Archive for the ‘Ornithology’ Category

John J. Audubon’s Trip Down the Ohio and Mississippi Rivers During 1820/1821

April 20, 2022

It’s hard to imagine how rich in wildlife the woods, fields, and streams of North America used to be. This is why I enjoy reading the journals of early explorers and settlers who described these forlorn scenes of nature. They saw more wildlife in a day than most modern people see in a year both in numbers and diversity. Audubon kept a journal of his trip down the Ohio and Mississippi Rivers, a journey that lasted from October 12, 1820 to January 7, 1821, and it is an extensive account, documenting the former abundance of wildlife in the region. Audubon had suffered business reversals when his once prosperous store went bankrupt, and he decided to travel to New Orleans where he could make money by drawing portraits of rich people and by giving art lessons. He was also working on an illustrated book of birds he hoped to sell in England. He left his family in Cincinnati, and he expected to be gone for 7 months. He traveled on a flat boat with an 18 year old young man, a boat captain, and a hunting dog named Dash that he alternatively referred to as “the bitch” or “the slut.”

J.J. Audubon and his dog. Although his name is attached to a modern conservation society, he killed as many birds as he could shoot.

Audubon and his young companion stopped to hunt every morning. Audubon carried a primitive shotgun known then as a fowling piece, and he shot just about every animal he saw. Unlike the organization that today uses his name, Audubon was not at all concerned about conservation. In his later years he did lament the reduction in game populations, but then he’d kill as many birds as he could shoot. A typical day of his journey was the first when he and his companion killed 30 “partridges” (probably quail), 27 squirrels, 1 woodcock, 1 barn owl, and 1 turkey vulture. After the morning hunt, he would draw 1 of the dead birds as the boat drifted downstream. Then he would pluck and clean the bird and throw it on the embers of the fire for his supper. Grebes were fishy, but he pronounced red-breasted thrushes (robins) to be fat and delicious. Birds that are now extinct were common during the early 19th century. Audubon often saw ivory-billed woodpeckers, and he stated they were more abundant along some parts of the river than pileated woodpeckers and flickers. He once shot 10 Carolina parakeets and fed them to his dog to see if they were poisonous. This seems strange, but Audubon often engaged in sadistic “scientific” experiments. He wrongly came to the conclusion parakeets were not poisonous when his dog didn’t get sick. He didn’t know the flesh of parakeets only became poisonous after they ate certain species of toxic plants. Audubon also wrongly thought immature bald eagles were a different species of eagle, and in another sadistic experiment he once nailed the foot of an eagle to the bottom of the boat, so he could draw it while it was alive. He claimed bald eagles were a new species and named it the bird of Washington after the first President.

Alexander’s painting of a bald eagle (top) and Audubon’s painting of a bald eagle (below). Some think Audubon simply plagiarized Alexander’s painting and falsely claimed his was based on a freshly killed eagle.

Species of birds still extant today were much more abundant and widespread during Audubon’s time. He saw a flock of 100 white pelicans on a sandbar in the Ohio River. White pelicans are not often seen on the Ohio River today. He also saw enormous flocks of thousands of ducks, geese, and blackbirds. Swans, herons, and sandhill cranes were a common sight. In addition to daily hunting, Audubon always set a line out for fish. On 1 occasion he caught a 64-pound catfish, likely a blue catfish–a new species for him. I’m sure the offal from all the birds he killed made excellent catfish bait. Big flocks of sea gulls followed the boat and fed upon the dead bird and fish parts he threw overboard. Once, his hunting led to fish and bird…he shot a merganser with a 9-inch-long sucker fish in its throat. Nearly extinct habitats were abundant then as well. They floated down parts of the river bordered by many miles of bamboo cane tangled with smilax vines. Canebrakes are very rare today.

Audubon saw a flock of 100 white pelicans on a sandbar in the Ohio River. According to range maps, this species no longer regularly occurs on the Ohio River.

Audubon reached New Orleans on January 7th. Gulls, fish crows, and robins were the most common winter birds here. Later in the season, the robins left, but tree swallows arrived to become 1 of the most common birds around the city. On his 2nd day in New Orleans, someone picked his pocket, but he was almost broke anyway. He made his living painting people’s portraits and giving art lessons. A notable incident while he was living in New Orleans was when he witnessed local hunters destroy a flock of 144,000 migrating golden plovers. Eventually, Audubon got a job tutoring the daughter of a rich plantation owner. (Audubon was unapologetically pro-slavery.) He taught her art, dancing, and math for $60 a month plus room and board. The plantation was located on Bayou Sara, and Audubon hunted daily in a nearby cypress swamp where he frequently saw prothonotary warblers, yellow-throated warblers, water thrushes, Mississippi kites, ivory-billed woodpeckers, and alligators. The women in the household where he tutored gradually cooled to him, and he quit. I wonder if they were expecting more romance from the married tutor. The lady of the house didn’t want to pay him, but the man did anyway. The private journal ends when Audubon returns to New Orleans, following his tutoring gig. Years later, Audubon did become successful selling his illustrated books about North American birds and mammals.

References:

Audubon, J.J.

Audubon: Writings and Drawings

Literary Classics 1999

Halley, M.

“Audubon’s Bird of Washington: Unravelling the Fraud that Launched The Birds of America

Bulletin of the British Ornithologists Club 110-141 2020

Pleistocene Caracaras

April 6, 2022

The pasturelands interspersed with woodlots that cover much of rural south Florida today likely resemble the coastal oak and pine savannahs of this same region during the Pleistocene. South Florida and the southern Gulf Coast were climatically out of sync with the rest of North America during Ice Ages. When climate phases of dry cold conditions struck the rest of North America, south Florida and the southern Gulf Coast experienced warmer wetter subtropical climates. The Gulf Stream of the present day carries tropically heated water north, keeping climates in the northern latitudes of North America relatively moderate, but during cold climate phases of the Ice Age, it shut down. Instead, this warm water stayed at lower latitudes ironically making climate along the southern Gulf Coast even warmer than present day conditions. This warm climate spurred frequent thunderstorms and hurricanes. Lightning-ignited fires and windstorms destroyed trees and created open savannahs where mammoths, bison, and horses further suppressed the growth of unbroken forests. Trees that survived fire and wind were spaced far apart, and woodlots were restricted to the vicinity of waterholes where the trees were protected by watery fire breaks. This warm savannah habitat occurred from south Florida, Alabama, Mississippi, Louisiana, and Texas all the way to eastern Mexico. Much of this land has been inundated by sea level rise since the end of the last Ice Age. Warm coastal savannahs were ideal habitat for many species of plants and animals including caracaras.

Crested caracara. Photo by Wisniewski.
Crested caracara range map. There is a disjunct population in south Florida. During the Pleistocene this range was continuous with its population in Central and South America. Warm savannah occurred along the Gulf Coast, much of which is now inundated by rising sea levels.

Two species of caracaras inhabited Gulf Coast savannahs during the last Ice age–the crested caracara (Polyborus plancus) and the yellow-headed caracara (Milvago reidei). The former still occurs as a relict population in south Florida. This species lived on dry prairies throughout much of Florida, but that type of habitat has largely been transformed to rural, suburban, and urban landscapes. A recent scientific study in Florida found 103 crested caracara nests, and most of those were on improved pastureland. They seem to prefer pastureland over what remains of their original dry prairie habitat. I think this is a clue they benefit from the presence of megafauna. During the present day this means herds of cattle, but formerly they accompanied now extinct and extirpated megafauna. Caracaras forage on the ground for carrion. There was an abundance of carrion during the Pleistocene. They hunt for insects, reptiles, and small mammals stirred up by grazing herds of megafauna. And along with swallow-tailed kites and other opportunistic birds, they hunt down small animals fleeing wildfires. The widely spaced trees and small woodlots located on the pastures or savannahs are used for nesting.

Study of crested caracara nests in south Florida. Most of their nests are located on cow pastures that resemble Pleistocene habitat. Image from the below reference.
Yellow-headed caracara.
Yellow-headed caracara range map. During the Pleistocene they also occurred in Florida.

Fossil remains of both species were found at the Cutler Hammock site located in Miami, Florida. Yellow-headed caracaras no longer occur in North America, but habitat during some phases of Ice Age climate was so favorable in this region that it attracted both species. The Cutler Hammock site is notable for having yielded many remains of large carnivores including dire wolf, saber-tooth, giant lion, jaguar, and cougar. Their kills helped feed a diverse population of avian scavengers.

Reference:

Morrison Joan

“The Crested Caracara in the Changing Grasslands of Florida”

Click to access 3-17145_p.21115_Mor_FDPC_d.pdf

See also: https://markgelbart.wordpress.com/2013/10/18/two-pleistocene-carnivore-dens-near-miami-florida-part-2/

Cretaceous Age Fossil Feathers Found in Alabama

March 23, 2022

More fossil feathers of Cretaceous Age have been found in the state of Alabama than in any other state. 14 fossil feathers, encased in shale, were found in a lens located in the Eutaw Formation, the site of an ancient shoreline. Shale is basically fossilized mud, and ocean currents rapidly buried the feathers in mud which eventually turned to shale. The fossilized feathers are impressions of the original objects. The Cretaceous Age lasted from 145 million years BP to 66 million years BP, and these feathers probably date to about 80 million years ago. Fossilized feathers have also been found in Kansas, New Jersey, New Mexico, and Alberta; but none of these states or provinces have yielded as many as Alabama.

Fossil feathers found in Alabama. The impressions were made in mud and later fossilized when the mud turned to shale. Photo from the below reference.

The feathers include 2 different sizes. Scientists believe the smaller ones come from extinct species of shorebirds. The larger feathers may be from the tails of either a species of hesperornthid or a dromaeosaur. Hesperornthids were an aquatic fish-eating dinosaur that occupied a niche similar to modern day penguins. They were related to the ancestors of birds, and they lived in lakes, rivers, and oceans. Dromaeosaurs include dozens of families of carnivorous dinosaurs ranging in size from 2 feet long to 20 feet long. Some species hunted in packs, though paleontologists are unsure whether they were organized hunters or disorganized mobs like modern Komodo dragons and crocodilians. Some species had a large retractable claw on their 2nd toe that could inflict devastating damage on their prey or each other. Carnivorous dinosaurs were cannibalistic, and the number of carnivorous predators in ratio to herbivorous prey was higher than in modern day ecosystems. For example today in a pristine environment there may be 1 large predator per 40 deer, but during the Cretaceous there may have been 1 predator per 5 large herbivores. Dromaeosaurids were related to the ancestors of birds, and some species may be directly ancestral to birds. Paleontologists don’t agree with each other about the exact evolutionary relationship between birds and dromaeosaurs. Nevertheless, I catalogued this blog entry under ornithology.

The larger feathers found in the Eutaw Formation may be from an extinct species of hesperornthid, an aquatic dinosaur. Image from Dinopedia.
Alternately, the larger feathers may be from a species of dromaeosaur. There were dozens of families of dromaeosaurs alive during the Cretaceous. Image from UCMP Berkeley.

Scientists looked at these fossil feathers under a microscope and found structures that look similar to the bacteria involved in feather decay. However, these structures also look like melanosomes responsible for the color in feathers. The feathers from the shorebirds were likely gray, brown, or black. Whether these structures are feather-consuming bacteria or melanosomes is yet another point of contention between paleontologists. Fossils are a vague clue compared to a live organism.

Reference:

Knight, T.; S. Bingham, R. Lewis, C. Saurda

“Feathers of the Ingersoll Shale, Eutaw Formation (Upper Cretaceous) Eastern Alabama: The Largest Collection of Feathers from the North American Mesozoic”

Palaios V. 28 N. 51 May/June 2011

What Vultures Eat in Coastal South Carolina

February 17, 2022

A road trip along any highway in Georgia will usually reward birdwatchers with the sight of vultures patrolling the skies above it. They feast upon the carnage caused by vehicles colliding into animals. Without vultures, roads would be littered with rotting corpses, attracting a plague of disease-carrying flies. In India recently, vultures were poisoned, causing a disastrous problem with sanitation. There are 2 species of vultures in southeastern North America–the turkey vulture (Cathartes aura) and the black vulture (Coragyps atratus). Both species nest communally, but the former flies in solitary pursuit of carrion, while the latter scavenges in flocks for dead animals. Though carrion makes up a majority of the diet of turkey vultures, they are also known to feed upon fruit and insects. Black vultures have an even more varied diet and will eat eggs, nestlings, newborn mammals, fish, fruit, and shit. They will actually peck out the eyes of newborn calves that then go into shock and die, providing a feast for the birds.

Scientists studying vulture diets in coastal South Carolina examined 176 pellets found under communal roosts of vultures. The 3 most common animal remains found in these pellets included in order white-tailed deer, striped skunk, and raccoon. Human garbage was found in 45% of the pellets. Vultures in this region basically live on roadkill and garbage.

Black vultures scavenging a road-killed cat in Augusta, Georgia.

Vulture populations in North America have likely increased over the past 2 centuries because the increasing population of humans has provided them with such an abundance of food. They are uniquely evolved to consume rotting flesh without ill effects and are able to take advantage of the carrion supply resulting from the habits of humans. They have heads and necks naked of feathers, so blood and gore doesn’t accumulate on them, and they are resistant to bacteria toxic to most other animals. However, they do prefer fresher meat. They nest on the ground, and all they need is a thicket where they can hide their eggs and young. They can live for decades.

Vultures may have been just as common or perhaps more so during the Pleistocene when they scavenged the corpses of megafauna. There were a greater variety of species then. The 2 species that live today occurred then, though some scientists consider the Pleistocene black vulture (Coragyps occidentalis) to be a different species. It was on average larger but otherwise identical to the modern species. In addition, massive teratorns that likely tore open freshly deceased mammoths and ground sloths soared in the sky. 2 species similar to Old World vultures ranged into parts of North America. Fossils of the American griffin vulture and another species have been found in southwestern North America, and they may have ranged into other regions of the continent. New World vultures, the black vultures and turkey vultures, were formerly thought to be more closely related to storks, but genetic studies determined they are most closely related to ospreys and secretary birds. Old World vultures belong in the family that includes eagles, kites, and hawks.

Refererence:

Hill, J., et. al.

“Diets of Black Vultures and Turkey Vultures in Coastal South Carolina, USA with a Review of Species Dietary Information”

Southeastern Naturalist 21 (1) 2022

Bird Species Nesting in a Managed Grassland at Panola Mountain State Park, Central Georgia

December 23, 2021

In southeastern North America Native-Americans used to set fire to the woods every year, an activity that created a mosaic of open woodland and grassland. They also abandoned their corn patches when soil fertility became depleted, and warm season grasses would take over the fields. Many species of birds prefer to nest in a landscaped dominated by tall grasses consisting of little and big bluestem. Modern farmers suppress fires and plant non-native cool season grasses that grow in fall and winter. The hay from these species of grasses is mowed in the middle of summer. The mowing destroys bird nests, and as a consequence, birds that like to nest in grassy areas are in decline. Ecologists are restoring a native grassland in Panola Mountain State Park located just south of Atlanta, Georgia. They have replaced non-native cool season grasses with native warm season grasses, and they set fire to half of the tract every other year during late winter or early spring.

A recent study found 52 bird nests on this tract, and 35% of them were successful. 11 species of birds nest on the tract including bluebird, Carolina wren, common yellowthroat warbler, field sparrow, blue grosbeak, tree swallow, indigo bunting, red-winged blackbird, white-eyed vireo, Carolina chickadee, and killdeer plover. Bluebirds, Carolina wrens, and yellowthroat warblers were the most common species. Surprisingly, the most successful nests were located on the ground. The least successful nests were those located in nesting boxes near water or trails. The authors of this study think predators drawn toward water are more likely to find the nest boxes located there.

Eastern bluebird. Photo from the Indiana Audubon Society
Carolina wren. Photo from Salt Magazine.
Common yellowthroat. Photo from the Mitch Waite Group.

After reading this study I am inspired to visit Panola Mountain State Park, but I will wait until spring when birds are more active, hunting for insects to feed their young. The park also features a granite monadnock and a wetland.

Reference:

Allen, K. and K. Stumpf

“Avian Reproduction Success is Associated with Multiple Vegetation Characteristics at an Active Grassland Restoration Site in Central Georgia”

Georgia Journal of Science 79 (2) 2021

Birds Hunting Bats

August 6, 2021

During the Cretaceous mammals, including our ancient evolutionary ancestors, hid in the shadows from terrifying predatory dinosaurs. 65 million years later, some things never change because bats (along with rodents, rabbits, and small monkeys) still fall prey to the dinosaurs that didn’t become extinct–birds. 1 study compiled all accounts of diurnal birds hunting bats, and the authors cataloged 237 species of birds that have been recorded hunting bats. Some of the species are not surprising. 107 species of hawks and 36 species of falcons prey upon bats. Other species are more surprising. 94 non-raptor species from 28 families prey upon bats. The list of bird species that prey upon bats includes Mexican gray hawks, red-tailed hawks, Swainson’s hawks, Cooper’s hawks, bald eagles, and peregrine falcons. 1 species of falcon specializes in hunting bats and is even called the bat falcon (Falco refigularis). Owls probably kill more bats than hawks do because they are nocturnal and active when bats are most active. Species of owls that hunt bats include barn owls, barred owls, great horned owls, short-eared owls, and long-eared owls. Even some song birds prey upon bats. Brown jays, a tropical corvid, attack bats when they exit caves. And birds in the goat sucker family, such as Chuck-will’s-widows, swallow bats whole in flight. Some species of bats are particularly small and can be the size of large insects.

Red-tailed hawk hunting Mexican free-tailed bat. Photo from BBC Earth video on youtube.
This bird is actually called the bat falcon because it specializes in hunting bats. Photo from the Birds of the World website.
Even some species of songbirds eat bats, including this tropical brown jay. Photo from ebird.
Look at the gaping mouth of this Chuck-will’s- widow. They swallow small birds and bats whole while in flight. Photo from the Kiawah Island banding blogspot.

Mexican free-tailed bats live in colonies of hundreds of thousands. Raptors attack this species of bat in shifts. Red-tailed hawks attack the bats when they leave their cave in the evening; peregrine falcons attack the bats when they return to the cave in the morning. Birds normally attack bats when they are stragglers flying by themselves. Bats flying close together may be harder for birds to single out and hunt. For bats there is safety in numbers.

References:

Lee, Ya-fu; and Yen Man Kuu

“Predation on Mexican Free-Tailed Bats by Peregrine Falcons and Red Tailed Hawks”

Journal of Raptor Research 35 (2) 2001

Mikula, P.; F. Morello, R. Lucas, and D. Jones

“Bats as Prey of Diurnal Birds”

Mammal Review 46 (3) Feb 2016

Pleistocene Coots (Fulica americana)

June 17, 2021

Coots are 1 of the most common aquatic birds across North America and probably have been for millions of years. They are so abundant I didn’t have to rip off any pictures of them from google for this week’s blog entry. Instead, I searched through my own photos and found 1 I took of coots in Gainesville, Florida 2 years ago. Fossil remains of coots dating to the Pleistocene and/or Pliocene have been excavated from sites in Florida, Tennessee, Colorado, Utah, California, Oregon, New Mexico, Mexico, and the Bahamas. Coots prefer to congregate in flocks in the middle of a pond or lake that is surrounded by marshy vegetation. This type of habitat keeps them safe from land predators. Coots are usually found in freshwater. Female coots lay 1 egg a day for 10 days during nesting season for a clutch of 10. Their rate of reproduction along with their habitat preference allows them to thrive wherever wetlands are available. They mate for life and males spend a long time courting, but copulation lasts just 2 seconds.

Flock of coots at a bird sanctuary in Gainesville, Florida. I took this photo 2 years ago.

Coots are in the Gruiformes order which includes cranes, limpkins, and rails. Though they often hang out with ducks, they are not closely related to them. Their closest relatives are rails and gallinules–all members of the Raillidae family. They feed upon algae, pondweeds, grass, bulbs, roots, insects, snails, and fish. They are slow clumsy flyers and often fall prey to eagles, great horned owls, alligators, and bobcats. 80% of some bald eagle diets are made up of coots. To start flying from water, they have to run across the surface for some time.

Duck hunters frequently bag lots of coots because they are easier to shoot than ducks. According to the late George Leonard Herter, author of The Bull Cook and Authentic Recipes and Practices, coot meat tastes like a mouthful of mud. He noted the only way he could make the flesh palatable was to grind it up and put it in chili. Cajuns reportedly know how to make coot taste good, and they use it in a dish called gumbo de pouldeau. They remove every bit of fat from the meat, then soak it in water or milk overnight. The birds can then be used as an ingredient in gumbo. I’ve also seen videos on youtube of hunters removing the fat and soaking the meat in water. After this preparation they fry the meat and say it tastes like beef steak.

How to Cook Farm-Raised Quail

September 14, 2020

When I moved to Georgia during 1976 there was a beautiful old field between my neighborhood and a fishing pond.  We lived in the Cedar Creek subdivision located in Athens, Georgia, and I don’t know who owned the land with the pond we often trespassed upon.  Sadly, that land has been transmogrified into a shopping center parking lot.  Clarke County should have purchased the land and made it a park.  Back then, it was hilly and covered in tall yellow grass and within sight of a bottomland forest that grew alongside a chain of beaver ponds.  The outlet of the pond was a small waterfall that led to pools where large catfish often became trapped.  Crayfish and claw-less freshwater shrimp abounded in the creek, and signs of raccoons-their hand-like paw prints and discarded crayfish shells–could be seen all along the sandy creek side.  An otter slide led to part of the stream.  Deer darted into plum thickets.  One side of the 4 acre pond was bounded by a thick growth of alder; centuries old oaks shaded the other side where we usually fished.  Every Saturday morning while my friend and I headed toward the pond for another fishing adventure, we were frequently startled by the sudden drum-like explosion of a quail covey.  They could have stayed hidden in the tall grass and we would have never known they were there, but apparently we crossed a danger zone for them.  The explosive sound of a quail covey launch probably scares predators too.

Bobwhite Quail Covey by Lynn Bogue Hunt | eBay

Covey of Quail.

Populations of northern bobwhite quail (Colinus virginianus) currently are in decline, and I have not heard its 2 note call in several years.  Quail prefer old fields, grasslands, and open pine savannahs–habitats that have been replaced by 2nd growth forests, pine tree farms, subdivisions, and urban sprawl.  Bobwhite quail survived population declines during Ice Ages.  A study of bobwhite quail genetics determined their populations declined during the Last Glacial Maximum about 20,000 years ago but stabilized at the end of the Ice Age ~10,000 years ago.  Subfossil remains of bobwhite quail dating to the late Pleistocene have been excavated from 8 sites in Florida, 3 sites in Virginia, and 1 each in Georgia, Alabama, and Texas.  Quail remains along with those of ruffed grouse were the most common bird bones found in Kingston Saltpeter Cave in Bartow County, Georgia, dating to ~13,000 years BP.  Predators such as owls and hawks likely carried them into the cave.

Bobwhite quail belong to the New World quail family (Odontopharidae) group that is related to Old World partridges.  There are 32 species of quail in the Odontopharidae family, but the northern bobwhite quail is the only species native to eastern North America because this region has more continuous homogenous habitats.  They are a sister species to members of the quail family in the Callipepla genus which includes California, scaled, and Gamble’s quails.  Most other species in the Odontopharidae family are found in Mexico and South America.  The family likely originated there.

Meadows Quail Farm, Georgia Giant Bobwhite Hatching Eggs for sale

Photo of the inside of a quail farm in Georgia.  Nestlings like heat.

Kroger’s Supermarket sells a box of 4 dressed quail for $6.49.  Most other stores, if they have it at all, are double the price. These quail come from a farm in Greensboro, Georgia about a 90 minute drive from my house.

The best way to cook quail is to broil or grill them.  Unfortunately, most restaurants deep fry them–a culinary crime.

Farm-raised quail is readily available in supermarkets, and they are easy to prepare.  The best way to cook them is to sprinkle them with lemon juice, salt, and pepper; then stick them under a broiler for 15-20 minutes.  They can also be grilled.  Marinate them in your favorite marinade, and charcoal grill them for about 5 minutes per side.   (Wild quail may require a different cooking method.  I never cooked wild quail.)  Quail tastes a little better than chicken, but they don’t have much meat.  At least 2 birds per person should be served.  Deep-frying quail is a travesty, and they should never be cooked that way.  The breading covers up the delicate taste of the meat.

Reference:

Halley, S. ; et. al.

“A Draft De Novo Genome Assembly for the Northern Bobwhite (Colinus virginianus) Reveals Evidence for Rapid Declines in Effective Population Size Beginning in the Late Pleistocene”

Plos One March 2014

Pleistocene Phoebes (Sayornis sp.)

April 16, 2020

I frequently hear the call of the eastern phoebe (Sayornis phoebe), but I almost never see them.  So I was excited to photo a phoebe in my backyard last week.  My cat unsuccessfully stalked it while it was perched in a peach tree.  The bird landed on my fence, then picked off an insect on the ground and returned to the fence and ate it.  This is typical foraging behavior for phoebes.  They look for insects from above and drop to the ground to catch them.  Its mate observed this action from an higher limb.

Eastern phoebe on my fence.

https://www.allaboutbirds.org/guide/Eastern_Phoebe/sounds

Call of an eastern phoebe.

Phoebes belong to the tyrant flycatcher family or the Tyrannidae.  They are named for their aggressive behavior toward large predatory birds such as hawks and owls.  Phoebes mercilessly harass the larger birds until they leave the vicinity of the phoebe’s territory.  Phoebes live year round in my neighborhood–I hear their calls as early as February.  This species expands its range north during summer, and they do the reverse during winter.  They produce 2 broods per summer.  Although they prefer insects, they can subsist on berries and seeds when cold temperatures knock back insect activity.

There are 2 western species of phoebes–the black phoebe (S. nigricans) and Say’s phoebe (S. saya).  A common ancestor of all 3 species likely occurred all across North America about 5 million years ago.  Ecological changes associated with glacial/interglacial climate phases separated ancestral populations of eastern phoebes from their western cousins.  The same is true for a long list of bird species in North America.  There are eastern and western species of scrub jays, nuthatches, flickers, and many others.  Pleistocene-aged fossils of eastern phoebes have been excavated from Kingston Saltpeter Cave in Georgia, Bell Cave in Alabama, Natural Chimneys in Virginia, and Cheek Bend Cave in Tennessee.  Phoebes like to nest on natural or manmade structures, and caves provide favorable nesting locations, explaining why their fossil remains are often found in them.

Eastern Phoebe Range Map, All About Birds, Cornell Lab of Ornithology

Eastern phoebe range map.  Say’s phoebes occur almost exactly to the west of eastern phoebes.  Black phoebes are primarily a Mexican species.

There are 2 other species of tyrant flycatchers that occur or are supposed to occur in my neighborhood.  I often see eastern kingbirds (Tyrannus tyrannus), though I never hear them (the opposite of my experience with eastern phoebes).  Fossil evidence of eastern kingbirds has been found at 2 sites in Florida–Reddick and Vero Beach.  I’ve never seen a crested flycatcher (Myiarchus crista), perhaps because they prefer deep virgin forest where they can nest in hollow trees.

Pleistocene Blue Jays (Cyanocitta cristata)

December 7, 2019

When I was attending 3rd grade during the 1970/1971 school year, Perry Harvey came home with me everyday after school.  On occasion he could be reckless.  One unfortunate day he swung a baseball bat at an oak tree, and the bat rebounded, struck him in the head, and knocked him out cold; taking the old cliché “knock yourself out” to a literal reality.  Another day he made the mistake of picking up a baby blue jay that had fallen out of its nest.  Every blue jay in the neighborhood screeched and dive-bombed us.  He put the blue jay down, and the birds chased us into the house in a scene reminiscent of the Alfred Hitchcock classic The Birds. Like some other species of birds, blue jays practice communal defense.

YouTube video of a blue jay attacking a gardener.

Blue jays are intelligent birds from the corvid family which also includes crows and magpies.  They are well adapted for living in the temperate deciduous woods of eastern North America and have probably occupied that habitat for many millions of years.  However, I have been unable to find any studies of blue jay genetics, and I don’t know how long they have existed as a distinct species.  It seems likely they diverged from the common ancestor of the gray, Florida scrub, and Stellar’s jays before the beginning of the Pliocene over 5 million years ago.  Fossil remains of blue jays dating to the Pleistocene have been found at 3 sites in Florida, 1 site in Georgia, 1 site in Alabama, 1 site in Tennessee, and 3 sites in Virginia.

Blue jays played an important role in the spread of oak, beech, and chestnut trees north following the ends of Ice Ages.  Nuts and acorns are a major part of a blue jay’s diet, and they often carry excess food to distant locations where they hide them for later use.  A scientific study concluded blue jays were the sole reason oaks, beech, and chestnut were able to colonize deglaciated territory so rapidly after the end of the last Ice Age.  Squirrels invariably bury acorns and nuts so near the roots of the parent tree that they could not have been the agent of dispersal.  But blue jays carry nuts as much as an half a mile away.  Without blue jays there would be no oak or beech trees in eastern Canada and northern New England today.

Reference:

Johnson and Webb

“The Role of Blue Jays (Cyanocitta cristata) in the Post Glacial Dispersal of Fagaceous Trees in Eastern North America”

Journal of Biogeography 16 1989