Thanks to the combination of sensing the earth’s magnetic field through Vision and inside compass which allows them to adjust according to the intensity of the magnet, migratory birds don’t have much trouble finding their way.
That biological device, known as attractionallows birds not only to know which direction to begin their first out-migration but also to know how to return to the nesting site with pinpoint accuracy, often within meters of the original birthing site.
To find out how birds know when to stop, scientists investigated whether birds also use signals from Earth’s magnetic field to more accurately determine their breeding grounds.
Signal can magnetic tilt – the angle of inclination between the earth’s magnetic field and the earth’s surface – or magnetic intensity, the total strength of the earth’s magnetic field.
previous search He proposed a similar idea as a way for birds to return to their desired flight path if a bad weather event had pushed them off course.
The new study used data from 17,799 annular retrievers (typical birds) from 1940 to 2018 to investigate whether Eurasian reed birds (Acrocephalus ssirpaceus), migratory birds that migrate across deserts, using magnetic information to return to their nesting sites.
If these birds did use signals from Earth’s magnetic field to locate their original breeding sites, the researchers believe that annual variations in Earth’s magnetic field should be reflected in gradual changes in the position of the birds’ nesting areas.
“Because the Earth’s magnetic field changes slightly from year to year, values for magnetic parameters that characterize an individual’s birth or reproductive place will be placed in different locations in the following year,” the authors wrote. explain.
“Therefore, if birds use magnetic parameters to determine birth or breeding grounds, we expect that changes in position between years will reflect annual changes in the location of certain magnetic parameters.”
The results of the study show magnetic inclination as the main magnetic indicator of birds when relocating their breeding sites, with certain slope parameters showing a kind of ‘stop sign’.
The author suggests that birds “study” the angle of inclination before leaving their breeding grounds.
“We hypothesized that this corresponds to a trend that acts as a monocoordinate stop sign: birds can remember birth or breeding places using only one-dimensional coordinates, when used in conjunction with compass bearings connecting wintering and breeding grounds.” condition Writer.
Using magnetic predisposition as an initial signal to change their breeding grounds makes sense, according to the authors, as it has the most consistent year-to-year variability compared to other potential magnetic signals. This provides migratory birds with a more reliable sign that they have reached their desired location.
“In addition, the position of other magnetic gradient derivatives moves more with secular variation, making the proposed mechanism relatively robust. The position of the birth site will move as predicted using the slope and slope as a bi-coordinate map, on average, 18.5 km (11.5 mi). ) ) between years; if estimated using density and slope, 20.4 km; and if estimated using density and slope, it is 98.2 km,” condition Writer.
“In contrast, the indicated breeding site using slopes as a stop sign was only 1.22 km between years. We suggest that keeping in mind the breeding ground relative to the most stable pointer and referencing it together with the compass bearing, the proposed strategy minimizes the effects of secular divergence”.
In fact, the scientists found that birds taken for use in studies were closer to locations predicted by the tilt stop sign model compared to birth or breeding sites, suggesting that birds may prioritize biomagnetic tilt coordination signals over breeding sites. .
Overall, it seems that by exploiting a number of biological mechanisms associated with parameters determined by the earth’s magnetic field, migratory birds can successfully navigate and locate the critical environment necessary for their survival.
Publish research in journals science.
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