Swallowtails

 

A yellow female Tiger Swallowtail Butterfly (Papilio glaucus).
Rowan County, North Carolina. 

Swallowtail butterflies are large, brightly-colored insects that are found on all continents except Antarctica.  North America hosts about thirty species of swallowtails and eight or so live in the southeast.  These butterflies get their name from the tails on their hindwings that are reminiscent of the forked tails of Barn Swallows (Hirundo rustica).  The tails, along with eye-like spots on the hindwings, give the appearance of a head at the back of the butterfly.  A predator zeroing in on this false head might get a bite of wing as the butterfly escapes.  A number of these attention-grabbing butterflies closely resemble each other.  They make up a mimicry complex where non-toxic species have evolved to look like a poisonous one.  

A male Tiger Swallowtail. This butterfly has worn wings and 
has lost most of its tails. 
Rowan County, North Carolina. 

Eastern Tiger Swallowtails (Papilio glaucus) are the largest butterflies in our area.  They range from the Canadian border to the edge of the Great Plains and to the Atlantic and Gulf Coasts.  Eastern Tiger Swallowtails are yellow with black stripes on the forewing that give them the tiger name.  The rear edges of the wings are bordered in black and have yellow spots.  Male Eastern Tiger Swallowtails are always yellow but females can either have the same pattern as the males or they can be black with yellow marginal spots.  The hindwings of females also bear orange and blue eye spots near the swallow tails. 

A black female Tiger Swallowtail.
Rowan County, North Carolina. 

Black female Eastern Tiger Swallowtails mimic their toxic relative, the Pipevine Swallowtail (Battus philenor), a butterfly that lives in the same area.  The black form of Eastern Tiger Swallowtail is more frequent in the southern part of the range where Pipevine Swallowtails are more common.  Many plants play host to Eastern Tiger Swallowtails including Tulip Poplar (Lireodendron tuliperia) and other members of the Magnolia family.  Eastern Tiger Swallowtail butterflies can often be seen flying around the canopy of these large trees. 

Pipevine Swallowtail (Battus philenor). This toxic butterfly
is the model for several mimic species.
Davidson County, North Carolina. 

Pipevine Swallowtails have a similar range as the Eastern Tiger Swallowtail but is more common in the southern tier of states.  They are black with iridescent blue on their hindwings.  Pipevine Swallowtails lay their eggs on Pipevine plants (Aristolochia sp).  The caterpillars eat the leaves and store the distasteful, carcinogenic and poisonous aristolochic acid made by Pipevine.  When the caterpillars metamorphose into butterflies, they retain the toxin and are protected from their avian predators.  Other species of butterflies besides the Eastern Tiger Swallowtail also resemble Pipevine Swallowtail. 

Underside view of a Pipevine Swallowtail. 
Davidson County, North Carolina. 

Black Swallowtails (Papilio polyxenes) have black wings with yellow spots.  Male Black Swallowtails have large yellow spots and on the hindwings. Just in front of the tails, they have red and blue spots.  Females have the same pattern but with smaller yellow spots.  Like female Eastern Tiger Swallowtails, Black Swallowtails are protected by their mimicry of Pipevine Swallowtails.  Black Swallowtails lay their eggs on plants in the Apiaceae, the carrot family.  Larvae can be found happily eating Queen Anne’s Lace (Daucus carota), Flat Parsley (Petroselinum crispum) and other plants in this family. 

Female Black Swallowtail (Papilio polyxenes).
Colleton County, South Carolina. 

Spicebush Swallowtails (Papilio troilus) are also part of the mimicry group and have a similar pattern to Pipevine Swallowtails.  Spicebush Swallowtails get their name because they lay their eggs on Spicebush (Lindera benzoin), a shrubby tree of swamps and rich woods. 

Spicebush Swallowtail (Papilio troilus).
Davidson County, North Carolina. 

Palamedes Swallowtails (Papilio palamedes) are found on the Coastal Plain of the southeast and are particularly common in swamps.  These large, dark brown butterflies when seen from above have yellow bands and spots on the wings.  The underwings of Palamedes Swallowtails have yellow, orange and blue markings and a characteristic yellow strip on the body. Many butterflies, including swallowtails, drink mineral laden water from moist soil.  This behavior is called puddling. We found a large mixed group of swallowtails puddling at the Alligator River National Wildlife Refuge in Dare County, North Carolina. 

Palamedes Swallowtail (Papilio palamedes) puddling. 
Alligator River National Wildlife Refuge, North Carolina. 

Two Palamedes and an Eastern Tiger Swallowtail.
Alligator River National Wildlife Refuge, North Carolina. 

Video of Palamedes and 

Eastern Tiger Swallowtails puddling.

Alligator River National Wildlife Refuge, North Carolina. 

A striking swallowtail that is not in the Pipevine Swallowtail mimicry complex is the beautiful Zebra Swallowtail (Protographium marcellus).  Zebra Swallowtails are found in most of the eastern United States.  The host plant for Zebra Swallowtails is Pawpaw (Asiminia triloba).  Pawpaws produce a neurotoxin and the Zebra Swallowtail is one of the few species that is resistant to the toxin.  The caterpillars and adults of Zebra Swallowtails are protected as a result of eating Pawpaw. Zebra Swallowtails have triangular wings with black and white stripes that suggest their namesake mammal.  Zebra Swallowtails have long tails and bright red eyespots on the hindwings.   

Zebra Tiger Swallowtail (Protographium marcellus).
Rowan County, North Carolina. 

Many cultures associate butterflies with change and transformation.  In Christianity the metamorphosis from chrysalis to flying creature represents resurrection.  The flight of the Swallowtails is a welcome sight in our woods and fields.

Pokeweed

 Pokeweed (Phytolacca americana) is an impressive weed.  It is tall, brightly colored and poisonous.

Pokeweed (Phytolacca americana) leaves and fruit in late summer
Rowan County, North Carolina. 

Pokeweed emerging in spring.
Young leaves may be eaten after boiling.
Rowan County, North Carolina. 

Pokeweed is native to eastern North America and can reach heights of over six feet.  It grows from a large taproot that puts out leaves in the spring.  The robust stems of Pokeberry are bright reddish purple, contrasting with the green of the large leaves.  By early summer Poke makes small white flowers that become fruits that start green and turn purple.  Another common name for Pokeweed is Inkberry.   Pokeweed berries can be crushed and used as a natural ink, paint or a fabric dye. 

Pokeweed in summer showing its reddish purple stems.
Rowan County, North Carolina. 

Pokeweed contains a large number of toxic molecules. People ingesting Pokeweed may experience vomiting, cramps, bloody diarrhea and in some cases death.   Despite its toxicity some people eat Pokeweed.  Only the young leaves are selected and they must be boiled to remove the poisons.  The boiled leaves are eaten as poke (polk) salad.  

Pokeweed in flower.
Rowan County, North Carolina. 

Poke salad was a traditional part of the diet of poor people in the south. This dangerous delicacy was immortalized in the song “Polk Salad Annie”.  This song from the 1960s, was written by Tony Joe White and covered by none other than The King, Elvis Presley.  A great line from the song goes “Polk Salad Annie, gator got your granny. Everybody said it was a shame, because her momma was working on a chain gang.”   This song gives a glimpse of the culture that prized poke salad. 

Pokeweed with green fruit.
Rowan County, North Carolina. 

While Pokeweed is poisonous to mammals, birds are not affected.  The ripe, purple berries of Pokeweed are relished by Gray Catbirds (Dumetella carolinensis), Northern Mockingbirds (Mimus polyglottos), American Robins (Turdus migratorius) and other fruit eating birds.  The fruit is digested by the birds and the seeds are released in purple bird droppings.  Many a car has been decorated with purple splashes by avian pokeberry eaters.  

Mature fruits of Pokeberry are deep purple.
Rowan County, North Carolina.

By winter, all the berries have been eaten and the leaves have dropped off.  The stems fade from the bright color of summer to a skeletal white.  But, Pokeweed is waiting underground for another season of exuberant growth and berry making.  

Pokeweed stems in late winter.
Rowan County, North Carolina. 

Farmers don’t like Pokeweed.  Cattle and horses are sometimes poisoned by eating the plant.  But I enjoy seeing Pokeweed in the summer along roadsides and the edges of fields. 

 

 

The Tortoise and the Owl

 

Burrowing Owl (Athene cunicularia) perched above its burrow.
Florida Atlantic University, Palm Beach County, Florida.

The Gopher Tortoises (Gopherus polyphemus) and Burrowing Owls (Athene cunicularia) of Florida are on the edge.  They inhabit harsh habitats like scrub and prairie, with well-drained sandy soil. Unfortunately for them, people also covet these habitats.  First, their land was converted to farms, then to suburban housing tracts.  The tortoises and owls are being squeezed by the human population in a fast-growing state.  

Gopher Tortoise (Gopherus polyphemus).
Canaveral National Seashore, Florida. 

Burrowing Owl at the mouth of its burrow.
Florida Atlantic University,
Palm Beach County, Florida.

While Gopher Tortoises and Burrowing Owls may share the same environment, they lead very different lives.  Gopher Tortoises are found on the Coastal Plain of the southeast from eastern Louisiana to South Carolina and down the length of the Florida peninsula.  Gopher Tortoises have high domed shells and, like their namesake rodent, dig burrows. The front legs of Gopher Tortoises have large scales for protection and large claws for digging in the sand.  The rear legs are described as elephantine with large, round flat feet.  Gopher Tortoise burrows provide shelter to many other animal species ranging from Eastern Diamondback Rattlesnakes (Crotalus adamanteus) to Burrowing Owls.  Gopher Tortoises are vegetarians that may survive 60 years in the wild and over 90 years in captivity.  

A pair of Burrowing Owls.
Florida Atlantic University,
Palm Beach County, Florida.

Burrowing Owls have an even wider distribution than Gopher Tortoises, from Patagonia in South America to the high plains of Canada.  The Florida population is isolated.  Florida Burrowing Owls are over 900 miles from the western members of their species.  But during recent ice ages there was a continuous band of scrubland linking Florida to western North America and the owls inhabited it all.  Burrowing Owls are small, standing only about 10 inches tall and are active in the daytime. They have brilliant yellow eyes and their feathers are brown and white. Burrowing Owls long legged and spend much of the time standing near the mouths of their burrows. They feed mainly on insects, small mammals and reptiles. 

Gopher Tortoise.
Florida Atlantic University,
Palm Beach County, Florida.

A Burrowing Owl peering from the mouth of its burrow.
Florida Atlantic University,
Palm Beach County, Florida. 

The Burrowing Owls of western North America use the burrows of rodents like prairie dogs.  Members of the Florida population use the burrows of Gopher Tortoises but can also dig their own tunnels.  Sometimes you can see an owl tossing sand from a burrow in progress.  The burrows serve as shelter and as nest sites.  The original habitat of Florida Burrowing Owls was the Florida scrub and prairies.  As these areas were developed, the owls moved to residential areas, golf courses and airports.  

 Video of Burrowing Owl. Florida Atlantic University, Palm Beach County, Florida. 

Gopher Tortoise emerging from its burrow.
Ocala National Forest, Florida. 

Both Burrowing Owls and Gopher Tortoises are listed as threatened species in Florida.  But despite legal protection, the growth of the human population and relentless real estate development continue to push these marvelous creatures to the edge. 

Light and Water

 

A small section of a rainbow showing the
spectrum of visible light.  Otto Lake, Alaska.

The physics is well known, even simple. Reflection, refraction, absorption.  But the interaction between water and light produces spectacular effects. 

A wine glass filled with water.  The water
appears colorless. 

Look at a glass of water. It appears clear, colorless. But if you get a long enough column of water it takes on a blue hue.  Look down into a deep lake or the ocean and the blue color jumps out at you. Water absorbs the red wavelengths of light leaving the blue light and giving it the color.  

The Atlantic Ocean off Hatteras, North Carolina.
The ocean here is deep and appears deep blue because the red wavelengths
of light are absorbed by the water.  

Crater Lake fills the caldera of an ancient volcano.
The lake is nearly 2000 feet deep and is deep blue. 
Crater Lake National Park, Oregon. 

In addition to absorption, reflection also contributes to the color of water.  Reflection from the sky can change the appearance of water.  A cloudy, gray sky will be reflected from the surface and give a completely different look to water.    

Gray sky reflected on the surface of
Kachemak Bay, Alaska.

Sunrise and sunset reflected in water can produce dramatic colors.  As the sun moves, the reflections on water change with great speed.  

A beautiful sunrise reflected in Murrells Inlet,
Georgetown County, South Carolina. 

Pink morning light on Lake Norman, Mecklenburg County, North Carolina. 

Warm sunset reflected from the surface of 
Lake Norman, Mecklenburg County, North Carolina. 

Reflections of plants growing in water and animals standing in still water gives a mirror-like effect, and makes a nearly exact copy of the original. 

Snowy Egret (Egretta thula) and its reflection.
Huntington Beach State Park, South Carolina. 

Water plants reflected in still water.
Green Cay Wetlands, Palm Beach County, Florida. 

Black-necked Stilt (Himantopus mexicana) reflected
in Radicha Creek, Kleberg County, Texas. 

Blue-winged Teal (Anas discolor) and reflection.
Wakodahatchee Wetlands, Palm Beach County, Florida. 

Some of the most amazing interactions of light and water take place in the sky.  Rainbows are made by refraction of light through tiny water drops that act as prisms. The droplets divide the white light of the sun into its constituent wavelengths of red, orange, yellow, green, blue, indigo and violet.  This is the spectrum of visible light.  Many of us learned the famous mnemonic, ROYGBIV, to keep the order of the rainbow colors straight.  In a rainbow, red is on the outside of the arc and violet on the inside.  

Rainbow at Otto Lake, Alaska. 

We view rainbows with our backs to the sun. Each color, each wavelength, is refracted a different amount causing the rainbow to form.  A rainbow is really circular, but often part of the circle is below the horizon so we see it as an arc. The angle of refraction of light in a rainbow is about 42^o so the rainbow fills an 84^o section of the sky.  

Sunbow and sundogs.
Sax-Zim Bog, St. Louis County, Minnesota. 
Photo courtesy of Ms. Judy Walker. 

Another refraction-based phenomenon is a sunbow or halo.  A sunbow is a spectrum in a circle that surrounds the sun.  Sunbows are caused by refraction of sunlight through ice crystals and the angle of refraction is 22^o.  This refraction produces a halo that fills 44^o of sky, about half that of a rainbow.  Since sunbows have a smaller angle than rainbows you are much more likely to see the entire circle of a sunbow. The order of colors in a sunbow is the opposite of a rainbow with violet on the outside and red on the inside.  

Sundog. Huntington Beach State Park, South Carolina. 

Sundogs are related to sunbows and their technical name is perihelial arcs.  They are another refraction effect caused by ice crystals and are found at 22^o to the right and left of the sun.  Sundogs sometimes appear isolated and other times are associated with sunbows.  There are sundogs in the photo of the sunbow above. 

Interactions between light and water have significant cultural meaning around the world. In ancient Greek mythology, Narcissus fell in love with his own reflection in a pool of water and stared at it until he died.  This story gives us the term narcissism.  Rainbows are considered deities in diverse cultures.  Many Australian Aboriginal groups revere the Rainbow Serpent and in ancient Greece, Iris was the rainbow goddess.  Hawaii is renowned for its rainbows and there the goddess Anuenue took the form of a rainbow and served as a messenger for her immortal brothers.  In the Genesis, God sent the rainbow as a sign to Noah that the world would not destroyed again by flood.  Ancient Norse mythology has a Rainbow Bridge from Asgard to Earth.  In our time, the rainbow flag has become the banner for gay pride. On a lighter note, Ireland gave us the story of a pot of gold at the end of the rainbow, guarded by a leprechaun. In the Wizard of Oz, Dorothy longs to go over the rainbow from a monochrome Kansas.  Science and culture give us different views of water/light interactions.  This is a measure of the impact these phenomena have on all people. 

Sunset reflected in Lake Norman,
Mecklenburg County, North Carolina. 

Wayward Birds

 

A vagrant female Calliope Hummingbird (Selasphorus calliope)
in Charlotte, North Carolina. 

Some birds spend their whole lives in one area.  Others undertake long distance migrations that cross continents and oceans.  But sometimes birds wander and end up where they are not supposed to be.  These out of place birds are called vagrants. The term vagrant conjures up images of homeless people who wander and just scrape by.  Vagrancy in birds is probably much less dire. In some cases vagrancy establishes new populations and even species. 

There are several explanations for bird vagrancy.  Some birds are blown out of their normal range by storms.  Hurricanes are famous for bringing sea birds far inland.  Migratory birds will sometimes overshoot their destination and end up further north or further south than other members of their species.  Other vagrants seem to have a faulty navigation system and migrate in the wrong direction.  Still others just seem to wander.  Some seem to have taken a page from the American naturalist, Bugs Bunny, who famously said, “I know I should have taken a left turn at Albuquerque”.

In December 2019, we saw a Heermann’s Gull (Larus heermanni) on the beach at Lake Worth, Florida.  This large gull normally lives on the west coast of North American from British Columbia in the north to Baja and the coast of Mexico in the south.  Adult Heermann’s Gulls are gray with a white head, while juvenile birds are all gray.  These handsome gulls are rare but regular visitors to the east coast. 

A juvenile Heermann's Gulls (Larus heermanni)
on the beach.  Lake Worth, Florida. 

Another gull that crosses the continent with some regularity is the Slaty-backed Gull (Larus schistisagus).   This large gull breeds along the Pacific coast of East Asia, from Japan to Russia.  Slaty-backed Gulls are regular visitors to Alaska but also wander down the Pacific coast of North America, across to the Great Lakes and some even reach the shores of the Atlantic.  We tracked down an adult Slaty-backed Gull at the Horry County Landfill near Myrtle Beach, South Carolina in January 2022.  There were over 10,000 gulls at the landfill but we managed to find this rare one without much trouble thanks to good advice from the landfill workers and other birders.  

An adult Slaty-backed Gull (Larus schistisagus) 
at the Horry County Landfill, South Carolina. 

The Slaty-backed Gull ignored all the landfill activity
 around it and enjoyed the rich pickings.
Horry County Landfill, South Carolina. 

Western hummingbirds sometimes wander east, usually during the winter. The Calliope Hummingbird (Selasphorus calliope) is the smallest native hummingbird in the United States and breeds in the western mountains.  It then undertakes a long migration to central Mexico for the winter.   But some birds make that wrong turn and end up in New England in the fall and some winter in the southeast.  We saw a Calliope Hummingbird coming to a feeder in Charlotte, North Carolina in December 2017.

Female Calliope Hummingbird.  This picture caught the bird
defecating.  Many birds lighten their load before taking flight.
Charlotte, North Carolina. 

Rufous Hummingbirds (Selasphorus rufus) are probably the most common of the western hummingbirds that come east.  They nest in the northern Rocky Mountains and migrate to Mexico.  But many winter across the central and eastern United States, some even reach Florida.  Male Rufous Hummingbirds have an iridescent orange throat, reddish brown tail, back and flanks.  Females also show the rufous color but not as vividly as the males.  

A female Rufous Hummingbird  (Selasphorus rufus) was visiting a hummingbird feeder
at Riverbend Park in Catawba County, North Carolina in December 2021. 
Rufous Hummingbirds regularly winter in this park.

Bullock’s Orioles (Icterus bullockii) are striking orange, black and white birds that are normally found west of the Great Plains.  While most of their species migrate to Mexico some head east.  The Bullock’s Orioles that winter in eastern North America often come to feeders that they may share with Baltimore Orioles (Icterus galbula).  In the 1970s and 1980s lumping bird species was in scientific fashion.  At that time the Bullock’s and Baltimore Orioles were combined into one species, the Northern Oriole.  New genetic research in the 1990s caused them to be separated again.  North Carolina hosts Bullock’s Orioles each winter and they are a welcome visitors.  

A juvenile male Bullock's Oriole (Icterus bullockii) visiting a feeder in January 2018.
Charlotte, North Carolina. 

Another brilliant western bird that sometimes winters in the east is the Western Tanager (Piranga ludoviciana).  These birds are yellow, black and white and the adult males sport red on their heads.  The eastern vagrants often hang around feeders eating suet and seeds. 

 

This male Western Tanager (Piranga ludoviciana) stayed during the winter
of 2018-2019 in Salisbury, North Carolina 

Some birds drift north from their tropical homes and Florida hosts many of them.  In the winter of 2020-2021 a number of vagrants flew up to the Keys and so we went to see them.  We found a Red-legged Thrush (Turdus plumbeus) at the Key West Tropical Forest and Botanical Garden perched in a fig tree.  This placid bird showed no concern about the many birders who stood under its tree and gawked.  The Red-legged Thrush is a robin-sized bird with a dark gray head, body, wings and tail, an orange belly and bright red feet and eye ring.  This handsome bird’s normal range is the West Indies from Puerto Rico to Cuba and north to the Bahamas.  

A Red-legged Thrush (Turdus plumbeus) at the 
Key West Tropical Forest and Botanical Garden, Florida.

The second tropical visitor we saw on that trip to the Keys was a Cuban Pewee (Contopus caribaeus).  This small flycatcher is native to Cuba (naturally) and the Bahamas but one spent the winter at the National Key Deer Refuge on Big Pine Key.  The Cuban Pewee resembles the Eastern Wood Pewee (Contopus virens) that breeds in North American but the Cuban species has a crescent-shaped white mark, a teardrop, behind the eye.   

Cuban Pewee (Contopus caribaeus) at the Key Deer Refuge, Florida. 

Studies suggest that many vagrants do not survive, but vagrancy can play in important role in dispersing birds and possibly establishing new populations.  Cattle Egrets (Bubulcus ibis) are native to Africa but flew across the Atlantic to colonize South America in 1870s.  Then they spread to North America where they established breeding populations by the 1950s.  In the 1960s these long-range wanderers reached the Galapagos Islands off South America.  The famed Galapagos Finches (Geospizinae), found on those same islands, evolved from vagrant American finches that were blown to those volcanic dots in the Pacific. 

Cattle Egrets (Bubulcus ibis) are notorious vagrants 
and have spread from Africa to South
and North America in the last 135 years.
Wakodahatchee Wetlands, Palm Beach County, Florida.  

Climate change may increase the number of vagrants. Vagrancy could be the first sign of an expanding range for species. These wayward birds do wander but whatever their fate, they can delight the birders who see them.