Archive for May, 2022

Vacation 2022 Part 2–The Harris Neck National Wildlife Refuge

May 25, 2022

During World War II the U.S. government bought the land that currently makes up The Harris Neck National Wildlife Refuge. Before the Civil War most of this land belonged to a single wealthy plantation-owner, but in 1865 he deeded the land to one of his slaves. The land was later sold in parcels to white and black families who primarily worked in the seafood industry. An airfield was built on one of the parcels of this land during 1929 to serve as an emergency landing strip for flights between Jacksonville, Florida and Richmond, Virginia. The U.S. Army Air Force decided to purchase the airfield and all of the surrounding land during 1942, so the airfield could be used for aircraft that hunted for German submarines lurking off the coast. The U.S. government paid white landowners $37.21 per acre, while black owners were paid $26.90 per acre. I’m against reparations for slavery because it is too late. The time for slavery reparations was 100 years ago, but the victims of slavery and their immediate descendants are long gone. It also seems ridiculous to make modern taxpayers pay for the sins of some people’s great-great-great-great-grandfathers. However, I am in favor of reparations for African Americans who suffered discrimination by the federal government since the World War II era. The above-mentioned land purchase is one example. Many WWII era black veterans were denied GI benefits given to their white counterparts. The Agriculture Department routinely would not give loans to black farmers. Families that can show the federal government discriminated against them since the WWII era should be eligible for reparations. Many of these families and their immediate descendants are still alive.

Harris Neck Wildlife Refuge is located near Brunswick, Georgia, a coastal industrial town. I saw 14 species of birds here in less than an hour. (We didn’t stay long because the burning sun punished us, while biting horse flies dive-bombed our heads.) As soon as I parked my car, I spotted rare male and female painted buntings feeding at a bird feeder placed near the entrance. This alone made this side trip on the way home from Jekyll Island worth the time. I almost took a perfect photo of the colorful male, but it flew away as soon as my camera focused. I didn’t want to keep harassing the shy bird and left satisfied with my partially obscured photo.

Spanish moss-draped live oaks dominate the drier areas of The Harris Neck National Wildlife Refuge.
I saw these rare painted buntings as soon as I pulled into the parking lot. The male is the more colorful one. I almost took a photo of its entire body, but it flew away as soon as I had it in focus. I didn’t want to continuously harass it.

We walked to a couple of ponds, past the “don’t feed the alligator” signs, and saw great egrets, snowy egrets, cormorants, anhinga, and endangered wood storks. Who is stupid enough to feed an alligator?

I think this is an anhinga and not a cormorant because of the neck coloration.
This is a double-crested cormorant.
Endangered wood stork in flight.
Endangered wood storks.

This refuge is a mecca for ducks, geese, and bald eagles during winter, and during summer it serves as a rookery for egrets, herons, and storks. I was excited to realize when I got home that I’d taken a photo of a black-crowned night heron. I took the photo from a distance into the shade and wrongly assumed it was just another great blue heron. I have taken many photos of great blue herons. I can now add this species along with the painted bunting to my lifetime bird checklist. I had never seen either species before. In addition I saw red-headed woodpecker, red-bellied woodpecker, mourning dove, cardinal, tufted titmouse, black vulture, and a catbird.

Black-crowned night heron. This was the first time I had ever seen this species, and I didn’t realize I had gotten it on camera. I took this shot from a distance and assumed it was just another great blue heron.

Vacation 2022 Part 1–Jekyll Island

May 20, 2022

We were pleased with our room in the Days Inn at Jekyll Island. Many hotels claim to be handicapped friendly, but it seems as if they pay perfunctory attention to the needs of disabled people. However, this hotel really had excellent handicapped facilities, making my wife happy, thus reducing my stress, so I could enjoy the beach.

Driftwood Beach

An interesting active geological action is currently taking place on Jekyll Island. Engineers dredge the river outlet north of the island, and along with natural currents, this is causing the north end of the island to rapidly erode. The ocean is inundating a maritime forest here, killing the live oaks and cedar trees where they stand. This landscape is beautiful and different. Jekyll Island is not shrinking away. Longshore currents carry the eroded sediment from the north end of the island to the south end, and this end of the island is expanding in the form of large sand dunes.

The ocean is inundating the northern end of Jekyll Island, killing the maritime forest that stood here for centuries.
One can see how extensive a live oak’s root system is.
Bye bye forest, hello ocean.
Sediment from the north end of the island is carried by longshore currents to the south end of the island where it forms large sand dunes.

Sharktooth Beach

I’d rename this broken shell beach. Although I’m sure people find shark teeth here, they are greatly outnumbered by broken seashells. The beach appears to be composed of modern shells mixed with black-colored fossil specimens. It took us about 15-20 minutes to walk from the road to this beach located on Jekyll Creek between the island and the mainland. Many cedar trees covered in grapevines grew alongside the trail, and a salt marsh was also adjacent.

Sharktooth beach. We didn’t find any definitive shark’s teeth here.
Oyster shell, sea drill, and some other broken shells I found on Sharktooth Beach. The darker ones may be fossils.

The Sea Turtle Center

Veterinarians treat injured sea turtles here. Most are injured by human activities. It is worth the visit, but I felt sad the only opportunity to see these poor creatures is when they get hurt.

Loggerhead sea turtle being cared for at the Sea Turtle Center on Jekyll Island.
Juvenile loggerhead sea turtle.
Sinkey Boone, a shrimp trawler captain, invented the sea turtle excluder which are now required equipment on all shrimp trawlers. They let in shrimp but prevent turtles from getting caught in the nets and drowned. Sinkey seems like a bad name for a boat captain.
Diamondback terrapin juveniles. The Sea Turtle Center also cares for this species and injured box turtles as well.

Birds on Jekyll Island

I saw 19 species of birds on Jekyll Island plus gray squirrels, and the tracks of rabbit, deer, and raccoon on the beach.

Female boat-tailed grackle. This species is by far the most common songbird on the island. Males are larger and pure black.
Piping plover. This species spends summers in high northern latitudes. It still has a long way to go.
I think these are semi-palmated sandpipers.
I cannot identify what species of sandpiper this is. Closest match I can find is a sanderling. Somebody help.
This was part of a huge flock of brown pelicans.
Even Bugs Bunny likes to go to the beach. These are rabbit tracks.

My bird checklist for Jekyll Island includes boat-tailed grackle, red-winged blackbird, mourning dove, bluebird, cardinal, tufted titmouse, green heron, snowy egret, laughing gull, ringed gull, piping plover, semi-palmated sandpiper (I think), sanderling (I think), immature white ibis, common crow, fish crow, black vulture, black skimmer, and brown pelican. I also saw gray squirrels, a road-killed black racer, and the tracks of rabbit, raccoon, and deer.

2 Miocene-Aged Fossil Sites in Florida

May 11, 2022

The University of Florida Museum list 9 Miocene-aged fossil sites in Florida. By contrast there are no significant Miocene-aged fossil sites in Georgia. However, animals that lived in Florida also occurred in Georgia because the same habitats–subtropical forests and woodlands–prevailed over most of North America during the Miocene era, a period of stable warm climate. The Miocene lasted a long time from 25 million years BP-5 million years BP, but this division of time is an artificial human construct. Species that lived during the early Miocene were completely different, though often ancestral, to those that lived in the later Miocene. Therefore, I chose to examine the lists of Miocene species that occurred at 2 different sites with fossils separated in age by over 10 million years. Both sites are located northwest of Gainesville, Florida and are about an hour drive from the Georgia border. Certainly, these species lived in Georgia as well.

Fossils from the Thomas Farm site are estimated to be 18 million years old or early Miocene. The site was discovered in 1931 when Raeford Thomas dug a well into an ancient sinkhole. Clarence Simpson of the Florida Geological Society looked through the dirt dug up from the well-drilling and was the first to catalogue fossils at the site. The site has been studied off and on ever since, and scientists consider it the best North American Miocene-aged site east of the Mississippi. Paleontologists list 1 species of fish, 12 species of amphibians, 23 species of reptiles, over 27 species of birds, and 40 species of mammals from the fossil evidence left here. Most notable among the reptile fossils are an extinct boa constrictor (Boa barbouri), and an extinct alligator (Alligator olseni). Boa constrictors are now restricted to southwestern North America south to South America, but they were widespread across North America during the warmer Miocene. Olsen’s alligator was somewhat smaller than modern alligators. None of the bird fossils found here have been diagnosed to the species or even genus level. Scientists are unfamiliar with birds from this era, and they can only diagnose the specimens down to the family level. The most common large vertebrate fossils found here are from 3-toed horses and rhinos both of which dominate Miocene fossil assemblages. A common species of horse of this era was the 60-pound Archaeohippus blackbergi. Many of the specimens suggest high mortality caused by intraspecific fights between males who sported long canines. Thomas Farm is the only site where bones of an extinct camel known as Floridatriculus dolochiantereus have been found. Extinct species of pronghorns also left fossil evidence in the sinkhole. The top predator was White’s bear-dog (Amphicyon whitei). It was related to the common ancestor of bears and dogs, and it grew to the size of a grizzly bear.

This 60 pound 3-toed horse was a common species in early Miocene forests. 3-toed horses occupied an ecological niche filled by white-tailed deer today.
Bear-dogs were a top predator during the early Miocene. White’s bear-dog grew to the size of a grizzly. They were related to the common ancestors of bears and dogs.
Extinct species of pronghorns ranged throughout southeastern North America during the Miocene. Today, there is just 1 species restricted to short grass prairies in some western states.

Farmers plowing a peanut field discovered Miocene-aged fossils at the Tyner Farm site. This site was excavated between 2001-2005, and fossils from this site are estimated to be 7.5 million years old. Paleontologists list 4 species of amphibians, 6 species of reptiles including 2 kinds of giant tortoise and the remains of the modern species of alligator (A. mississippiensis), and 25 species of mammals. The site yields the oldest dated fossil remains of a tree squirrel in North America. Like the older dated Thomas Farm site, the fossil assemblage is dominated by 3-toed horses and rhinos, though they are different species than those found at the older site. Bones of 4 species of horse, 2 species of rhino, 2 species of pronghorn, 3 species of camels, 1 species of tapir, and 1 species of peccary were found here. 1 species of camel is particularly remarkable–Aepycamelos major. It was 13 feet tall, not counting its 6-foot-long neck, and it weighed over a ton. This species is a good example of convergent evolution. Like giraffes, it evolved great height and a long neck to feed upon leaves and twigs other vertebrate herbivores couldn’t reach, and scientists refer to them as giraffe-camels. Top predators included the Borophagine or bone-eating dogs, and the saber-toothed cat (Machaerodes catcopsis). The latter species was likely ancestral to the more famous late Pleistocene species of saber-tooth cats.

This is the hippo-like rhino. Along with 3-toed horses, rhinos were the most common large herbivores during the late Miocene. Rhinos became extinct in North America at the end of the Miocene when Ice Ages began.
The amazing giraffe-camels are a great example of convergent evolution. Despite not being closely related to giraffes, they evolved long necks to help them reach the leaves at the top of trees they could eat.

Pleistocene North America is often compared to modern day Africa in its faunal diversity. However, as I’ve noted in a previous blog entry (See: https://markgelbart.wordpress.com/2013/12/09/the-faunal-diversity-of-pleistocene-north-america-was-less-than-that-of-modern-day-africa/ ), modern Africa far exceeds Pleistocene North America in number of genera and species. Miocene North America makes a better comparison in diversity because a far greater number of animal species occurred on the continent during this era. Ice Ages began occurring at the beginning of the Pliocene about 5 million years ago. Seasonal climates including sub-freezing weather severely reduced the number of species that could live in North America.

Reference:

https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/sites/

A Lake and 2 Rivers in Florida that Vanish

May 4, 2022

The Native-American name for Lake Jackson, located near Tallahassee, Florida, is Lake Okeeheebee, meaning disappearing waters. Local authorities should have kept the original name because there is another Lake Jackson in central Florida, and there is also a Lake Jackson in nearby Georgia. The existence of multiple Lake Jacksons in this region made researching this blog article confusing. I wonder what Native-Americans thought the reason was for the periodic draining of this lake. They probably invented some kind of mythical story. Modern geologists know the cause for the periodic disappearance of this lake. The lake sits on karst terrain where sandy soils prevail. Karst terrain consists of unevenly eroding limestone. Slightly acidic rain causes bedrock to erode, resulting in many underground caverns that often collapse into sinkholes. There are 2 sinkholes underneath Lake Jackson–the Porthole Sink and the Lime Sink. During dry spells when the water table falls, water from Lake Jackson drains into these sinkholes, just like water draining from a bathtub. Plant debris and mud will temporarily block the sinkholes, but eventually most of the lake will drain with the exception of small pools here and there where fish populations survive. The permeable sandy soils allow water to refill the lake following periods of higher rainfall that cause the local water table to rise.

Map and location of Lake Jackson in north Florida. From Wikipedia.
Lake Jackson when it is full of water.
Aerial photograph of Lake Jackson after its water vanishes. Lake Jackson is surrounded by wet prairie. From the Tallahassee Democrat by Daniel Martinko.

Lake Jackson is 6.2 square miles and averages 6 feet deep when it is full of water, though it is as much as 28 feet deep over the sinkholes. The lake has drained 14 times over the past 200 years, and it is currently in a drained stage. Surprisingly, periodic drainages are good for fishing. The draining reduces populations of the non-native plant hydrilla, and the re-filling stirs up nutrients, increasing food for rebounding fish numbers. Fishermen claim the fishing for largemouth bass, crappie, bluegill and redear sunfish, and bullhead catfish is excellent. The latter species is especially well-adapted for surviving in small pools during drainage phases. Though not mentioned on the internet, I’m sure bowfin, gar, and non-native tilapia thrive as well. Birdwatchers report the presence of herons, egrets, limpkins, eagles, ospreys, ducks, geese, fish crows, and least terns. It’s good habitat for alligators, turtles, and frogs too.

The karst terrain makes it difficult for rivers to flow in this region, and there are 2 rivers that vanish here. The Alapaha River, a tributary of the Suwannee River, simply disappears into the ground, flowing right into a sinkhole, and it emerges miles away. The Santa Fe River also disappears into a sinkhole, also to emerge miles away. Both become subterranean during part of their course. A river flowing into the ground is known as a swallet.

Photo of the Alapaha River where it vanishes into the ground. It re-emerges miles away.
Image of where the Santa Fe River vanishes. From a youtube video by Adlai, JN.

Reference:

Bryan, J., Scott, T., Means, Guy

Roadside Geology of Florida

Mountain Press Publishing Company 2008