Birds to Watch
Here are some amazing stories about birds, to inspire wonder and admiration of these varied and beautiful flying creatures.
Feather gallery: Let’s start with a show of feathers. As illustrated in the film Flight: The Genius of Birds, a feather is a highly complex structure, light and flexible yet strong. From the soft downy inner feathers to the long, strong flight feathers, they perform multiple functions for birds. One of those functions is sexual display. For birds, the males are usually the fairer sex in terms of cosmetic beauty. National Geographic posted a gallery of some of the more flamboyant species, illustrating the tremendous variety in shape and structure of feathers from head to tail.
Hawk trick: How do raptors avoid wing damage in turbulence? They tuck their “collapsible” wings under their body very briefly when a strong gust hits. That’s what Science Daily says about experiments with a flight recorder mounted on the back of an eagle. It only takes about 0.35 second for the “wing tuck” maneuver (during which the bird is essentially falling), but it prevents damage and saves energy for the flight muscles that would be severely strained trying to maintain balance in a strong gust. The test eagle named Cossack performed this maneuver on average three times a minute. Don’t expect small aircraft to try this trick any time soon; their strategy is to stay grounded in strong winds.
Duck trick: Ducks and other waterfowl feel for their food underwater. To do this, their bills must be very sensitive to touch. Researchers from Yale studied duck bills and found the reasons for “acute mechanosensitivity in tactile-foraging waterfowl.” Publishing their findings in PNAS, they said this “least well understood” sense is due to a higher density of somatosensory neurons in ducks than in mice, and that they are more densely packed. Neurons for temperature, though, were reduced—probably because waterfowl often feel their way around in very cold water.
Desert migrators: Some Australian shorebirds have an uncanny knack for crossing the desert and locating small temporary ponds over a thousand miles inland from their usual beachfront homes. Sid Perkins, writing for Science Magazine, tells how matchbox-sized geolocators mounted on the birds tracked their routes. After rains, groups of birds would leave from different locations and converge on the same small pond. In one case, the birds flew 2200 km (1367 miles) in 2.5 days. Some took off weeks after the rains, perhaps planning their arrival for the hatching of brine shrimp. Scientists are not sure what cues the birds use to find the ephemeral ponds, which might only fill with water once every 2 or 3 years.
GPS contest: As many have heard, this year’s Nobel Prize in Physiology or Medicine went to scientists who discovered the brain’s internal GPS (see Science Magazine)—the sense, located in the hippocampus, that helps us navigate with a mental compass and map. Less reported was a story by Sana Suri on The Conversation that says “‘Inner GPS’ of bird brains may be better than that of humans.” Some seed-caching birds have a larger hippocampus than other species, and display an extraordinary sense for location memory. For example, the Clark’s nutcracker excels at “making more than 5000 caches of seeds in the autumn and recovering them seven to nine months later in the spring.” On a related subject, Science Daily posted an interesting description about how our own spatial memory depends on geometrical relationships and the brain’s ability to “anchor” our mental compass with landmarks.
Perching in the Tree of Life: “They are some of the brightest, loudest, oddest-looking, least-understood birds on the planet, and thanks to a comprehensive new evolutionary ‘tree of life’ generated for the tropical cotinga family of South America, the door is now open to new discoveries about the more than 60 species in this amazingly diverse group of birds,” begins a report in Science Daily. Claims of success for a cotinga phylogenetic tree came at a price, however:
They wanted to learn if the evolution of differently-colored males and females in this bird group (sexual dimorphism) is directly linked to a breeding system in which males have multiple mates (polygyny). Darwin first theorized that the increased pressure of sexual selection in polygynous birds spurred the development of color differences between the sexes. This appears to be true for many species — but not the cotingas. When Berv and Prum examined patterns of evolution for these two traits across their new tree of life, it turned out that they didn’t perfectly match up. The statistics they calculated also supported the conclusion that these traits may be evolutionarily “de-coupled” in the cotingas.
Readers skeptical of the evolutionary speculating, or who consider “sexual selection” theory to be a “zombie idea” (1/24/14), can at least enjoy the photo of a bright orange Andean cock-of-the-rock. The article gives this description of other species of cotingas: “Some have bulbous crests, long fleshy wattles, or Elvis-worthy pompadours in addition to electric blue, deep purple, or screaming orange feathers.” Readers can also decide whether a fossil bird egg found in Brazil has anything to do with evolution (Science Daily).
Roast eagle: On a political note, California has (thankfully) dropped plans for another solar power plant that poses a risk to birds, PhysOrg reported. As politically popular as alternative energy has become, it often follows the Law of Unintended Consequences. The collected light in a large solar plant near the border with Nevada gets so hot, it “can cause some birds to ignite in midair.” Birds and bats have also been frequent casualties of wind farms.
The more you learn about birds, the more you will doubt evolution, and instead appreciate them and marvel at the design built into them. Appreciating birds will also promote efforts to protect them from political schemes. With these news items in mind, why not watch a bird today?