Tiny Plants Travel Around the World via Bird Wings
Birds in flight often arrange themselves in aerodynamically optimum positions, according to a new paper in thejournal Nature
that helps to explain how birds fly in such impressive formations. Lead researcher Steven Portugal and his colleagues focused their study on northern bald ibises, but many bird species also exhibit the amazing flight behavior. Portugal, a University of London Royal Veterinary College researcher, told Discovery News that birds could be using three things to achieve their flying precision: "(1) vision – watching the bird in flight to get all the information they need, (2) feathers – sensing the changes in pressure, wind etc. through their flight feathers, and (3) positive feedback – i.e. they just fly around and when it feels easier/better they stay in that position."
The researchers determined that birds try to find "good air," meaning airflows (not just wind, but even the air created by other flapping wings) that minimize their energy expenditure and help them to get where they plan to go. Conversely, birds avoid regions of "bad air" that could work against them.
Many birds fly in distinctive V-formations. Portugal said, "The intricate mechanisms involved in V formation flight indicate remarkable awareness and ability of birds to respond to the wing path of nearby flock-mates. Birds in V formation seem to have developed complex phasing strategies to cope with the dynamic wakes (turbulent air) produced by flapping wings."
H.K. Job, Wikimedia Commons
Military planes sometimes fly in what is known as an "echelon formation," which mirrors nearly the exact same flight formation of many birds. This particular bird version is a variation of the "V," only with a rounded edge.
The U.S. Navy's famous flight demonstration squadron The Blue Angels often flies in a trademark "diamond formation" once popularized by fighter-bomber pilots. In it, the pilots maintain an 18-inch wing tip to canopy separation. Birds can fly even more tightly together.
The term "murmuration" refers to a flock of starlings. These birds can create dramatic patterns in the sky, such as this one over marshlands near Tønder, Denmark. Other small birds, such as sandpipers, may also create what look to be dazzling aerial ballets in the sky as they fly en masse.
Rupert Ganzer, Flicker
Even birds flying very close to land can do so in remarkable unison. Here, a formation was photographed as the birds flew over the beach at Camperduin in the Netherlands.
Daniel Jolivet, Flickr
The classic "V" formation has all sorts of variations. In this case, three separate -- yet united -- groups create an arrow-like effect in the sky.
Mark Kent, Flickr
Alfred Hitchcock's classic horror film "The Birds" included many scenes where numerous birds blanketed the sky. Up close, these starlings look small and harmless but, as a huge murmuration, their power becomes evident.
From the earliest planes to those in design today, aircraft have been modeled after birds. It's no wonder. Every inch of this sleek northern bald ibis, snapped while flying over Tuscany, adds to the bird's flying prowess. Its 53-inch wingspan and powerful, synchronized wing beats must have captivated people in the ancient world too, since ancient Egyptians and other early cultures featured the birds prominently in their artwork and legends.
Bird wings harbor tiny plants that, with their avian transportation, can travel at least half way around the world, a new study finds.
The plants likely fall off here and there, colonizing regions far away from where each of the plant’s journeys began, according to the study, which is published in the journal PeerJ.
For the study, a team of 10 biologists, including three undergraduate students, collected American golden plover feathers in the field and used microscopes to closely examine the feathers.
The researchers found a total of 23 plant fragments that were trapped in the feathers of long-distance migratory birds that were about to leave for South America.
“We really had no idea what we might find,” one of the undergrads, Emily Behling, was quoted as saying in a press release.
The University of Connecticut senior added, “Each feather was like a lottery ticket, and as we got further into the project I was ecstatic about how many times we won.”
Clinging to the feathers were mosses, spores, plant pieces and more. Most are thought to be able to grow into new plants if they fall off, or if the bird knocks them off, in a suitable environment.
For example, about half of all known moss species can self-fertilize to produce offspring. Many can grow as clones. It only takes a single successful dispersal event to establish a new population. This helps to explain why moss might suddenly appear here and there in home gardens.
Co-author and PhD candidate Lily Lewis, also from the University of Connecticut, said, “Mosses are especially abundant and diverse in the far Northern and Southern reaches of the Americas, and relative to other types of plants, they commonly occur in both of these regions, yet they have been largely overlooked by scientists studying this extreme distribution. Mosses can help to illuminate the processes that shape global biodiversity.”
The “extreme distribution” previously puzzled scientists, since other common methods of distribution, such as wind dispersal, didn’t add up. The bird explanation makes more sense.
Each year, about 500,000 American golden plovers fly between the Arctic and South America. Now we know that the birds do this with hundreds of thousands of tiny plants trapped in their feathers.
Photo: An American golden plover about to take flight. Credit: Thomas C. Rothe/U.S. Fish and Wildlife Service