How Andean condors fly, new research


This November 2018 video says about itself:

Meet the Majestic Andean Condor, one of the world’s largest flying bird, considered a sacred animal for the Incas.

Andean condors are massive birds, among the largest in the world that are able to fly. Because they are so heavy (up to 33 pounds), these birds prefer to live in windy áreas, where they can glide on air currents with little effort.

From Swansea University in Wales:

Experts’ high-flying study reveals secrets of soaring birds

New research has revealed when it comes to flying the largest of birds rely on air currents, not flapping to move around

July 14, 2020

New research has revealed when it comes to flying the largest of birds don’t rely on flapping to move around. Instead they make use of air currents to keep them airborne for hours at a time.

The Andean condor — the world’s heaviest soaring bird which can weigh in at up to 15kg — actually flaps its wings for one per cent of its flight time.

The study is part of a collaboration between Swansea University’s Professor Emily Shepard and Dr Sergio Lambertucci in Argentina, that uses high-tech flight-recorders on Andean condors. These log each and every wingbeat and twist and turn in flight as condors search for food.

The team wanted to find out more about how birds’ flight efforts vary depending on environmental conditions. Their findings will help to improve understanding about large birds’ capacity for soaring and the specific circumstances that make flight costly.

During the study, the researchers discovered that more than 75 per cent of the condors’ flapping was associated with take-off.

However, once in the sky condors can sustain soaring for long periods in a wide range of wind and thermal conditions — one bird managed to clock up five hours without flapping, covering around 172 km or more than 100 miles.

The findings are revealed in a new paper Physical limits of flight performance in the heaviest soaring bird, which has just been published by Proceedings of the National Academy of Sciences.

Dr Hannah Williams, now at the Max Planck Institute for Animal Behaviour, said: “Watching birds from kites to eagles fly, you might wonder if they ever flap.

“This question is important, because by the time birds are as big as condors, theory tells us they are dependent on soaring to get around.

“Our results revealed the amount the birds flapped didn’t change substantially with the weather.

Thousands of Irish children in mass graves


This 15 July 2020 video says about itself:

Six years after from the discovery of 800 babies’ bodies in sewage tanks under a former [Roman Catholic religious] mother and baby home in the Irish town of Tuam, a state commission to investigate what really happened still has yet to report. But Tuam seems to be the tip of the iceberg.

Why carrion crows don’t mate with hooded crows


This is a Czech video about hooded and carrion crows.

By the Ludwig-Maximilians-Universität München in Germany:

Avian speciation: Uniform vs. particolored plumage

July 14, 2020

Although carrion crows and hooded crows are almost indistinguishable genetically, they avoid mating with each other. Researchers from Ludwig-Maximlian-Universitaet (LMU) in Munich have now identified a mutation that appears to contribute to this instance of reproductive isolation.

The carrion crow and the hooded crow are genetically closely related, but they are distinguishable on the basis of the color of their plumage. The carrion crow’s feathers are soot-black, while the hooded crow’s plumage presents a particolored combination of black and light gray. Although crosses between the two forms can produce fertile offspring, the region of overlap between their geographical distributions in Europe is strikingly narrow. For this reason, the two forms have become a popular model for the elucidation of the processes that lead to species divergence. LMU evolutionary biologist Jochen Wolf and his team are studying the factors that contribute to the divergence of the two populations at the molecular level. Genetic analyses have already suggested that differences in the color of the plumage play an important role in limiting the frequency of hybridization between carrion and hooded crows. The scientists have now identified a crucial mutation that affects this character. Their findings appear in the online journal Nature Communications, and imply that all corvid species were originally uniformly black in color.

The ancestral population of crows in Europe began to diverge during the Late Pleistocene, at a time when the onset of glaciation in Central Europe forced the birds to retreat to refuge zones in Iberia and the Balkans. When the climate improved at the end of the last glacial maximum, they were able to recolonize their original habitats. However, during the period of their isolation, the populations in Southwestern and Southeastern Europe had diverged from each other to such an extent that they no longer interbred at the same rate, i.e. became reproductively isolated. In evolutionary terms, the two populations thereafter went their separate ways. The Western European population became the carrion crow, while their counterparts in Eastern Europe gave rise to the hooded crow. The zone in which the two now come into contact (the ‘hybrid zone’) is only 20 to 50 km wide, and in Germany it essentially follows the course of the Elbe River. “Within this narrow zone, there is a low incidence of interbreeding. The progeny of such crosses have plumage of an intermediate color,” Wolf explains. “The fact that this zone is so clearly defined implies that hybrid progeny are subjected to negative selection.”

Wolf wants to understand the genetic basis of this instance of reproductive isolation. In previous work, he and his group had demonstrated that the two populations differ genetically from each other only in segments of their genomes that determine plumage color. Moreover, population genetic studies have strongly suggested that mate selection is indeed based on this very character — the two forms preferentially choose mating partners that closely resemble themselves. These earlier studies were based on the investigation of single-base variation, i.e. differences between individuals at single sites (base-pairs) within the genomic DNA. “However, we have never been able to directly determine the functional effects of such single-base variations on plumage color,” says Matthias Weissensteiner, the lead author of the study. “Even when we find an association between a single-base variant and plumage color, the mutation actually responsible for the color change might be located thousands of base-pairs away.”

To tackle this problem, the researchers have used a technically demanding method to search for interspecific differences that affect longer stretches of DNA. These ‘structural’ variations include deletions, insertions or inversions of sequence blocks. “Up until recently, high-throughput sequencing technologies could only sequence segments of DNA on the order of 100 bp in length, which is not long enough to capture large-scale structural mutations,” says Wolf. “Thanks to the new methods, we can now examine very long stretches of DNA comprising up to 150,000 base pairs.”

The team applied this technology to DNA obtained from about two dozen birds, and searched for structural variations that differentiate carrion crows from hooded crows. The data not only confirmed the results of the single-base analyses, they also uncovered an insertion mutation in a gene which is known to determine plumage color by interacting with a second gene elsewhere in the genome. In addition, phylogenetic analysis of DNA from related species revealed that their common ancestor carried the black variant of the first of these genes. The variant found in the hooded crow represents a new mutation, which first appeared about half a million years ago. “The new color variant seems to be quite attractive, because it was able to establish itself very quickly, and therefore must have been positively selected,” says Wolf. How the variant accomplished this feat is not yet clear. The evidence suggests that it first appeared in the region which now encompasses Iran and Iraq, and there are some indications that the lighter plumage confers a selective advantage in hot regions, because it effectively reflects sunlight. This supports the idea that the mutation might have initially been favored by natural selection. “Once it had reached a certain frequency within the local population, it would have been able to spread because parental imprinting, which enables nestlings to recognize their parents, also causes mature birds to choose mates that resemble their parents in appearance,” Wolf explains. However, other possible scenarios, such as random genetic drift in small populations or the involvement of selfish genes (which promote their own propagation), are also conceivable and have yet to be ruled out.

Saudi regime killing Yemenis with British weapons


Yemeni men offer prayers at the grave of their relative who was killed during the Saudi war on Yemen, at a cemetery in Sanaa, Yemen/>

From daily The Morning Star in Britain, 15 July 2020:

EIGHT children were killed in attacks in Yemen just days before and after [British Conservative] ministers decided to resume arms sales to Saudi Arabia, an investigation by website Declassified claims.

Evidence obtained by Declassified suggests that two airstrikes on July 1 and July 12 were carried out by the Saudi-led coalition.

On July 7, International Trade Secretary Liz Truss announced that she would begin licensing new arms exports to the kingdom.