Tag Archives: hummingbird

Female hummingbirds avoid harassment by looking like males

Harassment is not acceptable, whether you’re a human or an animal — or at least it shouldn’t be. Nevertheless, it’s something that still happens to many, including female hummingbirds. They are frequently targeted by their male counterparts, which has forced them to search for solutions. According to a new study, they’ve found one and it’s all about evolution. 

Image credit: Flickr / Doug Greenberg.

Jay Falk, a biologist from the University of Washington, has long been working with white-necked jacobins (Florisuga Mellivora), spectacular hummingbirds from all across Central America. They are unmistakable thanks to their white belly and tail, in the case of the males, and their green upperparts and white-scaled green or blue throat. 

We tend to think of hummingbirds as friendly and cute but their world is actually much harsher. For instance, the males frequently act as bullies. When they see a female, they peck, catcall or body slam them. This is sometimes about sex, but other times, just about asserting dominance. Unsurprisingly, female hummingbirds would love to have a way of avoiding this. 

As it turns out, evolution was on their side. Over time, females jacobins ditched their usual greenish outfits and tended to copy the sapphire feathers of males. In other words, the birds that looked more like males would suffer less bullying and were more likely to spread their genes. And it turns out they were successful, as now males and male-like females seem to be living in harmony, according to a study by Falk and his fellow researchers. 

“One of the ‘aha moments’ of this study was when I realized that all of the juvenile females had showy colors,” Falk said in a statement. “For birds that’s really unusual because you usually find that when the males and females are different, the juveniles usually look like the adult females, not the adult males, and that’s true almost across the board.”

A trip to Central America

Falk became a regular in Panama, where he traveled many times to observe the jacobins interact. He observed most juveniles, both male and female, have colorful plumage. However, as they grow older, only 80% of the females change their outfits. The rest keep their flashy feathers, which makes them indistinguishable from most males. 

Image credit: The researchers

This was very surprising for Falk and his team, who decided to do an experiment to see how the birds interact based on their coloring. They used a feeder with nectar to attract the hummingbirds and added taxidermy mounts in order to tell how they could alter the interactions of the wild birds. They used three combinations of two mounts. 

When the researchers looked at the acts of aggression between the stuffed and the real hummingbirds, they found that the stuffed colorless females were often attacked much more than the stuffed colorful females. Even birds of other species ended up joining the attacks against the colorless jacobins, according to the study’s findings. 

Some of the attacks are because of sexual attraction, with males wanting to mate with as many females as possible, Falk said. But there are other reasons too, including hunger. Hummingbirds are always seeking for food due to their very high metabolic rates, so they end up picking a fight between each other to get the much-desired nectar.

“Hummingbirds are such beloved animals by many people, but there are still mysteries that we haven’t noticed or studied,” Falk said in a statement. “It’s cool that you don’t have to go to an obscure unknown bird to find interesting and revealing results. You can just look at a bird that everyone loves to watch in the first place.”

The study was published in the journal Current Biology. 

Hummingbird eyes can detect UV, allowing them to see the world in colors that humans can’t even imagine

The male broad-tailed hummingbird can see combinations of colors like ultraviolet plus green or ultraviolet plus red. In fact, the bird’s throat, which looks like magenta to us, is likely perceived as ultraviolet plus purple by birds.

Compared to many birds, such as the delightful hummingbird (Colibri), humans are color-blind, says Mary Caswell Stoddard. The Princeton University professor, along with colleagues, showed that hummingbirds are able to discriminate various ultraviolet (UV) color combinations, allowing the birds to see the world in additional colors that humans can’t even comprehend.

A hidden world of ultraviolet

Humans essentially see the world in a combination of three colors: red, green, and blue. Each primary color is detected and decoded by corresponding specialized cones in the eye.

The hummingbird, however, has a fourth color cone, which extends its color-vision range into the ultraviolet. But, how exactly does this additional color cone morph the bird’s vision?

In their new study, Stoddard and colleagues left their labs at Stanford and traveled to Gothic, Colorado, for fieldwork in the alpine meadows each summer over the course of three years.

Their work mainly focused on how hummingbirds sense non-spectral colors, which are combinations of hues from widely separated parts of the color spectrum. A clear example of a non-spectral color is purple, which combines blue and red wavelengths of light, but not green. In contrast, teal (blue-green) and yellow (green-red) are blends of neighboring colors in the spectrum.

In fact, purple is the only non-spectral color that humans can sense. But birds should theoretically be able to see up to five, thanks to their extra color cone type. In addition to purple, birds should also be able to see combinations of ultraviolet and red, green, yellow, and purple, respectively.

“Most detailed perceptual experiments on birds are performed in the lab, but we risk missing the bigger picture of how birds really use color vision in their daily lives,” Stoddard said in a statement. “Hummingbirds are perfect for studying color vision in the wild. These sugar fiends have evolved to respond to flower colors that advertise a nectar reward, so they can learn color associations rapidly and with little training.”

The research team performed a series of experiments with wild broad-tailed hummingbirds (Selasphorus platycercus) that had two feeders at their disposal that they could use. One contained sugary water, the other just plain water.

Each feeder had an LED tube that flashed various colors. The tube that corresponded to sugar water emitted one color, while the other emitted a different color — with an important caveat.

To you or I, both colors look the same, i.e. green. However, the LEDs can display a broad range of colors, including non-spectral colors like ultraviolet plus green. If the birds could indeed see additional non-spectral colors, this should be obvious from their choice of feeders.

The researchers swapped the positions of the rewarding and unrewarding tubes at random intervals of time to make sure the birds weren’t going to the same location to pinpoint the treat. They also performed control experiments to rule out the influence of smell or anything other non-vision-related cues.

Over the course of 19 experiments, the researchers recorded over 6,000 feeder visits. An analysis of the hummingbirds’ feedings patterns showed that the birds can distinguish ultraviolet plus green from pure ultraviolet or pure green, as well as two different blends of ultraviolet plus red light (one redder, the other less so).

“It was amazing to watch,” said Harold Eyster, a University of British Columbia Ph.D. student and a co-author of the study. “The ultraviolet+green light and green light looked identical to us, but the hummingbirds kept correctly choosing the ultraviolet+green light associated with sugar water. Our experiments enabled us to get a sneak peek into what the world looks like to a hummingbird.”

You might be curious to learn what these additional colors look like. Unfortunately, there is no way to see them — we simply lack the hardware to do so due to the absence of the fourth color cone type.

“The colors that we see in the fields of wildflowers at our study site, the wildflower capital of Colorado, are stunning to us, but just imagine what those flowers look like to birds with that extra sensory dimension,” said co-author David Inouye.

No need to be too jealous, though. The researchers also analyzed a dataset of 3,315 feather and plant colors and found that birds likely perceive many of these colors as non-spectral. However, these non-spectral colors do not stand out relative to other colors that are also visible to humans.

The findings appeared in the journal Proceedings of the National Academy of Sciences.

Scientists discover new hummingbird species and it’s almost extinct already

Remember last week, when we wrote about a newly discovered bird from Africa, and it was already threatened by extinction? Well guess what — it’s happened again. This time researchers working in the Andes describe a previously-unknown hummingbird species which is already under threat, largely due to human activity.

This photo of a previously unknown species of hummingbird led to the discovery of the critically endangered Blue-throated Hillstar. Credit: F. Sornoza.

Hummingbirds are unusual enough, but even among them, hillstars stand out: they live in high-elevation habitats in the Andes mountain range, and as a result, have developed special adaptations to colder climates. Francisco Sornoza of Ecuador’s Instituto Nacional de Biodiversida first observed and photographed this particular hillstar during fieldwork in southwest Ecuador in April 2017.

Francisco had a feeling he’d come across a new species, and he convinced fellow researchers Juan Freile, Elisa Bonaccorso, Jonas Nilsson, and Niels Krabbe, to help. Together, they returned in May to capture specimens and confirm the finding. They dubbed the new species Oreotrochilus cyanolaemus, or the Blue-throated Hillstar, for its iridescent blue throat.

So far, so good — but this is where things start to get nasty. The Blue-throated hillstar is found in a very limited range, only along the bush-lined creeks in an area of about 100 square kilometers (160 square miles). Researchers estimate that at best, there are about 750 individuals, but the real number is likely below 500. Not only is the species threatened by wildfires and grazing, but gold mining also started to chew away at its habitat.

Considering all of this, researchers say that bird meets all the criteria to be considered critically endangered.

“Complete support from national and international conservation agencies is needed in order to save this species,” says coauthor Francisco Sornoza-Molina. “The action plan for the conservation of this bird is creating a network of protected areas along its geographic range.”

This hillstar is also difficult to study because its habitat is very inaccessible. This makes the finding even more exciting — and the conservation even more difficult.

“The hillstar hummingbirds occur in the most rugged, isolated, and inaccessible parts of the Andes, where they roost in caves, forage on the ground, and spend half their lives in hypothermic torpor, so the discovery of a new species in this group is incredibly exciting. This striking discovery confirms that life in the high Andes still holds many secrets to be revealed,” according to the University of New Mexico’s Christopher Witt, a hummingbird expert who wasn’t involved in the study.

“The location is fitting for a new species of hillstar, because it’s a remote, high mountain range that is isolated and is sandwiched between the ranges of two other hillstar species. The authors did a thorough job comparing the new form to its relatives in every respect.”

Journal Reference: “Francisco Sornoza-Molina et al. A striking, critically endangered, new species of hillstar (Trochilidae: Oreotrochilus) from the southwestern Andes of Ecuador”. The Auk. DOI:10.1642/AUK-18-58.1

Panda Solar Plant.

Chinese pandas will slash over 2.74 tons of CO2 emissions in the next 25 yeas — because they’re solar plants

Not yet sold on the idea of solar plants? Even if it was as solar plant… shaped like a panda? Thought so.

Panda Solar Plant.

Image via ledpv.com

It’s an undeniably creative advertising stunt, and it’s actually something which will definitely make Shanxi province of China stand out. The brainchild of Panda Green Energy (formerly known as United Photovoltaics) and the United Nations Development Program, the so-called Panda Power Plant has been under construction since November 2016. To get the panda shapes just right, the group used thin film solar cells for the white and gray face and belly and monocrystalline silicon solar cells to ink in the black areas.

Progress on the plant is going quite well. The first phase/Panda of the project has been completed and is currently churning out some 50 MW of clean, adorable energy into the Chinese grid. Once fully completed, the pandas will have an aggregate capacity of 100 MW and are projected to provide 3.2 billion kWh of electricity over the next 25 years — equivalent to 1.056 million tons of coal or 2.74 million tons of carbon dioxide emissions.

But it’s not merely about energy. The Panda project also aims to invest in the future of the communities it serves, and as such, will come equipped with an activity center to educate local schoolchildren about solar energy and its benefits. For a country left struggling with immense climate issues following what may be the biggest industrialization effort ever seen, projects such as the Panda Power Plant are key to a healthier, cleaner future.

Panda Solar Plants.

A way cuter future, to boot!
Image credits Panda Green Energy Group Limited.

Panda Green Energy revealed that more solar farms are planned over the next 5 years as part of their Panda 100 program. These will be built along the Belt and Roads areas that are part of President Xi Jinping’s economic development strategy.

And yes; they will all be pandas.

Hummingbird

Hummingbirds use their tongues as micropumps to sip nectar

Possibly the most hyper animal, the hummingbird, feeds by darting its thin tongue 20 times per second inside the flower to extract the precious nectar. Previously, biologists thought the nectar was being collected through capillary motion. However, after analyzing 18 different hummingbird species while they fed using high frame rate cameras, a group at University of Connecticut found that the fast flapping birds use a totally different way to suck food: the tongue employed as a tiny pump.

Hummingbird

GIF: YouTube

The idea that hummingbirds use a “wicking” technique to absorb the nectar can be traced back to 1833. Then, a researcher wrote  “the bird curls its forked tongue into a straw shape, and the liquid is drawn up the tube by surface tension.” But Alejandro Rico-Guevara,  a researcher at the University of Connecticut and lead author of the paper, thought the surface tension could keep up with the high licking rate.

Previously, in 2011, Rico-Guevara and colleagues proved that indeed the hummingbirds weren’t using capillary motion to draw nectar. Using high speed cameras, they showed the bird’s tongue is shaped more like a fork than a capillary tube (try putting a really thin tube inside a water vessel, and you’ll see water climbing inside the tube above the water level without any suction).

“When the hummingbird retracts its tongue from the nectar, these fringes close due to the physical forces of surface tension and Laplace pressure, trapping nectar drops in their grips,” says Rico-Guevara. “Due to this transformation of the tongue shape, the tongue tips don’t remain in the tube-shape necessary for capillary action.”

The tip fork-shaped tongue spreads in an explosive-like manner when dipped in the nectar, but that didn’t explain how hummingbird sucked the nectar.

In a new trial, the researchers repeated the experiment with over a dozen species. The birds were filmed with high speed cameras while they sipped from an artificial feeder which mimicked a flower outside and inside.

“What we found is that there is actually a micro-pump, which is transforming the whole tongue shape, and that transformation of the tongue shape is what actually pulls the fluid inside,” Dr. Rico-Guevara said.

“Instead of using vacuum to generate suction—imagine drinking lemonade out of a straw—the system works like a tiny pump, powered by the springiness of the tongue. The bird squashes the tongue flat, and when it springs open, this expansion rapidly pulls the nectar into the grooves in its tongue,” Rico-Guevara writes. “It turns out it’s elastic energy—potential mechanical energy stored by the flattening of the tongue—that lets hummingbirds collect nectar much faster than if they relied on capillarity.”

Besides the empirical evidence, the researchers devised two models: the micro-pump tongue theory and the capillary tub theory. The analysis suggests the micro-pump mode allows the hummingbird to lick faster. In fact, it licks so fast that the snapping movement and pressure generated when the tongue changes shape can suck in fluid.

The findings appeared in Proceedings of Royal Society B.