When we discuss the biodiversity issue, the extinction of species, or concepts like the sixth great extinction, which experts claim we are currently experiencing, it can be challenging to assess the situation from the viewpoint of the average person. Behind all these complicated terminologies, there are a hundred minor tragedies: lost lands, individuals missing, and rare species whose genetic heritage is no longer available to us. The loss of biodiversity includes three aspects: the destruction of ecosystems, the extinction of specific species, and the loss of genetic diversity, which will result in future impoverishment.
In the late nineteenth century, scientists and the general public were both shocked by the loss of passenger pigeons (Ectopistes migratorius). A lot of people were prompted to wonder how a bird that was so abundant that it had flocks that literally “darkened the sky for days” as they soared by, could have vanished in just a few short decades. In fact, mega-flocks with hundreds of millions of birds were typical until the 1870s, and stores in big cities sold passenger pigeon flesh for pennies. The last member of a species is referred to as an “endling,” which is a lone individual doomed to extinction because they are incapable of reproducing. In the past century, there have been a few of these endlings named specimens that carried the final traces of a species that was certain to go extinct.
The last pigeon to arrive
The extinction of one of the most remarkable birds in the world, the American migratory pigeon (Ectopistes migratorius), whose massive flocks of millions of copies astounded the first Europeans who visited America from the North, occurred in September 1914.
In 1759, the Finnish-Swedish naturalist Pehr Kalm wrote:
“Incredible numbers of these pigeons came into Pennsylvania and New Jersey in the spring of 1749 from the north. They flew so closely together that they created a cloud three to four miles long and more than a mile wide. As a result, the sky and the Sun were darkened, and the amount of sunshine was noticeably reduced in their shadow. It was challenging to identify an empty branch among the tiny and large trees for a distance of up to seven kilometers due to their dense population. When hurled into trees, their weight was so great that less firmly rooted trees were overturned by the burden in addition to having thick branches pulled off by the roots. Excrement was piled up on the ground beneath the trees where they had spent the night.
A few decades before, the passenger pigeon was very abundant. The largest flock ever seen was three hundred miles long and a mile wide, and it was seen in southern Ontario in 1866. It is estimated that it contained more than three and a half billion birds or a significant portion of the species’ total population and that it caused a noticeable drop in temperature during the fourteen hours that it was visible. Another flock took three days to pass, according to a description made by naturalist John James Audubon in 1830.
“I dismounted, sat on an eminence, and began to mark each passing flock with a pencil point.”
I rose up after a short time, finding the task I had begun impractical, as the birds passed by in innumerable flocks, and counted the points I had entered, discovering that I had made 163 in twenty one minutes. I proceeded on my journey, discovering more as I went. The air was literally full of pigeons, the midday light was covered as if by an eclipse, droppings showered down like flakes of ice, and the constant rustling of wings soothed my senses… I arrived at Louisville, fifty-five miles from Hardensburgh, before dusk. The pigeons flew by without lowering their numbers, and they did so for three days”.
However, those birds were persecuted by the same individuals who poetically described their great numbers. Due to its abundance, they believed it to be an endless supply. However, after a few decades, they realized that widespread and unrelenting harassment in their habitats to mate and rest was erasing that natural beauty from the face of the planet. Pigeons were incredibly simple to trap due to their tendency to congregate in colonies. It was already too late for the settlers to stop the overwhelming persecution from destroying them.
Due to the destruction they had wrought, the inhabitants were never able to recover and vanished completely. The endling passenger pigeons spent their final years alone and without the chance of procreation, preserved as a reminder of wild America and a living example of the results of human greed and foolishness. In Ohio in March 1900, a young kid killed the last known wild passenger pigeon. A formal declaration of the extinction of the species was made on September 1, 1914, when the last, a pigeon by the name of Martha, passed away at the Cincinnati Zoo at the very advanced age of 17 to 29. The world’s most populous bird’s astonishing demise occurred in front of a large portion of North American civilization, who witnessed it unfold. It happened over such a little period that it became one of the most widely covered bird extinctions in history. Despite the fact that it has been 108 years since the last migratory pigeon perished and that we are aware of the root reasons for the avian fauna’s demise, the decline of birds is still a daily occurrence in modern times.
A worldwide decline in migratory birds
Every year, over 50,000 million birds take to the skies in search of land to eat and procreate.
Certain merely leave the mountains in search of milder winters in the lowlands, but others travel enormous distances, reaching tens of thousands of kilometers in some cases. Interestingly, when compared to birds that live in certain environments, it is this group of migratory birds that is most at risk of extinction, but why?
Researchers from UEA’s School of Environmental Sciences used remote sensing data and expert opinion to map 16 anthropogenic risks to migrating birds across Europe, Africa, and the Middle East, including the first spatially explicit pan-continental evaluation of relative hunting pressure. According to the study published in the journal “Global ecology and biogeography,” species that migrate to areas with more human infrastructure, roads, buildings, power lines, wind turbines as well as higher population densities and hunting levels have experienced the greatest population declines. These losses in bird populations are also brought about by agricultural intensification, habitat loss, degradation, fragmentation, invasive species, and climate change. The authors stress the significance of spatially explicit approaches to estimating anthropogenic drivers of population decreases. Composite risk maps are an invaluable tool for analyzing the regional distribution of human caused risks to migratory birds and enabling focused conservation measures.
Figure 1. The ability of certain wild species to adapt to the numerous challenges provided by humans in the course of our unrelenting growth is just as important to their existence as the conditions of the natural habitat in which they reside. It can be difficult for migratory birds to navigate around human infrastructures like wind turbines and buildings. Credits: American Public Power Association from Unsplash
The keys to the disappearance
Human activity has had such an impact on the world that some scientists have advocated designating the advent of a new geological period, which they have dubbed the Anthropocene. The Anthropocene period, according to the researchers who proposed it, began in the 1950s. However, the impact of the arrival of the human species may have begun far earlier than in the last century, as in the case of the pigeon Ectopistes migratorius. The migrating birds encounter humans as their greatest concern due to their colonial lifestyle, the strategy of vast numbers, and the requirement for large breeding places. The reality is that human interests which include the need to destroy forests for agriculture and the growth of urban sprawl are inimical to those of birds, which depend on expansive forests to exist.
The Smithsonian Institution, which houses the body of Martha, the last of the passenger pigeons, attempts to promote optimistic thinking about this enormous ecological drama. “The passenger pigeon extinction only had one positive outcome: it sparked public awareness of the necessity for strict conservation legislation. Many additional bird and wildlife species have been spared as a result of the following adoption of these rules and the ongoing investigation by scientists and naturalists over the past few decades.
Figure 2. One tragic example of what happens when human interests clash with those of nature is the extermination of the American passenger pigeon. A picture of Martha, the final passenger pigeon specimen and officially declared extinct in 1914. Credits: Smithsonian Institution, National Museum of Natural History
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