The monthly cycle affects the nightlife in terms of natural light. But, as Luis San-Jose of the University of Lausanne and his team found out, the night light also influences how barn owls are colored or how much they weigh. The scientific team has published its conclusions on long-term observations of burnt owls and several experiments in the science magazine Nature Ecology & Evolution.
Male owls exist in two color variants. At first, the body of owls is all brownish-red, in the second variant, the males have a bright white front body. Theoretically, the brownish-red males should be more successful, because the chances of the prey being spotted are much smaller. Yet the white variant of the burnt owls did not disappear, on the contrary, it flourishes very well.
During the years of monitoring the owl’s nests and watching the owls themselves using GPS, the scientists noticed that during the full moon the brownish-red owl has about 43 percent less loot and their chicks are often hungry. Their already small chance of survival (with owls, the mortality rate fluctuates around 72 percent) continues to decline and their weight is generally lower in adulthood. Female owls, whose partner has brownish-red coloring, even timed the laying of eggs so that their chicks were not as vulnerable as possible during the full moon.
But in the white-colored owls, which are very well visible under the full moon, no decline in success occurred in this period. As San-Jose and his team found out, it may be the effect that we all know of when the game runs into the road, and despite the fact that the car is rushing, it won’t even move.
Dazzling feathers like a perfect paralyzer
Beasts, whose eyes are well suited to vision in the dark, are much more dazzled by bright light. The deer or other animals will then stop and stand until their eyes get accustomed. In the case of their meetings with cars, this is often the last thing the animals can do. As the experiment of the team of scientists showed, the same applies to white-colored owl and their most common prey – the voloquils.
Because observing the voles and the owl in the wild in a sufficient number of experiments is impossible, the scientists used the stuffed owl, which was on the wire over the experimental hraboš. The white glowing feathers of the full moon paralyzed the Rakas for a whole five seconds longer than the brown-red Owl’s feathers.
Why, then, are not all the owl burnt at the front white? Data gathered by scientists showed that under dark conditions, such as high clouds, the white-colored owl is slightly less successful than brownish-red. Scientists further estimate that brownish-red owl is more successful in daily hunting.