Intelligence helping Costa Rican hummingbirds

This video says about itself:

7 February 2018

New experiments show that dominant male Long-billed Hermits have better spatial memories and sing more consistent songs than less successful males, according to research published in the journal Scientific Reports.

From the Cornell Lab of Ornithology in the USA today:

It’s Brains Over Brawn for Male Long-billed Hermits Seeking Mates

In the glitzy world of hummingbirds, one species seems to profit more from mental prowess than physical flamboyance. For male Long-billed Hermits in Costa Rica, having a good spatial memory is a key factor in winning prime display spots. See the full story here.


Hummingbirds’ high-frequency sounds, new research

This 2015 video is called Black Jacobin hummingbird | Florisuga fusca at the feeder in slow motion.

From ScienceDaily:

These tropical hummingbirds make cricket-like sounds other birds can’t hear

March 5, 2018

Researchers reporting in Current Biology on March 5 have found that a tropical species of hummingbird called a black jacobin makes vocal sounds with an unusually high-frequency pitch that falls outside birds’ normal hearing range. It’s not yet clear whether the hummingbirds can even hear themselves, the researchers say.

“These vocalizations are fast and high pitched, and in fact they do not sound at all like your typical bird sound”, says Claudio Mello from Oregon Health and Science University. “They sound more like an insect, such as a cricket, or like a tree frog.”

Mello and his colleagues stumbled onto the discovery quite by accident while studying many species of hummingbirds in the forested mountains of Eastern Brazil.

“We heard prominent high-pitch sounds that sounded perhaps like a cricket or a tree frog,” Mello says. “But then we noticed that the sounds were actually coming from these black hummingbirds.”

The researchers thought the vocalizations had to be at an unusually high pitch, but they didn’t have the equipment needed to measure it. So, on a later trip, they took detectors with them that are normally used to pick up the high-frequency sounds of bats. They confirmed that the detectors picked up on these unusual hummingbird sounds.

More recently, they made recordings of the sounds using special recording equipment designed to study bat calls. The recordings showed that the sounds were quite remarkable, having a high degree of complexity and being produced at high frequency, including components in the ultrasonic range that humans can’t hear.

The discovery suggests that either black jacobins hear sounds other birds can’t or that the birds produce sounds they can’t even hear. The researchers speculate that the birds might rely on the unusual calls as a private channel of communication. That could be especially useful given that black jacobins live among a diverse group of bird species, including 40 other species of hummingbirds.

“It seems more reasonable to assume they do hear the sounds they make, but we have not yet examined whether this is true,” Mello says.

Bird hearing generally has to be tested in a lab, either by recording from the brains of anesthetized birds or by watching how birds respond to sounds. Those studies aren’t amenable to studying hummingbirds in the wild.

The findings suggest that the hummingbirds must have an unusual vocal organ, the syrinx, to produce these sounds. “They would need to vibrate very quickly and likely have a special composition, which may be different from other birds”, he says.

Mello says it would now be interesting to study the black jacobins’ inner ears to see how or whether they differ from those of other birds. And, if it turns out that the birds can’t hear themselves? Well, that would raise a whole host of other intriguing questions.

We found that larger hummingbirds are more fuel efficient than smaller species, and this may have to do with how smaller hummingbirds need to beat their wings more rapidly than larger species: here.

How hummingbirds fly, new research

This video says about itself:

What makes hummingbirds such agile flyers?

8 February 2018

Looking over hundreds of flight recordings, researchers gained new insight into what makes hummingbirds so good at fast, agile flight.

Read more here.

Mites on hummingbirds’ tails, new study

This 2017 video from the USA is called Stunning up-close footage of an Anna’s Hummingbird.

From PLOS:

Majority of Anna’s hummingbirds may have feather mites on their tail feathers

Tabletop scanning electron microscopy enabled analysis of P. huitzilopochtlii distribution in situ

February 14, 2018

The majority of Californian Anna’s Hummingbirds appear to have P. huitzilopochtlii feather mites on their tail flight feathers, according to a study published February 14, 2018 in the open-access journal PLOS ONE by Youki Yamasaki from Washington State University, U.S., and colleagues.

Hummingbirds are known to host a diversity of feather mites, but this relationship is not well-understood. In particular, mite distribution in situ has not been previously studied. The authors of the present study examined 753 hummingbirds of five species from urban locations in California: Anna’s, Allen’s, Black-chinned, Calliope and Rufous Hummingbirds. They documented the presence of the feather mite Proctophyllodes huitzilopochtlii on tail flight feathers.

The researchers found that feather mites were present on the tail flight feathers of nearly 60 percent of Anna’s hummingbirds, but less than 10 percent of the other species. Across all the species, the mite was more prevalent on the tail feathers of males (44.9 percent) than on those of females (36.2 percent), possibly because of the nesting habits of females.

The authors used tabletop scanning electron microscopy to analyze individual feathers, building a detailed 3D picture of the distribution of live mites in situ. They found that there tended to be more mites on the hummingbirds’ outer tail feathers than inner, and saw that mites often nestled between the barbs of individual feathers, sometimes in high numbers.

The authors state that their study provides the first prevalence and distribution information for these feather mites on both Anna’s and Black-chinned Hummingbirds. This is especially important given that Anna’s Hummingbirds co-reside seasonally with other hummingbird species, with the potential for spread of mites.

Co-author Lisa Tell summarizes: “This study was exciting because not only were we able to document the presence of a mite on feathers from two species of hummingbirds found in California, but we were also able to examine the positioning of live feather mites in situ with electron microscopy that is portable enough to use in the field.”

Hummingbirds’ flying and evolution, new research

This video is called Nat Geo Wild: Hummingbirds, Jewelled Messengers.

From the University of British Columbia in Canada:

Evolution — and skill — help hefty hummingbirds stay spry

Larger species of hummingbirds, despite their increased mass, are able to adapt to outmaneuver smaller species

February 8, 2018

Evolved differences in muscle power and wing size — along with a touch of skill — govern hummingbirds’ inflight agility, according to new research in Science.

The findings by University of British Columbia biologists show that larger species of hummingbirds, despite their increased mass, are able to adapt to outmaneuver smaller species.

“Studies of bats, birds and other animals show that increases in body mass can have a detrimental effect on many aspects of flight,” says Roslyn Dakin, co-lead author on the study.

“But with hummingbirds, the correlated evolution of increased wing size and muscle mass helps larger species compensate for their greater body masses.”

Dakin, study co-lead Paolo Segre and senior author Douglas Altshuler used sophisticated video capture and a novel geometrical framework to determine how maneuverability relates to differences in physiology — notoriously difficult relationships to quantify.

They found that acceleration is primarily driven by a bird’s muscle capacity, whereas maneuvers involving rotations are driven primarily by wing size. But skill also plays a role.

“The hummingbirds tend to play to their strengths, especially with complex moves”, says Altshuler. “For example, species that have the ability to power through turns tend to use more arcing trajectories, and they shy away from performing turns in which they decelerate to turn on a dime.”

The researchers captured over 200 individual hummingbirds from 25 Central and South American species. Computer vision technology developed by co-author Andrew Straw at the University of Freiburg in Germany enabled the researchers to record inflight maneuvers with precision.

“We recorded over 330,000 maneuvers, including many repeated maneuvers for each bird”, says Segre, now a postdoctoral researcher at Stanford University.

“Capturing that much data was a challenge. Our first field site was at a biological reserve deep in the Peruvian Amazon, an area with many species of hummingbirds, but only accessible by boat. We ran our computers and cameras using solar panels and generators in a thatched hut with strategically placed rain buckets!”

Hummingbirds vary greatly in body mass and wing shape — and many species have evolved to perform at high elevation where the air density is low. That variety offers researchers a great opportunity to study how traits relate to agility in flight, says Dakin.

“There are a lot of questions we can look into now. How do these differences impact their ability to survive and find mates? If maneuverability is an advantage to some species, how do others get by with less agility? What is it about their lifestyle that differs?”

Texas hummingbirds 2017 highlights video

This video from the USA says about itself:

Jewels Of The Davis Mountains: 2017 West Texas Hummingbird Cam Highlights

14 December 2017

From North America’s smallest breeding bird—the Calliope Hummingbird—to the comparably colossal Blue-throated Hummingbird, relive the rich diversity of tiny fliers (and more) that visited the West Texas hummingbird cam in 2017.

The West Texas Hummingbird Feeder Cam is nestled in the mountains outside Fort Davis, Texas, at an elevation of over 6200 feet. This site hosts a total of 24 Perky Pet Grand Master hummingbird feeders, and during peak migration can attract hundreds of hummingbirds from a dozen species that are migrating through the arid mountains.

How hummingbirds hover

This video says about itself:

Hummingbirds have massive hearts to power their hovering flight

1 December 2017

Birds that hover in front of flowers have huge hearts to power their energy-intensive flight, and even birds that glide effortlessly need fairly big hearts to keep it up. Read more here.