Sea Cliffs of Shetland

 

Atlantic Puffin (Fratercula arctica) outside its nest burrow.
Sumburgh Head, Shetland, Scotland. 

Shetland is a splash of islands north of mainland Scotland.  This mostly treeless archipelago is in the North Sea, and many of the islands are bound by cliffs.   They are made of tilted sandstone dating from the Devonian Period over 300 million years ago. 

Sandstone cliff.
Isle of Noss, Shetland, Scotland.

We visited Shetland in June and found an abundance of life.  Hardy plants were growing on the cliffs and brought color to this rocky environment.  Sea Thrift (Armeria maritima) with its pink flowers and Red Campion (Silene dioica) dot the cliff tops.  

Sea Thrift (Armeria maritima).
Sumburgh Head, Shetland, Scotland. 

Red Campion (Silene diocia).
Sumburgh Head, Shetland, Scotland.

Ribwort Plantain (Plantago lanceolata), bright blue Spring Squill (Scilla verna) and the buttercup relative Marsh Marigold (Caltha palurtris) were flowering too.  Lichens encrust the rocks and cliff faces with shades of gray, green and bright yellow. 

Ribwort Plantain (Plantago lanceolata).
Sumburgh Head, Shetland, Scotland. 

Spring Squill (Scilla verna).
Sumburgh Head, Shetland, Scotland. 

Marsh Marigold (Caltha palustris).
Sumburgh Head, Shetland, Scotland. 

Lichens.
Sumburgh Head, Shetland, Scotland. 

While the geology and botany of the cliffs are engaging the real attraction is the birds.  Sea birds nest in vast numbers on the cliffs each summer.  They wheel through the sky giving their harsh cries and the ammonia smell of their droppings can be overwhelming.  Atlantic Puffins (Fratercula arctica) are elegant little birds in black-and-white plumage.  These iconic birds have stubby wings, a large multicolored, parrot-like beak, light gray face and a black mark above the eye.  Their bright orange webbed feet and waddling gait give them a comical look.  Atlantic Puffins dig burrows for their nests and fly from the cliffs to settle on the sea. There they dive for fish and return them to the nest to feed their mates and young.  

Atlantic Penguin,
Sumburgh Head, Shetland, Scotland. 

Atlantic Penguin,
Sumburgh Head, Shetland, Scotland. 

Atlantic Puffins are alcids classified in the auk family, the Alcidae.  Most alcids have variations on the black-and-white pattern of the Atlantic Puffins and nest on cliffs.  Razorbills (Alca torda) were present in small numbers.  They are about puffin-size and their black beak resembles the blade of a straight razor.  Razorbills are black above and white below with a white line on the beak.  

Razorbills (Alca torda) and Common Murres (Uria aalge).
Isle of Noss, Shetland, Scotland. 

Another alcid nesting on the cliffs is the Common Murre (Uria aalge).  In Britain these birds go by the name of Guillemots.  Common Murres are black or dark brown above with a white belly.  They have short, pointed beaks and black feet.  Most members of the population have a black or dark brown head but some, called Bridled Guillemots, have a white eye ring and white line extending back from the eye. They are present in vast numbers.  On the cliffs of the Isle of Noss we saw about 30,000 birds.  

Common Murre.
Isle of Noss, Shetland, Scotland. 

Common Murres.
Sumburgh Head, Shetland, Scotland. 

Bridled Common Murre with its white line and eye ring.
Isle of Noss, Shetland, Scotland. 

Gulls also find a home on the cliffs.  The Great Black-backed Gull (Larus marinus) is the largest gull in the world and is a predator, scavenger and pirate, stealing hard won fish from other sea birds.  This giant gull has a white head, belly and tail, with black on the back and upper wing surfaces.  It has pink legs and heavy yellow beak with a red spot.  

Great Black-backed Gull (Larus marinus).
Isle of Noss, Shetland, Scotland. 

The smallest gull on the cliffs is the Black-legged Kittiwake (Rissa tridactyla).  These petite gulls are white with a light gray mantle. They have yellow bills and their namesake black legs and feet.  Immature Black-legged Kittiwakes have a white head with a black smudge at the ear and a dark “W” pattern on the wings when seen from above.  They spend most of their lives at sea, returning to land only to nest on steep sea cliffs.  

Black-legged Kittiwake (Rissa tridactyla) on nest.
Isle of Noss, Shetland, Scotland. 

Immature Black-legged Kittiwake.
Sumburgh Head, Shetland, Scotland. 

The Sea Cliffs of Shetland are dazzling in their biological diversity and in the sheer number of birds present.  More on the cliffs and their life will come in the next installment of this blog. 

 

 

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.