Get some distance and see which one is easier to spot. Place a white and dark tissue out in a full-moon night. If you don’t, make this experiment yourself. Now, you may think that moonlit nights will be even worse for white owls.

As a consequence of this, dark-red owls bring less rodents to their owlets during these moonlit nights, and the owlets have less chances to survive. Moonlight makes easier for the rodents to spot the owls flying around them, the same it makes fieldwork easier for us when our headlamps run out of batteries. And again, the reason for this is the Moon.Īs the nights become more illuminated by the moon, dark-red owls have a worst time in hunting the little rodents with which they feed their owlets. We don’t fully understand yet why such different colours evolved but we are now sure that by night, not all the barn owls have the same colour. Some are snowy white, because they lack pigments in their feathers, like we humans lack them on our hair as we grow older. Some are dark reddish, because they have on their feathers the same pigment (pheomelanin) as red-hair humans have. Like cats, like humans, like many animal species, barn owls come in different shades of colour. Those are the nights when a full Moon is up in the sky, fabricating shadows and escorting barn owls and us in our nightly routine. When the Sun is far below the horizon and yet its light is all around. Those are the nights when head lamps are barely useful. Only some nights, it is fine to go on the field unequipped. You don’t want to be out there, going five or more metres up a ladder to check a barn owl nest box in the pitch dark. When you do field work by night, the first thing you learn is to make sure you have packed your head lamp and some batteries … and an extra head lamp and some more batteries for the forgetful newbies. People in the area say “la nuit, tous les chat sont gris” (all cats are grey by night). Unfortunately for us, a group of biologists of the University of Lausanne, we are banned from such a view as we travel around the valley once the sun is down, the night takes over, and barn owls are out to hunt. The rocky and snowy Alps and Jura mountains enclose a valley where neatly worked agricultural fields, old farms, tobacco barns, and a castle here and there offer one of the most picturesque scenes of the Helvetian country. The mountainous landscape of Switzerland takes a break between the Neuchâtel and Geneva lakes.

Owl and moon story