The Laysan albatross (Phoebastria immutabilis) is a large seabird that nests primarily on small, isolated islands throughout the North Pacific. Known for their large wingspans and graceful flight, Laysan albatrosses have predominantly white plumage accented with dark feathers on their back and wings. But what exact colors make up the plumage of these majestic birds? Here we explore the specific hues and patterns that comprise the distinctive coloration of the Laysan albatross.
White Plumage
The bulk of a Laysan albatross’s plumage consists of bright white feathers which cover the bird’s head, neck, belly, and underside of wings. This predominantly white coloration serves an important purpose – camouflage. When flying over the open ocean, the white underside of the albatross blends in with the water below, making them difficult for predators to spot from below. The white head and neck also provide some camouflage against the sky when viewed from above.
Additionally, the brilliant white color reflects sunlight, helping to keep the bird cool in warm environments. Their nesting islands in the Pacific receive intense, year-round sunshine which can heat up dark surfaces. The white plumage reflects solar radiation and prevents the albatrosses from overheating.
Color Producing Structures in Feathers
The bright white appearance of Laysan albatross feathers is produced by the microscopic structure of the feathers. Feathers gain their colors from pigment granules deposited in the feather, and from the physical structure of the feather itself.
The white color of Laysan albatross feathers comes from structural color, not pigment. The feathers contain bubbles of air and keratin in a uniform array. This structured arrangement of air and keratin scatters light of all wavelengths, producing the effect of white. Very little light is absorbed, giving the feathers their brilliant, luminous quality. Melanosomes, the pigment granules that produce darker feather colors, are present only in low amounts. This combination results in feathers that appear stark white.
Black and Brown Accents
While most of their plumage is bright white, Laysan albatrosses have dark feathers on some areas of their wings and back. These darker feathers provide a few key benefits.
First, the dark coloration absorbs heat from the sun, helping warm the bird’s core and major flight muscles. The wings and back make up a relatively small surface area on the bird, meaning the dark plumage can absorb solar radiation without overheating the entire body.
Second, the dark feathers may strengthen and protect the flight feathers. The melanin pigments in darker feathers help make them harder and more resistant to wear. This provides added protection for the critical wing and tail feathers.
Finally, the dark wings and back provide some degree of camouflage when viewed from above. When seen from below, the white underside blends in with the sea; from above, the dark upper side blends better against the darker ocean waters.
Wing & Back Feather Colors
The darker feathers on a Laysan albatross’s wings and back display a range of black, brown, and gray hues. The exact shades can vary somewhat between individual birds. Generally, these feathers display the following color patterns:
– Blackish-brown coverts and flight feathers along the leading wing edge.
– Dark gray-brown feathers on the upper side of the wings and along the trailing edge.
– Brown and black mottled back feathers, often fading to gray near the nape of the neck.
These darker hues are produced by melanin pigments deposited in the feather structure during growth. Higher levels of eumelanin result in blacker shades, while more pheomelanin produces browner tones. The mélange of dark melanin-infused feathers provides the Laysan albatross with a distinctive color pattern.
Bill, Eyes, and Feet
In addition to their plumage, some other external features of Laysan albatrosses exhibit key colors. These include the bill, eyes, and feet.
Bill
The albatross’s large, hooked bill is colored pale pink, tan, blue, gray, or yellow. The bill color is related to diet – birds that feed more on crustaceans tend to have paler bills, while those that eat more fish and squid have darker bills. The bill also frequently develops vertical dark stripes along the top and bottom that fade to pinkish near the hook. These lines help direct fish into the inner bill cavity.
Eyes
Laysan albatrosses have dark brown or black irises which surround the pupil and control light intake. The contrast of the dark iris against the bird’s white head makes the eyes more visible and expressive at a distance. It may also aid in signaling and mate selection.
Feet
The feet of Laysan albatrosses are light pink with black nails and dark grey scaly plaques on the tops of the feet. The light pink color with dark accents provides camouflage when the birds float on the sea, obscuring the outline of the feet below the water’s surface.
Chick Plumage
Newly hatched Laysan albatross chicks have downy gray plumage unlike the adult white and black patterns. This charcoal colored down helps keep the chick warm and protected in the nest. Within a few months, the chicks molt to juvenile plumage.
Juvenile Plumage
As juvenile birds that have left the nest, Laysan albatrosses display drabber colors than the brilliant white adults. Their juvenile plumage features:
– Gray-brown head, neck, back, and wings
– Dark smudges around the eyes
– White rump
– Light pink bill with some darker spots
– Pink feet with black nails
This subdued coloration likely makes the fledgling and juvenile birds less visible to potential predators. Once they reach adulthood at around 5 years old, they develop the full white and black adult plumage.
Role of Colors in Behavior
The distinctive color patterns of Laysan albatrosses play an important role in communication, signaling, and mating behaviors. Here are some of the key ways their coloration facilitates albatross behavior:
Signaling & Communication
The contrasting patches of white, black, and gray feathers provide highly visible patterns that albatrosses likely use to communicate over long distances. Subtle movements that expose or highlight certain plumage areas may help relay information to other birds.
Mate Selection & Bonding
During mating dances, pairs appear to assess the plumage patterns of potential mates. The vivid contrast and pristine condition of plumes may signify health, age, or experience to help guide mate choice. Preferred individuals are likely those exhibiting the brightest white feathers and sharpest demarcations between white, black and gray plumage.
Parent-Chick Recognition
Adult Laysan albatrosses can locate their chicks in busy colonies by their voice and plumage patterns. The unique variations in chick down color and patterns allow returning parents to identify their own offspring. As chicks age and approach fledging, parents learn their juvenile plumage patterns for continued recognition.
Geographic Variation in Color
Across the wide range of the Laysan albatross in the Pacific, isolated populations on different island groups show some subtle geographic variations in coloration. These likely resulted from random genetic changes and shifts in environmental conditions.
Northwestern Hawaiian Islands
– Mostly bright white plumage with clean delineations between white and dark feathers
– Dark brownish-black wing and tail feathers
– Pale pink-tan bills
Bonin Islands, Japan
– Duller, dingy white plumage
– Dark slate gray wings and back
– More extensive dark markings along back of neck
– Blue-gray bills
Torishima, Japan
– Intermediate white plumage, not as stark white as Hawaiian birds
– Dark brownish wing and tail feathers
– Yellow- or blue-gray bills
Despite these subtle regional variations, the overall bright white, black, and brown color pattern remains consistent throughout the species. The differences likely reflect minor genetic adaptation to local conditions.
Use of Color Analysis in Research
Detailed color analysis of Laysan albatross plumage has provided researchers with helpful information about diet, flight patterns, and environmental exposures. Some key uses of color research include:
Assessing Diet Composition
By analyzing subtle variations in bill colors of albatrosses from different colonies, researchers have deduced relative proportions of squid, fish, and crustaceans in their diets. This allowed better understanding of how birds utilize distant foraging grounds.
Tracking Flight Routes
Chemical analysis of feather pigments showed albatrosses from certain colonies had higher mercury exposures. Researchers determined these birds foraged along mercury-rich currents, helping trace migratory routes.
Monitoring Plastic Pollution
Many albatross chicks die from eating plastics floating in the ocean. Researchers have measured plastic consumption by analyzing chemical tracers from pollutants in feather samples of juveniles. This helps track risks for different populations.
Assessing Mate Choice
By using spectral imaging, scientists found Laysan albatrosses choose mates with the brightest plumage displays. This technique analyzes subtle color differences impossible to discern visually, illuminating mating cues.
Conclusion
From their primarily bright white plumage, accented with blackish-brown and gray tones, to the colorful shades of their bills, eyes, and feet, Laysan albatrosses exhibit a range of hues well adapted to their lifestyle. The colors play an integral role in communication, mating, regulating temperature, camouflage, and protecting critical flight feathers. Additionally, analyzing the chemical composition and microscopic structures within albatross feathers has provided researchers with valuable insights into their ecology and conservation needs. Moving forward, continued color analysis will likely unveil further secrets about the life history of these majestic seabirds.