Spotted nutcracker feeding in Sweden, video


This video is about a spotted nutcracker feeding in Sweden.

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Anna’s, Rivoli’s hummingbirds in Texas, USA


This video from Texas in the USA says about itself:

What’s In A Name: Anna’s and Rivoli’s Hummingbirds – Sept. 12, 2019

Did you know the names of the Anna’s and Rivoli’s Hummingbird are connected? When these species were described in 1829 by French naturalist René Primevère Lesson, he named these dazzling hummers in honor of the Duke of Rivoli and his duchess, Anna de Belle Masséna. Watch a flashy male Anna’s alight on the back right feeder port before a male Rivoli’s steals the spotlight on the back left of the feeder.

Watch live at http://allaboutbirds.org/texashummers for more information about hummingbirds and highlights from the feeders.

Yellow-billed loons in love, video


This video from the Cornell Lab of Ornithology in the USA says about itself:

The Yellow-billed Loon is the largest and most spectacular of the world’s five loon species. It breeds around the globe in arctic and sub-arctic tundra lakes and is the northern counterpart to the Common Loon.

Watch this rare video shot by The Lab’s Gerrit Vyn of a mated pair calling and foraging just after arriving on the partially frozen breeding grounds in Chukotka, Russia.

Central America critical for migrating birds


This January 2015 video says about itself:

US Bird Count Shows Climate Change Affecting Migration Patterns

Thousands of birdwatchers in the United States, Canada, Latin America and the Caribbean were out in force from mid-December to the beginning of January (December 14-January 5) counting birds. They took part in the 115th “Christmas Bird Count”, sponsored by the National Audubon Society, a U.S. bird conservation organization. Data collected from the annual event is helping scientists understand how environmental changes affect birds. VOA’s Deborah Block joined a group of birdwatchers in the wetlands at Mount Vernon, Virginia -the famous home of the first U.S. president, George Washington.

From Oxford University Press USA:

Conservation of a Central American region is critical for migrating birds

September 12, 2019

Many of North America’s migratory birds are declining, but the mysteries about when and how birds migrate must to be solved to effectively protect them. A new paper in The Auk: Ornithological Advances, published by Oxford University Press, identifies a previously overlooked area that is critical for conservation: the region between southern Mexico and Guatemala where songbirds fuel up for a grueling flight across the Gulf of Mexico.

Migration is a dangerous time for birds, especially during flights over large bodies of water. Many birds migrate directly across the Gulf of Mexico, requiring over 600 miles of sustained flight. The details of how the survivors manage this feat of endurance have been murky, especially for species like warblers, whose small size prevented researchers from tracking their full migration routes until recently.

Researchers used light-weight geolocators to identify migration strategies for the vulnerable and declining Golden-winged Warbler, finding 80% of individuals spent a week in southern Mexico and Guatemala to feed and build up reserves for the flight over the Gulf of Mexico in spring migration. The importance of this stopover region was previously unknown for this species, and it needs conservation given the rapid conversion of natural habitats to pasture and farmland.

While most Golden-winged Warblers stopped in this region, not all did. Some that overwintered in northern Central America were able to make the trans-Gulf flight directly from their overwintering grounds without the stopover. “This is an important finding,” says Dr. Ruth Bennett of the Smithsonian Migratory Bird Center, “because birds that migrated directly across the Gulf were able to shave a week off their total migration time. These birds may experience a selective advantage in the spring.” That is because male Golden-winged Warblers race north in spring migration to establish breeding territories. Results from the study suggest the spring period requires more energy and poses a greater risk of predation and starvation, while fall migration allows for more flexibility to minimize energy costs and avoid risks.

“The variation we describe in migration routes and stopovers is encouraging,” says Bennett. “Variation helps buffer a population from local changes in environmental conditions.” Now that authors have identified where and when Golden-winged Warblers prepare for migration, they can start identifying the habitats that best allow birds to fuel up and successfully cross the Gulf of Mexico. This study provides a critical piece of the larger puzzle about where, when, and how to best protect the declining Golden-winged Warbler and other North American migratory birds.

Hunting marsh harrier and kingfisher


This March 2019 Dutch video is about the Sophiapolder island in the Netherlands, which recently became a freshwater tidal nature reserve.

After our visit to the Crezéepolder nature reserve, we went there on 8 September 2019.

As the ferry arrived at the island, a Cetti’s warbler sang.

A kingfisher sitting on a branch above the water.

Shelducks swimming with their ducklings.

A peacock butterfly on a flower along the footpath.

A northern lapwing sits down on the wooden walkway across the water.

Then, a female marsh harrier tries to catch a duck. For a few seconds she grabs it, but has to drop it. Then, she goes to the shore, feeding on a dead animal there. A carrion crow next to her tries to get some of the food.

Why birds migrate at night


This video says about itself:

A massive and very impressive songbird migration night with thousands of birds crossing the Baltic Sea and resting on a research vessel in October 2015.

This video is the sequel.

From Southern Methodist University in the USA:

Why do birds migrate at night?

September 12, 2019

Summary: Researchers found migratory birds maximize how much light they get from their environment, so they can migrate even at night.

It was a puzzle about birds.

Migratory birds are known to rely on Earth’s magnetic field to help them navigate the globe. And it was suspected that a protein called cryptochrome, which is sensitive to blue light, was making it possible for birds to do this.

Yet many of these animals are also known to migrate at night when there isn’t much light available. So it wasn’t clear how cryptochrome would function under these conditions in birds.

A new study led by UT Southwestern Medical Center in collaboration with SMU (Southern Methodist University), though, may have figured out the answer to that puzzle.

Researchers found that cryptochromes from migratory birds have evolved a mechanism that enhances their ability to respond to light, which can enable them to sense and respond to magnetic fields.

“We were able to show that the protein cryptochrome is extremely efficient at collecting and responding to low levels of light,” said SMU chemist Brian D. Zoltowski, who was one of the lead authors of a new study on the findings. “The result of this research is that we now understand how vertebrate cryptochromes can respond to very low light intensities and function under night time conditions.”

The study was published in the journal PNAS in September.

Cryptochromes are found in both plants and animals and are responsible for circadian rhythms in various species. In birds, scientists were specifically focused on learning more about an unusual eye protein called CRY4, which is part of a class of cryptochromes.

The lab of Joseph Takahashi, a circadian rhythms expert at UT Southwestern Medical Center, worked with other UT Southwestern scientists to purify and solve the crystal structure of the protein — the first atomic structure of a photoactive cryptochrome molecule from a vertebrate. The lab of Brian Zoltowski, an expert in blue-light photoreceptors, studied the efficiency of the light-driven reactions — identifying a pathway unique to CRY4 proteins that facilitates function under low light conditions.

“Although in plants and insects, cryptochromes are known to be photoactive, which means they react to sunlight. Among vertebrates much less is known, and the majority of vertebrate cryptochromes do not appear to be photoactive,” said Takahashi, chairman of neuroscience at UT Southwestern and an investigator with Howard Hughes Medical Institute. “This photosensitivity and the possibility that CRY4 is affected by the magnetic field make this specific cryptochrome a very interesting molecule.”

Researchers took a sample of the CRY4 from a pigeon and grew crystals of the protein. They then exposed the crystals to x-rays, making it possible for them to map out the location of all the atoms in the protein.

And while pigeons are not night-migratory songbirds, the sequences of their CRY4 proteins are very similar, the study noted.

“These structures allow us to visualize at the atomic scale how these proteins function and understand how they may use blue-light to sense magnetic fields,” said Zoltowski, associate professor of chemistry at SMU’s Dedman College of Humanities & Sciences. “The new structures also provide the first atomic level detail of how these proteins work, opening the door for more detailed studies on cryptochromes in migratory organisms.”

In the study, researchers discovered unusual changes to key regions of the protein structure that can enhance their ability to collect light from their environment.

“Cryptochromes work by absorbing a photon of light, which causes an electron to move through a sequence of amino acids. These amino acids typically consist of a chain of 3 or 4 sites that act as a wire that electrons can flow through,” explained Zoltowski. “But in pigeons, it was identified that this chain may be extended to contain 5 sites.”

This mutation of the electron chain in pigeons makes cryptochrome less dependent on a bird’s environment having a lot of light for the protein to be activated.

“Birds have evolved a mechanism to enhance the efficiency. So even when there is very little light around, they have enough signal generated to migrate,” Zoltowski said.