Black Birds, White Birds

 

Male Boat-tailed Grackle (Quiscalus major).
Palm Beach County, Florida.  

Snowy Egret (Egretta thula). 
Rio Tarcoles, Costa Rica.  

Birds exhibit a dazzling array of colors.  Think about the brilliant red of Scarlet Tanagers (Piranga olivacea) or the electric blue of Indigo Buntings (Passerina cyanea). Some wear coats of many colors like Painted Buntings (Passerina ciris).  But some birds are very plain, and the most extreme of these plain birds are the ones that are either pure white or pure black.  Why should a bird be just white or black?  Or in biological terms, what is the adaptive significance of black or white?  This question is surprisingly complex and there are many reasons for a bird to be white or black. 

Male Scarlet Tanager (Piranga olivacea). 
Dry Tortugas National Park, Florida. 

Male Indigo Bunting (Passerina cyanea).
Mecklenburg County, North Carolina. 

Male Painted Bunting (Passerina ciris). 
Palm Beach County, Florida. 

Some birds that live in arctic climates are white to blend in with the snowy background, for at least for part of the year.  Ptarmigans (Lagopus sp.) are white in winter, so they are hard to see against the snow.  They molt into brown plumage to better blend in with the environment in the warmer months when they breed.  This seasonal camouflage is highly adaptive.

Male Willow Ptarmigan (Lagopus lagopus)
in summer plumage.  Even in the breeding season
Willow Ptarmigans retain some white feathers. 
Nome,  Alaska.

Snowy Owls (Bubo scandiacus) are another species of white bird from the far north that can disappear into the white background as they hunt unsuspecting rodents. 

Snowy Owl (Bubo scandicus). 
Sax-Zim Bog, Minnesota. 

Not all white birds are restricted to icy high latitudes.  Great Egrets (Ardea alba) and Western Cattle Egrets (Ardea ibis) are found in temperate and tropical regions in both the eastern and western hemispheres. Snowy Egrets (Egretta thula) have a similar distribution in the New World.  These white birds are not trying to blend into the snow.  In fact, they are easy to see as they stand quietly along the side of a river or pond.  Egrets are predators of small animals, often fish, and their white color makes it harder for their prey to see against the light sky.  

Great Egret (Ardea alba).
Palm Beach County, Florida. 

Western Cattle Egret (Ardea ibis).
Palm Beach County, Florida. 

Snowy Egret.
Huntington Beach State Park, South Carolina.

At the other extreme there are black birds.  There is a whole family called blackbirds, the Icteridae.  Not all the members of this family are black, and some are brilliant like the orioles, but many live up to their name and are black. Male Boat-tailed Grackles (Quiscalus major) and Common Grackles (Quiscalus quiscula) are black with a sheen of iridescence that might look purple at one moment then gold the next. Female Boat-tailed Grackles are not black, but a rich brown and female Common Grackles are black but with less iridescence.   Iridescence in these male blackbirds is a signal to females that they have good genes, good nutrition and would be good mates. 

Male Boat-tailed Grackle show iridescent feathers.
Palm Beach County, Florida. 

Female Boat-tailed Grackle.
Palm Beach County, Florida. 

Male Common Grackle (Quiscalus quiscala)
with iridescent plumage.  
Rowan County, Florida. 

Red-winged Blackbird (Agelaius phoeniceus) males are black but have a bright red and yellow patches on their shoulders, the epaulettes. By contrast, female Red-winged Blackbirds are streaky brown.  This phenomenon of different colors in the male and female in a species is called sexual dichroism and many birds exhibit this characteristic.  In the case of Red-winged Blackbirds the females are cryptically colored to better hide while incubating eggs. 

Male Red-winged Blackbird (Ageliceus phoennicus).
Palm Beach County, Florida. 

Female Red-winged Blackbird showing her cryptic plumage.
Palm Beach County, Florida. 

Both the males and females of  American Crows (Corvus brachyrhynchos) and Fish Crows (Corvus ossifragus), are black.  Many other members of this family, the Corvidae, are also black but this group also includes some brightly colored birds like Blue Jays (Cyanocitta cristata). 

 

American Crows (Corvus brachyrhynchos).
Mecklenburg County, North Carolina. 

New World vultures (Cathartidae) are usually dark and one, the Black Vulture (Coragyps atratus) is truly black.  It has a black head, black legs and black feathers, except for the flight feathers that are light silvery gray.  

Black Vulture (Coragyps atratus).
Cartago, Costa Rica. 

Black Vulture landing showing gray on the wing tips.  
Mecklenburg County, North Carolina. 

Some birds are both black and white.  In the breeding season, Snow Buntings (Plectophenax nivalis) are white on the belly and head with black wings and some black tail feathers.  During the winter these birds of the arctic regions migrate south.  Before this migration, Snow Buntings molt into a white and brown plumage to make themselves harder to see in areas with less snow.  

Snow bunting (Plectrophenax nivalis).
Utqiagvik (Barrow), Alaska. 

White Ibises (Eudocimus albus), American White Pelicans (Pelecanus erythrorhynchos) and Wood Storks (Mycteria americana) are white birds with black flight feathers, the primaries and secondaries.  Black color in feathers is caused by the pigment melanin and melanin is found throughout the living world from bacteria to plants and from fungi to animals.  Melanin produces color, including black and pigment also physically strengthens feathers.  The tips of the flight feathers undergo a great deal of stress in flight.  Adding melanin makes the feathers more resistant to damage and wear.  

White Ibises (Eudocimus albus) landing.  They have black tips
 on their primary feathers to strengthen them.
Palm Beach County, Florida. 

American White Pelicans (Pelecanus erythrorhynchos).
These pelicans have black primary and secondary feathers. 
Rowan County, Florida.

Wood Stork (Mycteria americana).  Like American White Pelicans,
Wood Storks have black primaries, secondaries and tail feathers. 
Palm Beach County, Florida. 

Sometimes a bird that would normally be pigmented is totally or partially white.  Albinos do not make melanin or other pigments. They have white feathers, beaks and feet.  Their eyes are pink because blood vessels in these organs are visible.  They are more more easily seen by predators and often have visual and other impairments.  Albinos usually do not survive long enough to reproduce.  

A partially leucistic female
Northern Cardinal (Cardinalis cardinalis). 
Rowan County, North Carolina. 

True albinos are rare.  A more common occurrence is leucistic birds.  They have some pigmentation but have areas of white. Leucistic birds may have just a small patch of white or lack pigments over most of their bodies.   Both albinism and leucism are genetically determined.  

A leucistic Song Sparrow (Melospiza melodia).
Rowan County, North Carolina. 

A  leucistic White-crowned Sparrow (Zonotrichia leucophrys).
Guadalupe Mountains National Park, Texas. 

Partially leucistic Northern Cardinals (Cardinalis cardinalis) have visited our yard in the past several winters. We had a leucistic Song Sparrow (Melospiza melodia) feeding near the Yadkin River and a leucistic White-crowned Sparrow (Zonotrichia leucophrys) was sheltering from the wind on a blustery winter day at Guadalupe Mountains National Park in Texas.  Leucistic birds stand out both to us and to predators.  Like albinos, leucistic animals may not to survive long in nature but in suburban areas with abundant food and lower predation they have a better chance of living and reproducing. 

White Ibis.
Huntington Beach State Park, South Carolina. 

Male Red-winged Blackbird.
Palm Beach County, Florida. 

White or black feather color in birds is adaptive.  Birds may be either white or black as camouflage, or to signal to potential mates they are a worthy partner.  White feathers keep birds cooler so they can be used for controlling body temperature. You might expect white birds to be more common in the tropics.  However, black birds and white birds can be seen living in the same tropical environment, so temperature regulation is not the only answer to why birds are black or white.  Black pigmentation protects birds from ultraviolet radiation, and the number of black species increases closer to the equator where UV levels are high.  So the reasons why birds are white or black are many and varied.  No simple answer can explain all the different black or white birds in the world.

Privet, Honeysuckle and Wisteria Got Away

 

Chinese Wisteria (Wisteria sinensis) flowers. 
Rowan County, North Carolina. 

Sometimes things get away.  Three common plants that were imported into the United States for their utility, flowers and fragrance have escaped domestication and turned invasive.  Japanese Honeysuckle (Lonicera japonica), Chinese Wisteria (Wisteria sinensis) and Chinese Privet (Ligustrum sinense) have left the gardens and gone into the wild where they are choking out native plants.  As their names imply, all three of these plants originated in eastern Asia.  

Chinese Privet (Ligustrum sinsese) flowers. 
Rowan County, North Carolina. 

Chinese Privet.
Rowan County, North Carolina. 

Chinese Privet is a shrub or small tree in the Olive family, the Oleracea.  It was brought to North America in the mid-19^th century as an ornamental and hedge plant.  It escaped cultivation and now covers thousands of acres in the southeastern United States.  Chinese Privet produces abundant white flowers that develop into purple fruits.  These are eaten by birds that disperse seeds in their droppings.  It is called one of the worst invasive plants by the US Department of Agriculture and out competes natives.  It is especially common in the understory of swamp forests.  

Japanese Honeysuckle (Lonicera japonica) flowers. 
Rowan County, North Carolina. 

Japanese Honeysuckle overgrowing wild shrubs.
Rowan County, North Carolina. 

Japanese Honeysuckle is a vine that is native to Japan, Korea and eastern China. It is classified in the family Caprifoliaceae that includes a number of native honeysuckles.  Japanese Honeysuckle was imported from Japan in the early 1800s for its white and yellow flowers and its sweet aroma.  This vine was also used to prevent erosion and as food for deer.  Japanese Honeysuckle also made an escape and is often found in sunny, disturbed areas where it can grow into dense tickets of vines.  The vines shade out other plants and prevent germination of native trees. 

Chinese Wisteria vines in full flower.
Rowan County, North Carolina. 

Chinese Wisteria flowers.
Rowan County, North Carolina. 

Chinese Wisteria is a woody vine in the Pea family, the Fabaceae.  It originated in China but has been introduced to many temperate regions of the world.  Chinese Wisteria grows across the ground and up trees where it produces cascades of purple to white flowers in the spring.  The flowers are not only beautiful, but they also have a delicate fragrance.  These features made Chinese Wisteria a landscape staple.  In the southeastern United States Chinese Wisteria has become invasive covering extensive areas. It can even overgrow and kill large trees. 

Chinese Wisteria covering trees.
Rowan County, North Carolina. 

Japanese Honeysuckle, Chinese Privet and Chinese Wisteria were brought to the United States and other locations around the world with the best intentions.  But these plants got away causing serious environmental problems. Removal of these invasive plants costs millions of dollars each year.  Despite the ecological disruptions and the money it takes to remove invasive plants, they continue to be available for sale in nurseries around the country.  They will be planted anew and get away to cause further problems.

 

Wonders of Spring

 

Male Prothonotary Warbler (Protonotaria citrea).
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

The world is awash with wonders, big and small.  As spring has unfurled and we have gotten out in the woods these wonders have revealed themselves.  

 Tiny wasps are out and laying their eggs on plants.  The wasps synthesize and inject plant hormones at the site of egg deposition, and this causes a proliferation of plant tissue resulting in galls.  The eggs hatch and the larvae eat the galls and grow.  The larvae then metamorphose into a mature wasps that chew their way out of the gall.  Oaks (Quercus sp.) are common hosts for gall wasps. 

Lobed Oak Gall Wasp (Andricus quercusstrobilanus) Gall.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

We found two distinctive galls on oaks this spring.  One was produced by the Lobed Oak Gall Wasp (Andricus quercusstrobilanus).  The woody, polyhedral gall has multiple chambers that taper down to their common attachment point on the stem of an Overcup Oak (Quercus lyrata).  Each chamber hosted a single wasp larva.  In the Lobed Oak Galls we found the wasps had already emerged because each chamber had a small exit hole. 

Wool Sower Gall Wasp (Callirhytis seminator) Gall.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Internal structure of Wool Sower Gall Wasp Gall.
Salisbury Greenway, Salisbury, North Carolina. 

A second gall was made by the Wool Sower Gall Wasp (Callirhytis seminator).  The gall was on a White Oak (Quercus alba), the usual host for this wasp and was about two inches in diameter. This gall was interesting because it was white and fuzzy, very unlike the Lobed Oak Gall.  The gall contained many small brown structures each of which had a single wasp larvae.  We never did see the tiny adult wasp that made either of these galls, but we know they are around. 

Catbriar (Smilax sp.) young fruits. 
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Catbriar mature fruits.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Catbriar (Smilax sp.) is an evergreen vine with sharp spines.  The vines sported new growth and was in flower and early fruit.  One vine had both tiny new fruits and mature fruits from last year.  

American Sycamore (Platanus occidentalis) bark. 
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

American Sycamore (Plantanus occidentalis) trunks have beautiful bark. On a mature tree the young bark near the top is white, older parts of the trunk are mottled with patches ranging from white to green to brown that are described as camouflage.  The oldest bark is dark brown and scaly.  

Spicebush Swallowtail (Papilio troilus). 
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Spicebush Swallowtail (Papilio troilus) butterflies are flying.  These large black butterflies have a distinctive pattern of white markings and the characteristic swallowtails.  They lay their eggs and the larvae develop on Northern Spicebush (Lindera benzoin).  

Asian Lady Beetle (Harmonia axyridis).
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Asian Lady Beetles (Harmonia axyridis) are our familiar Lady Bugs. These well-known insects are native to eastern Asia and because they are voracious predators of aphids have been introduced around the world as a form of biological pest control.  The bright orange and black coloration is a warning signal to potential predators that they taste bad.  This point was dramatically brought home when a friend who likes to eat things from the wild popped an Asian Lady Beetle into his mouth.  He instantly started to spit out beetle parts, to choke, spit and generally suffer from trying to consume an Asian Lady Beetle. 

Green Treefrog (Dryophutes cinereus) in a frog tube.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Northern Cricket Frog (Acris crepitans).
Six Mile Creek Greenway, Mecklenburg County, North Carolina. 

Northern Cricket Frog.
Six Mile Creek Greenway, Mecklenburg County, North Carolina. 

Frogs are calling and hoping around the wetlands.  A Green Treefrog (Dryophytes cinereus) was using a plastic pipe as a safe perch. Northern Cricket Frogs (Acris crepitans) had just crawled from a vernal pool.  Some of these tiny frogs are plain brown and others are brown with a bright green Y on their back.  

Yellow-crowned Night Heron (Nyctanassa violacea).
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Yellow-crowned Night Herons (Nyctanassa violacea) haunt the swamp, stalking crayfish.  These short-necked, big-eyed herons do indeed hunt at night but are sometimes abroad in the day. 

 

Blue-gray Gnatcatcher (Polioptila caerulea) collecting lichens.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Blue-gray Gnatcatcher approaching its nest.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Blue-gray Gnatcatcher on its nest.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Blue-gray Gnatcatcher on its nest.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Blue-gray Gnatcatchers (Polioptila caerulea) are among the earliest migrating songbirds to arrive in the spring.  They spend the winter in Florida and points south and on their return waste no time in starting their nests.  Blue-gray Gnatcatchers collect spider and Eastern Tent Caterpillar (Malacosoma americanum) silk.  They use silk to hold together lichens that make up their nests.  They are tiny birds and build a tiny nest that looks like a lichen-covered lump on a branch. 

 

Male Prothonotary Warbler with its bands.
Catawba College Ecological Preserve. 
Salisbury, North Carolina.

Another small bird that returns from the tropics is the Protonotary Warbler (Protonotaria citrea).  They breed in southeastern swamps after spending the winter in Central American and northern South America.  Protonotaries are golden-yellow with black beaks, eyes and legs.  Their loud song echoes through the wetlands as males set up their breeding territories.  This spring a male Prothonotary Warbler was defending an area near where he was hatched.  Catawba College biology professor Dr. Joe Poston banded this bird with a unique pattern of plastic and metal bands in April 2024.  Because of these bands this particular Protonotary can be identified in the field with binoculars.  This bird continues to return to his home swamp and may do so for years.

These are just some of the wonders we have seen this spring by walking the woods, fields and swamps near our home.