Water quality on the shores of Lake Ontario near Rochester is the best it has been in decades
The EPA calls this area the “Rochester Embayment” and declared it a Great Lakes pollution hotspot in 1993.
Birds are among the most colorful land animals.
Our beautiful feathered friends have inspired our Democrat and Chronicle photographers for years and captured the imagination of many people who live on the shores of Lake Ontario.
Yes, the tropics are often known for having the most colorful birds, but American birds also display a wide range of striking colors. But how colorful are our American birds really?
Our network analyzed over 500 photographs of bird species provided by the Macaulay Library at the Cornell Lab of Ornithology, whose extensive media collection helps researchers identify and study color anomalies and rare bird colors. The species were selected based on data from Project FeederWatch, a citizen science program at the Cornell Lab that allows people to report sightings of birds they have seen near them.
Using a machine learning algorithm, we determined the dominant color of each bird photo.
Let’s take a look at the American kestrel, one of the smallest and most colorful falcons in the United States. It can be seen across the country circling open spaces in search of insects to eat. Running the photo through a machine learning algorithm resulted in this color palette for the bird.
The machine learning model determined that the predominant color for this bird is dark gray, meaning that this color group contains the most pixels. We ran the same analysis for all 559 bird species, resulting in a rainbow of colors representing U.S. birds.
It is important to mention that the predominant color depends on the lighting of the photo, the time of year in which it was taken, the sex of the bird and its age.
The colors of birds not only fascinate human observers. They also serve practical purposes: they indicate the general quality of the environment and play an important role in the survival and courtship behavior of the birds.
“Birds are guardians of the environment,” says Allison Shultz, assistant curator of ornithology at the Natural History Museum of Los Angeles County in California.
“The artist in me really fell in love with bird colors,” Shultz said, “but it was the biologist in me who discovered why they are so important and that they are actually worth studying.”
How do birds get their colors?
Understanding bird coloration combines biology and physics. Birds get their color in two main ways: pigmentation and the physical structure of the feathers—sometimes a combination of both.
Pigments are the chemical substances in animal and plant cells that provide color and absorb and reflect certain wavelengths of light.
Birds get some pigments, such as carotenoids, from eating fruits, seeds or insects. Carotenoids produce the bright reds, yellows and oranges seen in birds, and they are the same pigments that give carrots and pumpkins their distinctive color.
Birds also get their appearance from structural colors, which are created by the interaction of light with the microscopic structures in their feathers. Tiny air bubbles in the feathers refract and scatter light, creating bright colors that we can see.
Imagine the surface of a soap bubble or a rainbow-like oil slick. These phenomena, as well as the bright blue wings of the Morpho butterflies, are examples of the effects of structural color.
The Cardinal, a classic red bird, has pigments in its feathers that absorb all wavelengths except red and then reflect them back to us.
Carotenoid-based colors are often used as an indicator of a male bird’s quality, Shultz said. Brighter colors are often associated with better genes, stronger immune systems and higher reproductive success.
This concept, known as “redder is better,” reflects the idea that lighter-colored birds make better mates, says Richard Prum, an evolutionary ornithologist who teaches at Yale University. But Prum disagrees, saying the concept is a problematic way of “taking the beauty of the world and turning it into utility.”
While several North American birds have what appears to be green plumage, the turacos, native to sub-Saharan Africa, are the only birds that are truly green. Unlike other species, turacos owe their color to a copper-containing pigment called turacoverdin.
The Common Grackle and many shimmering hummingbirds display a dazzling display of color similar to that of a prism splitting light into a rainbow. Their iridescent feathers change color depending on the angle of view, adding to the appeal.
Colors of a bird
While bird species dazzle with countless colors, a single bird typically has multiple colors that our color palettes above do not capture.
According to Prum, the colorfulness of birds is based on evolutionary compromises and selection pressure.
The strongest pressure is what forces a bird’s feathers into a particular position, Shultz said, whether it is to impress a mate, to adapt to the environment or to stay cool in a hot place.
While bright colors can be great for social and sexual signaling, they are not so helpful in warding off predators.
Bright colors are usually signal colors for social interactions. They can be a way of saying, “Join my herd. We are members of the same herd,” Prum said.
That’s why these bright patches often appear on a bird’s head, throat or chest – areas that face other birds, Shultz said. A bird’s back is usually darker and more opaque, which serves as camouflage. This adaptation, known as countershading, helps the bird blend in and avoid drawing attention.
Male ruby-throated monarchs, for example, can flash their scarlet crown when excited or hide it when necessary.
Feathers that contain melanin are stronger, Shultz says, which is why birds often have dark wing feathers that make it easier for them to fly.
Do the colors change?
Even within a species, color can vary depending on age, season and gender.
Birds go through molting, the process of shedding old feathers and growing new ones, which can cause color changes. Most birds go through an annual molt, usually after the breeding season, Shultz said, but species like the goldfinch change their feathers twice a year.
“If you watch birds during molting at certain times of the year, they may look a little shaggy,” Shultz said. “That’s simply because they’re growing new feathers.”
Moulting helps birds keep their feathers in optimal condition for flight and allows them to replace worn feathers and remove parasites, Prum said.
Young birds may also look different from their older counterparts. This is because birds need time to signal their sexual maturity. Most songbirds reach this stage after one year, but bald eagles can take up to five years to develop their full adult plumage.
Males and females can look different – a phenomenon called sexual dimorphism. Females tend to be more monotonous because they have different ecological and social behavioral needs. However, sometimes the two sexes look identical, as in blue jays.
How do birds see colors?
As colorful as birds are to the human eye, we are actually “colorblind to birds,” Prum said. That’s because birds see an even wider range of colors than humans do.
“Birds live in a much more vibrant and colorful world than we do,” Shultz said.
Humans have three types of cones in their eyes for red, green and blue light. Birds also have an additional type of cone that allows them to see ultraviolet light.
Not only can birds perceive a wider range of colors, but they can also detect finer differences between colors. That is, birds can distinguish subtle nuances in shades of green that are imperceptible to us.
“Everyone always asks me, ‘Could you make bird-viewing goggles?'” Shultz said. “And we really can’t because our brains are just not designed neurologically to process that kind of information.”
Want to know more about the birds you saw in this story? Click on a color to find out.
Contribute: Javier Zarracina
Sources: US Fish and Wildlife Service National Digital Library, Getty Images.
Methodology: The photos were manually selected to find images of birds in a similar pose, with good lighting and of general quality. The background was removed from all photos and each photo was run through the K-Means algorithm to find the dominant color. K-Means works by dividing a bird’s colors into different groups or “clusters” to find the most representative colors. The color of each pixel is then assigned to the closest cluster center. The cluster with the most pixels becomes the dominant color.
