Hundreds of black birds on the deck of the icebreaker, around the sea, but for some reason they are in no hurry to return to their natural environment. Video from Sakhalin, or rather from the port in Kholmsk, which raises a lot of questions. Some already have answers. As it became known, in these frames - an emergency situation on board the supply vessel. This is where many gray petrels have suddenly landed.
However, the way back was closed for them. As ornithologists explain, the whole point is in the peculiarities of the wing structure, because of which the birds could not take off "from the flat surface of the deck." So, in fact, they were held hostage by the sailors, while interfering with the crew's work. As a result, in order to start unloading at the port, it was decided to try to return the birds to the sea. But there are some remarks to the methods.
Judging by other videos, the uninvited guests were simply swept away with a broom. In the process, according to the local press, some of the birds could have died. The Sakhalin Ministry of Ecology has already stated that the team's behavior is "difficult to call humane." And yet, it is not yet clear whether any damage was actually done to the petrels. Well, why was such a situation even possible and, most importantly, how to act correctly?
So, hundreds of petrels on Monday night landed on the Vitus Bering ship, which was docked in the seaport of Kholmsk in the south of Sakhalin. Birds filled the entire deck. The sailors filmed the invasion of birds. Petrels interfered with loading. However, they could not fly away on their own. As a result, the birds were simply pushed off the deck. How humane such a decision was, the Sakhalin environmental prosecutor's office will figure out. But bird watchers believe that, in fact, there was no other way to drive the birds away.
“Well, I don’t know about 'rude'. But yes, throwing off the deck, this is exactly the way it should be, yes. Exactly. Well, brush it off or toss it into the air, respectively. But, of course, it is better to let sit, if the birds have sat down, they will rest Give them a couple of hours to sit there, if there is an opportunity. They will sit. And then those already rested fly quietly, "explains Sergey Kharitonov, leading researcher at the Center for Bird Ringing at the Institute of Ecology and Evolution. A. N. Severtsov RAS, Doctor of Biological Sciences.
Petrels are actually very good at flying. They spend almost their entire life hovering over the oceans and seas, maneuvering air currents for days. This type of bird does not need dry land as a permanent habitat. They can take short breaks right on the water, and they are able to sleep right in the air!
The petrel wing is an incomprehensible model for technology. Flight aerodynamics are complex and known only in general terms. There are too many subtleties in this matter! During flight, the position of the primary feathers changes, the wing area changes, its wrist and main parts move at different speeds and at different angles.
The wings of petrels are powerful. The same cannot be said about the paws. The real weak link! They are so small and located so close to the tail that birds cannot even stand on them - they have to lean on their wings and chest. Therefore, a petrel can only take off by diving from a great height or catching gusts of wind above the surface of the water.
"From their islands, they also do not take off from the ground. They walk on foot in droves. They nest in burrows. They crawl out of burrows. And this company, large whole streams, are looking for paths on the islands, go to the nearest cliff and, in turn, all are thrown off and take off. "- continues Sergey Kharitonov, leading researcher at the Center for Bird Ringing at the Institute of Ecology and Evolution. A. N. Severtsov RAS, Doctor of Biological Sciences.
Petrel is a type of so-called dynamic hover. They use the features of horizontal air currents over the ocean. The fact is that at the surface of the water and at the height the wind blows at different speeds. So with a seven-point storm, the wind speed at ten meters from the water is 15 m / s, and only 10 m / s at a height of one meter. Considering this factor, the petrel periodically rises and falls, gaining horizontal speed in the faster upper layers of the air and vertical - in the lower layers, due to the higher flight speed than the surrounding air.
And these are not the only tricks these seabirds use. Petrels (as well as albatrosses, gulls and pelicans) constantly balance on the windward side of the wave during flight. And when the wave ends, the bird moves by inertia, looking for a new wave.
Therefore, the sailors did not have much choice but to drive the petrels off the ship. From the deck, without assistance, they would never have taken off.