Extinct North American dire wolves


This 6 September 2018 video from the USA says about itself:

This is not a Game of Thrones fan fiction episode. Dire wolves were real! And thousands of them died in the same spot in California. Their remains have taught us volumes about how they lived, hunted, died and way more about any animal’s sex life than you’d ever want to know.

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Wild turkeys play with American deer


This 15 September 2018 video from North America says about itself:

Turkeys in the wild prove themselves curious and playful with other animals like deer and squirrels.

Prehistoric giant North American dogs


This 28 August 2018 video from the USA says about itself:

The Rise and Fall of the Bone-Crushing Dogs

A huge and diverse subfamily of dogs, the bone-crushers patrolled North America for more than thirty million years, before they disappeared in the not-too-distant past. So what happened to the biggest dogs that ever lived?

Prehistoric horses in North America


This 14 August 2018 video from the USA says about itself:

How Horses Took Over North America (Twice)

The ancestors of modern horses became so successful that they spread all over the world, to Europe, Asia, South America, and Africa. But in their native range of North America, they’ll vanish for 10,000 years. Until another strange mammal brings them back.

The illustration of Equus simplicidens–also known as the Hagerman Horse–is by Roger Hall. You can check out more of Roger’s work here.

Mule deer, cougars studied with satellites


This November 2015 video says about itself:

Top 3: Cougar Facts | Big Cat Week

Learn some little-known facts about mountain lions.

From S.J. & Jessie E. Quinney College of Natural Resources, Utah State University in the USA:

NASA satellites assist states in estimating abundance of key wildlife species

August 9, 2018

Climate and land-use change are shrinking natural wildlife habitats around the world. Yet despite their importance to rural economies and natural ecosystems, remarkably little is known about the geographic distribution of most wild species — especially those that migrate seasonally over large areas. By combining NASA satellite imagery with wildlife surveys conducted by state natural resources agencies, a team of researchers at Utah State University and the University of Maryland, and the U.S. Geological Survey modeled the effects of plant productivity on populations of mule deer and mountain lions. Specifically, they mapped the abundance of both species over a climatically diverse region spanning multiple western states.

These models provide new insights into how differences in climate are transmitted through the food chain, from plants to herbivores and then to predators. Prey and predator abundance both increased with plant productivity, which is governed by precipitation and temperature. Conversely, animals responded to decreases in food availability by moving and foraging over larger areas, which could lead to increased conflict with humans. David Stoner, lead author of the study, “Climatically driven changes in primary production propagate through trophic levels” published today in the journal Global Change Biology, remarked that, “We expected to see that satellite measurements of plant productivity would explain the abundance of deer. However, we were surprised to see how closely the maps of productivity also predicted the distribution of the mountain lion, their major predator.”

The study also reveals a disruption in the way scientists study the biosphere. Joseph Sexton, Chief Scientist of terraPulse, Inc. and a coauthor on the study, described the changing technology, “Up until about a decade ago, we were limited to analyzing landscapes through highly simplified maps representing a single point in time. This just doesn’t work in regions experiencing rapid economic or environmental change — the map is irrelevant by the time it’s finished.” Now, given developments in machine learning, “big data” computation, and the “cloud”, ecologists and other scientists are studying large, dynamic ecosystems in ever-increasing detail and resolution. “We’re now mining global archives of satellite imagery spanning nearly forty years, we’re updating our maps in pace with ecosystem changes, and we’re getting that information out to government agencies and private land managers working in the field.”

The authors predict that, by enabling land managers to monitor rangeland and agricultural productivity, forest loss and regrowth, urban growth, and the dynamics of wildlife habitat, this expanding stream of information will help humanity adapt to climate and other environmental changes. Stoner noted, “State wildlife agencies are tasked with estimating animal abundance in remote and rugged habitats, which is difficult and expensive. Integration of satellite imagery can help establish baseline population estimates, monitor environmental conditions, and identify populations at risk to climate and land-use change.”

Where are American crows in winter?


This June 2018 video is called 5 Reasons To Like Crows (American Crow).

From the American Ornithological Society Publications Office in the USA:

Where do crows go in winter?

August 8, 2018

“Partial migration” — where some individuals within a population migrate and some don’t — is common among birds and is speculated to be a step on the evolutionary path to complete, long-distance migration, but scientists know very little about how it actually works. A new study from The Auk: Ornithological Advances tracks where American Crows go during the winter and shows that while individuals are consistent in whether they migrate or stay put, partial migration might give them enough flexibility to adapt to changing environmental conditions.

Hamilton College’s Andrea Townsend and her colleagues captured crows in large winter flocks in Utica, New York, and Davis, California, fitting them with satellite transmitters to track their movements and collecting blood and feather samples. Their data show that 73% of western crows and 86% of eastern crows migrated at least some distance to breed, with an average journey of around 500 kilometers. Birds returned faithfully to the same breeding territory each year, and whether or not individuals migrated was consistent from one year to the next — they didn’t switch strategies depending on environmental conditions. However, they were flexible in where they spent the winter.

This information can serve as an important baseline for tracking how crows’ migratory behavior is affected by factors including climate change and urbanization. Urban “heat islands,” as well as general warming trends, could lead more birds to shorten their migration and spend the winter closer to their breeding territory. “If you live in a place, usually a city, with a huge winter flock of crows, you are seeing migratory birds that came south for the winter as well as your local, year-round crows”, says Townsend. “Personally, I find the sight of an 8000-crow roost exhilarating, but if they or their feces are driving you crazy, you can at least take comfort in knowing that most of them will disappear in early March.”

“It is surprising how much remains unknown about the seasonal movements of most partial migrant species, and this is especially true for variability among populations,” adds the Smithsonian Migratory Bird Center’s Emily Cohen, an expert on migration patterns who was not involved with the study. “This kind of information about populations-specific annual movements is not trivial to collect, but is fundamental to understanding most aspects of the evolution and ecology of species.”

American golden-crowned sparrows, new study


This video from North America says about itself:

Golden-crowned Sparrow singing

Golden-crowned Sparrows are common winter birds in weedy fields along the Pacific Coast. In spring they migrate to northern Alaska and Canada, where they sing a sweetly whistled song from spruces and other low perches.

From the University of California – Santa Cruz in the USA:

Among golden-crowned sparrows, a false crown only fools strangers

Researchers can change dominance relationships between birds by altering the colors on their heads, but only if the birds don’t already know each other

July 25, 2018

Scientists studying winter flocks of golden-crowned sparrows at the UC Santa Cruz Arboretum have discovered surprisingly complex social behavior in these small migratory birds. A new study reveals that the sparrows have different ways to assess dominance status depending on whether the interaction is with a familiar bird or a stranger.

Previous studies by the UC Santa Cruz researchers showed that the patches of yellow and black plumage on the birds’ heads serve as “badges of status”, signals that correlate with fighting ability and allow birds to figure out who is dominant without having to fight. Birds with bold crown coloring are dominant over those with duller crown colors, regardless of whether the bold colors are natural or painted on by the researchers. Those were the findings of two studies published in 2011 and 2013, in which the researchers staged confrontations by placing two birds captured in different locations together in an aviary.

“To show that birds are using badges of status, you have to pit birds against each other that have never met to make sure they do not have prior information about fighting ability”, explained Bruce Lyon, professor of ecology and evolutionary biology at UC Santa Cruz.

Lyon’s lab has now been studying the Arboretum’s golden-crowned sparrows for 15 years. The plumage studies have been led by Alexis Chaine, a former graduate student in the lab who is now at the National Center for Scientific Research (CNRS) station in Moulis, France.

In their latest study, published July 25 in Ecology Letters, the researchers found that badges of status don’t matter to golden-crowned sparrows that already know each other. The researchers can paint bold colors on the crown of a dull-colored sparrow and it will still be as subordinate to other birds in its flock as it was before the plumage makeover.

“Plumage manipulations do not fool birds that know each other”, Lyon said, noting that the researchers decided to return to the plumage manipulation studies after subsequent studies revealed close affiliations between birds in winter flocks.

“The idea with badges of status is that they will be useful to animals that live in large or fluid social groups where they wouldn’t be able to recognize and remember the fighting abilities of all the opponents they might encounter”, he said. “We realized that the previous experiments we did with unfamiliar birds did not represent the social context in which these sparrows spend most of their time in winter.”

The new findings show that golden-crowned sparrows use crown plumage to resolve dominance status with strangers, while social recognition governs dominance relations with familiar birds. The researchers have found that all yearlings have dull crown colors, but the plumage changes and becomes fixed in a bird’s second year. At that point, there is tremendous variation in the crown plumage of different birds, but an individual’s coloring remains the same for the rest of its life.

“Some of that is likely due to genetic variation, but it could also be affected by early experiences or developmental conditions. At this point, we just don’t know,” Lyon said.

An understanding of the social networks of wintering golden-crowned sparrows emerged from work led by Daizaburo Shizuka, another former graduate student in Lyon’s lab who is now at the University of Nebraska in Lincoln. A study published in 2014 showed that the same birds come together in the same locations year after year, forming short-term feeding flocks that are subsets of distinct social communities with well-defined home ranges. They do this after migrating thousands of miles from their summer breeding grounds in northern Canada and Alaska where, instead of forming flocks, they fiercely defended small individual territories around nesting sites.

“The birds within each community return year after year to hang out with the same friends. It’s not just that they overlap on the same turf. They appear to form very close lifelong winter relationships”, Lyon said. “Normally, such close affiliations are driven by kinship, but our genetic study showed that kinship is not a factor in these communities. We suspect that these friendships are driven by the benefits of cooperation.”

By forming flocks with familiar birds, golden-crowned sparrows are able to spend less energy on aggressive interactions and more time feeding, improving their chances of surviving through the winter. In their experiments, the researchers found that sparrows showed less aggression and spent more time feeding when paired with a familiar flockmate than when paired with a stranger.

Traditionally, researchers have looked for either badges of status or individual recognition as the mechanism for resolving dominance status in a given species, but not both. The system seen in golden-crowned sparrows, with context-dependent use of both mechanisms, may be more common than is currently recognized, Lyon said.

The roles of badges of status and individual recognition in dominance behavior raise many questions that have led to long-running debates among evolutionary biologists, he said. A key question for badges of status has been, what keeps them honest? The whole system would break down if, in the case of golden-crowned sparrows, crown patches did not correlate with fighting ability, allowing a “cheater” with bold crown coloring but poor fighting ability to dominate the seed pile.

In their new paper, however, the researchers suggest that the use of both badges of status and individual recognition in different contexts can diminish the value of a dishonest badge, because interactions within a social group no longer rely only on badges of status. “Badges of status might be used to settle dominance when a bird initially joins a group, but recognition subsequently modulates interactions,” they wrote.

In addition to Chaine, Lyon, and Shizuka, the coauthors of the new paper include Theadora Block and Lynn Zhang, both of whom worked on the study as UCSC undergraduates (Block is now a graduate student in Lyon’s lab). Lyon said dozens of undergraduates have been involved over the years in his lab’s research on golden-crowned sparrows at the UC Santa Cruz Arboretum. In fact, the long-running research program began as a project for undergraduates in a class Lyon was teaching.

“It started out as a side project in our lab, and now it may be one of the most complete studies that have been done of winter flocks of migratory birds,” Lyon said. “We still have a lot of interesting questions to investigate.”

This work was funded by UC Santa Cruz, CNRS, and the National Research Agency of France (ANR).