Birds depend on their color vision for selecting mates, hunting or foraging for food, and spotting predators. Until recently, ultraviolet vision was thought to have arisen as a one-time development in birds. But a new DNA analysis of 40 bird species, reported Feb. 11 in the journal BMC Evolutionary Biology, shows the shift between violet (shorter wavelengths on the electromagnetic spectrum) and ultraviolet vision has occurred at least 14 times.
The researchers mapped the birds' evolutionary relationships using data from their study and others. The color mutation that made bird lineages with violet vision evolve to see in ultraviolet and vice versa occurred at 14 different times in their map, and probably even more among all birds, Ödeen noted.
Several Great Tinamou females may lay their shiny, unspeckled turquoise eggs on contrasting brown leaf litter in the same depression or scrape on the ground without building an actual nest of sticks or mud. Cornell PhD Patricia Brennan, now at the University of Massachusetts, Amherst, studied these birds in Costa Rica, noting that the eggs are not camouflaged or well concealed despite the threat of predation. Brennan suggests that egg color is a signal to other females, drawing their attention to the nest and promoting synchronous laying. The benefit to the birds is that, even if a predator does strike, it cannot eat all the eggs and those of any one individual stand a better chance of surviving.
This table is one of the earliest known color charts. Waller created it as a tool for describing plants and animals. Collectors and scientists could compare their specimens to this table and use the names provided to identify the colors of leaves, bark, flowers, feathers, plants, and animals.
Bradley sought to educate adults and children about the physics and psychology of color. In his book Elementary Color he emphasized that color instruction for children should employ a simple naming system. He promoted his color wheel as a device that could scientifically match and measure colors. When spun rapidly, overlapping colored disks mix colors before your eyes. Different combinations of disks create a multitude of hues based on measured proportions.
Nudibranchs: These shell-less mollusks absorb the pigments of their food sources into their normally white bodies, reflecting the bright colors of sponges and cnidarians, which include jellyfish and corals.
Maryland's flag bears the arms of the Calvert and Crossland families. Calvert was the family name of the Lords Baltimore who founded Maryland, and their colors of gold and black appear in the first and fourth quarters of the flag. Crossland was the family of the mother of George Calvert, first Lord Baltimore. The red and white Crossland colors, with a cross bottony, appear in the second and third quarters. This flag first was flown October 11, 1880, in Baltimore at a parade marking the 150th anniversary of the founding of Baltimore. It also was flown October 25, 1888, at Gettysburg Battlefield for ceremonies dedicating monuments to Maryland regiments of the Army of the Potomac. Officially, it was adopted as the State flag in 1904 (Chapter 48, Acts of 1904, effective March 9, 1904).Maryland law requires that if any ornament is affixed to the top of a flagstaff carrying the Maryland flag, the ornament must be a gold cross bottony (Chapter 862, Acts of 1945; Code General Provisions Article, secs. 7-201 through 7-203).Maryland GovernmentMaryland Constitutional Offices & AgenciesMaryland Departments Maryland Independent AgenciesMaryland Executive Commissions, Committees, Task Forces, & Advisory BoardsMaryland Universities & CollegesMaryland Counties Maryland MunicipalitiesMaryland at a Glance Maryland Manual On-LineSearch the Manuale-mail: email@example.com
TH: His thought was that they were straining to see these other colors that were kind of just outside of their reach. And then - their kid - would inherit that effort. Or their kid would just be a little bit better.
Backyard birdwatchers dedicate a lot of time and resources into attracting a diversity of birds to their yards. While we go to great lengths to offer food and water, there comes a point when you wonder if there is something else you can do to attract more birds.
Birds have the same three photoreceptors as humans, but in greater numbers. This is why researchers believe they can see more variations and intensities of colors than we do. However, unlike humans, birds have a fourth photoreceptor that allows them to see ultraviolet light. With this in mind, there may be some truth to color playing a role in attracting birds to backyard bird houses and bird feeders.
One key factor when choosing a color for your bird house or bird feeder is the location. The safety of birds should always be considered as predators will always be a threat. Colors that help a bird house or bird feeder blend into the environment are best in that regard. Gray, dull green, tan, or brown, are colors that make bird houses or bird feeders less visible to predators because they blend in best with natural surroundings. Avoid metallic or fluorescent colors as they tend to be so bright, they offer no cover from predators.
From a marketing standpoint, many bird houses are sold in colors that coordinate with certain bird species. Red and pink tend to be the most common feeder colors for hummingbirds. Bird houses and bird feeders for goldfinches are often yellow, while blue is a common color for bluebird products. Because of their love for oranges, oriole bird houses and bird feeders are often colored orange.
Unique to birds and their dinosaur ancestors, feathers have evolved into impressive biological structures that come in a surprising diversity of colors and forms. Here, we cover the breadth of feather biology by looking at feathers from a variety of scientific viewpoints including their anatomy, function, development, and evolution.
The drab contour feathers covering the body of some birds may seem lackluster, but subtle brown patterns can create an impressive degree of camouflage in forested environments. Famous for hiding in plain sight, the Common Potoo (Nyctibius griseus) is covered with feathers that mimic the colors of the tree branches it perches on. Adding to the disguise, the potoo will adjust its posture and close its eyes into tiny slits, making itself appear to be an extension of the tree.
Not all camouflage has to be drab. For example, the vibrant green contour feathers of male Eclectus Parrots (Eclectus roratus) serve a camouflage function during foraging trips in the rainforest canopy. Back at the nest cavity where the green stands out against the brown tree bark, the male coloration aids in the intense competition with other males to win female mates. Male Eclectus Parrots likely evolved their green coloration as a tradeoff between effective camouflage and display. This is a rare example of feathers that allow birds to both hide and show off.1
Have you ever wondered why some birds hatch naked while others are covered in a coat of fuzzy feathers? Many young water birds must be able to swim and forage alongside their parents almost immediately after hatching. These precocialprecocialpree-KO-shuldescribing a chick that is mobile quickly after hatching and requires little parental care chicks hatch with a full coat of natal down to keep them warm in cold water. Young Mute Swans (Cygnus olor) for example, hatch with a fuzzy coat of natal down and after a few weeks, replace the natal down with an inner layer of adult down and an outer coat of contour feathers. In contrast, the young of many songbirds are born completely naked.
Feathers are dead structures that cannot repair themselves when damaged. Because a healthy and functional coat is critical to survival, each year birds shed their old feathers and then grow a whole new set. This moltingmoltin birds, the process of losing and regrowing feathers on a regular cycle process is a carefully timed affair in which feathers are shed and regenerate in turn over a period of weeks so the bird can maintain its protective outer layer and ability to fly. Once the new set of feathers has matured, molt is complete and new growth only occurs before the next molt cycle when feathers are accidentally lost.
One such scientist is Kim Bostwick, who used this integrated approach to untangle the mysteries of a bird whose feathers work like a musical instrument. This may sound like an outrageous idea, but male Club-winged Manakins of Central and South America use a highly modified feather structure to play a powerful one-note tune. Strong evolutionary pressure on these males to attract females has made them unique in the bird world, but it took years of scientific investigation by Bostwick and colleagues to work out the full story of how and why these birds sing with their wings.
Kim Bostwick began her study of Club-winged Manakins by asking questions about how they sing with their wings. She spent years piecing together how the birds accomplish this feat mechanically, but she did not stop there. Because Kim had always been interested in evolution, she also asked questions about how their specialized feathers and associated behaviors evolved. This led her to study other birds closely related to Club-winged Manakins to see what behavioral innovations occurred in their evolutionary history that contributed to the display we see today. It turns out that the behavior evolved through a series of small steps, including short wing clicks and backwards hopping, into one of the most unusual displays in the animal world. Like Niko Tinbergen, Kim is one of the many scientists who prefer to ask scientific questions from many angles, going beyond the mechanics to make discoveries about function, development, and evolution.
The Indians have always loved shells onaccount of their bright colors. No doubtthey many times tried to paint their facesthe same color. They used to make moneyfrom the pink or purple portions of them. 2b1af7f3a8