Birds are attracted to the scent of grass and leafy vegetables

Stork prey likes to live in tall grass. Foraging is easier for birds when the meadows are freshly cut. Credits: MPI of Animal Behavior / C. Ziegler

The sharp eyes of an eagle, the abnormal hearing of an owl — the bird’s eyes and ears were optimally adapted to their living conditions in order to succeed in finding food. So far, the scent sensation has played a fairly subordinate role. When the meadows are freshly cut, storks often appear in search of snails and frogs.Max Planck Institute Researcher Animal behavior The Maxplank Institute of Chemistry in Radolfzel and Mainz is now studying bird behavior and found that storks are attracted to the smell of cut grass. Only storks that were leeward and therefore able to perceive odors responded to mowing. Scientists also sprayed the meadows with a spray of green leaf scent released during mowing. Storks also appeared here. This indicates that the white stork is using the sense of smell to search for food, suggesting that the sense of smell may play a greater role in other birds than previously thought.

It is a well-known sight for farmers around Lake Constance. Storks often appear next to tractors out of nowhere as they begin to mow the meadows. White storks live in the moist areas around the lake and feed on snails, frogs and small rodents that evacuate to high meadows. Small animals can easily become prey when these meadows are mowed. However, storks do not always appear when mowing. Until now, it was not known how storks would find abundant food sources.

Previously, birds were thought to be primarily dependent on the eyes and ears. Smell sensation.. “Birds simply didn’t have a real nose and were simply supposed to have a bad sense of smell,” says Martin Wickelski, director of the Max Planck Institute for Animal Behavior. “Still, they have a very large olfactory bulb in their brains and a lot of scented receptor molecules.” Therefore, birds have the best prerequisites for a thin nose.

Smell test

Wikelski has spent many years observing storks and studying locomotion behavior. Williams had an idea when he told his colleague Jonathan Williams about the mysterious reaction of storks to the mowed meadows. Williams is studying volatile organic compounds and their effects on humans and the environment at the Maxplank Institute of Chemistry in Mainz, Germany. “My guess is that storks were reacting to the strong scent of freshly cut storks. grass“Williams says. This typical odor is produced by the so-called green leaf odorant and is composed of only three different molecules. “These are also added to the perfume, giving them a fresh“ green ”note,” explains Williams. ..

Stork's thin nose

The first stork often appears shortly after mowing begins. The smell of freshly cut grass fascinates them. Credits: MPI of Animal Behavior / C. Ziegler

Researchers now wanted to know if the scent sensation actually led to freshly cut meadows for storks. To do this, they monitored the movement of birds from aircraft and via GPS sensors on tagged animals. “First, we needed to eliminate the possibility of storks hearing the tractor and seeing the mowing process,” says Wikelski. Therefore, they included only storks that were more than 600 meters away from the mowed pasture and were not in direct visual contact. Researchers also confirmed that the behavior of birds of the same species and other birds did not warn storks about the mowing process.

When weeding began, only the storks downwind flew to the meadow in question. The same species, which was upwind and therefore unable to perceive the scent of grass, did not respond. To test whether only the smell of the cut grass attracts storks, researchers switched to the cut pasture two weeks ago. “The grass in this meadow was still very short, so it’s not fun for storks to look for food,” Wickelski explained. In this meadow, he and his colleagues spread the grass they had cut a while ago in the distance. After a while, the first stork flew in and looked for food in the cut grass.

Researchers finally mixed a solution of green leaf scent and sprayed it onto short grassy meadows. After that, the meadows had a strong smell of cut grass and attracted storks from the surrounding area. “This proves that storks have found a way to the feeding grounds through the scent of the air,” says Williams.

This finding contradicts the previous assumption that storks mainly use their eyes to find food. Rather, bird Rely on their sense of smell to do so. “was there Stork I flew more than 25 kilometers from the other side of Lake Constance to the mowed meadows. ” smell It can also play a greater role than previously thought in the foraging activities of other bird species. Birds of prey such as buzzards and red kites are regularly observed flying over freshly cut meadows.

It turns out that the white stork is changing its movement pattern due to changes in the human environment.

For more information:
Martin Wikelski et al, the scent of volatiles in green leaves, attracts white storks to freshly cut meadows. Science report (2021). DOI: 10.1038 / s41598-021-92073-7

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Max Planck Society

Quote: Stork’s thin nose: Birds are drawn to the scent of grass, leafy vegetables (2021, June 21) from Obtained on June 21, 2021 draw.html

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