of continuous bottomland forest up to 15 miles wide in extreme southern Clarke, southeastern Washington, extreme northeastern Mobile, northwestern Baldwin, and extreme southwestern Monroe counties.

Farther east in Alabama are three areas that are the upstream tips of swamps whose major portions are in Florida:

4. Conecuh River below Brewton

5. Yellow River below highway 65

6. Chocktawhatchee River below Wicksburg


Some interesting areas that I've heard little about.

1. Mississippi mainstem from Bolivar to Tunica counties -- many smallish forest fragments, more than in other states.

2. Delta National Forest and Panther Swamp NWR -- some of the largest forest patches in the Mississippi Alluvial corridor.

3. Big Black River, Mathiston to I-20 -- narrow but very long.

4. Mississippi mainstem and lower Buffalo River in southern Adams and northwestern Wilkinson counties -- rather extensive forests. Worth noting that this along with LA areas #9 and #10 forms a pretty good size area of almost interconnected forest.

5. Pearl River below Columbia to highway 90 (also in LA) -- primo area, very extensive, goes far beyond the portions that have been intensively explored by birders recently. Reports of possibly two Ivorybills from this area in the past few weeks.

6. Leaf and Pascagoula Rivers from McClain to I-10 -- another large area.



There are no historical records for Tennessee, though this is generally thought to reflect mostly how rough and tumble and poorly-collected western Tennessee was during the 19th Century. It is believed that Ivorybills must have surely occurred in the Mississippi bottomlands, as they were recorded from adjacent states.

In spite of being "the greenest state in the Land of the Free," present-day TN has few extensive remnants of mature coastal plain bottomland forests. I've only picked out one as looking like potential ivorybill habitat:

1. Hatchie River from near Hebron to about highway 51, plus a narrow strip continuing downstream connecting to some forest patches aong the Mississippi -- the "Hatchie Bottoms." Actually a quite nice, wide, continuous, and mature band of forest, its biggest strike is its isolation from other good habitat.

There are other smaller bottomland areas along the South, Middle, and North Forks of the Forked Deer River above Dyersburg and below highway 45. I didn't see any large areas around Reelfoot Lake, though if you combined the small forest fragments there with the larger upland bluff forest north of Dyersburg, and the North Fork Forked Deer River swwamps to the east, collectively it is a moderately large patch of forest. Once again, the Mississippi mainstem forests are highly fragmented.


One of the best known and most discussed states.

Mostly well known places.

1. Sabine -- decribed under TX

2. Upper Atchafalaya floodway west of the main channel, below highway 190 to Lake Fausse Pointe, in a strip up to five miles wide. Right along the main channel does not look as promising.

3. Upper Atchafalaya floodway east of the main channel though Iberville Parish, in a wide (up to ten miles) band.

4. Lower Atchafalaya floodway in much of Lower St. Martin Parish, extreme southern Assumption Parish, and adjacent Terrebonne Parish. Another fairly large area. Also a nearly contiguous area of coastal swamp forest in south-central St. Mary Parish.

5. Lac des Allemands basin, west of the Lake, south of the Mississippi and north of Bayou la Fourche. I've not heard much about this area; comments?

Also some smaller, narrow areas along Calcasieu, Bundick, Bayou Nespique, and Bayou Queue de Tortue.

Less has been said about this region since the 1940s.

6. Ouachita above Bastrop -- connects with the large swamp in AR.

7. Bayou la Fourche in Ouachita and Richland Parishes, plus Bayou Galion below the railroad, and lower Boueff River below Buckner. A fairly large but somewhat discontinuous area.

8. Tensas NWR (both units), the general vicinity of the former Singer Tract.

9. Black River below Acme -- a fairly large but fragmented area.


10. Mississippi mainstem floodplain in western West Feliciana parish and parts of extreme eastern Pointe Coupee parish. Not a place I remember having heard anything about.

11. Maurepas basin, primarily between the lake and I-10, and up the Antes river to near Port Vincent.

12. Pearl River along the MS border and lowermost Bogue Chitto to below I-10. Well known, multiple recent Ivorybill reports.


Many surprises here.


This is a massive area of well-interconnected bottomland forests that rivals the Big Woods in size, and about which I have heard nothing. The swamps are extensive, wide, and seem to contain significant areas of mature-looking forests. It really looks like the Big Woods all over again but with less public land. I would dearly love to hear comment from anyone who has actually been here! Specific areas, all of which are interconnected, producing one huge swamp:

1. Little River from below I-30 to Ouachita confluence.

2. Ouachita River from Dallas County south to LA border -- huge area.

3. Moro River over nearly its entire length, especially below Ivan.

4. Saline River from around Highway 9 (above I-30) to Ouachita confluence -- another huge area.

5. Hurricane Creek from below Sardis to Saline confluence -- relatively narrow but continuous.

6. Big Creek (Cleveland County) from Saline upstream 10 or 20 miles.

7. Hudgin Creek below about highway 114 to Saline confluence -- also relatively narrow.


Now well-known, but larger than most are aware. The following areas are all contiguous:

8. Lowermost Arkansas River below highway 165 to the Mississippi. Above this the forest is heavily fragmented. Rather extensive forests continue on the Mississippi floodplain south to Lake Whittington.

9. White River from below highway 64 (White County) to the Arkansas confluence. Most extensive from the Cache River south, but well developed north of there too. Very wide in the White River NWR area.

10. Cache River from Grays to White confluence. Most extensive in Dagmar WMA area.

11. Bayou de View from central Woodruff County to Cache confluence. Relatively narrow above Dagmar but continues 10-15 miles above the highway 17 bridge.


Not interconnected with each other or the two big swamps described above --

12. Black River in Clay County, continuing northwards into Missouri ten miles or more. Rather large area, but isolated.

13. St. Francis River from near Kennett MO to near Marked Tree AR (Poinsett County). Narrow but well-developed, incuded 20 miles or more along the AR/MO border.

Smaller isolated patches are on the Little River in Mississippi County, and in the St. Francis National Forest. The Mississippi mainstem floodplain forests are highly fragmented.


I found no real surprises here.

1. Trinity River below Lake Livingston Liberty, possibly also a short ways upstream from the lake.

2. Neches River from below Rockland to above Beaumont; this includes Big Thicket.

3. Sabine River from about TX highway 63/LA highway 8 to about I-10; below Toledo Bend Reservoir and above Orange TX. This is along the TX/LA border.

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