By Laetitia Desbordes
Imagine a cold night in the boreal forest, where the sky is set ablaze with hypnotic auroras: a breathtaking spectacle. The year 2024 has been marked by numerous displays of these lights, capturing the attention of scientists and dreamers alike. But beyond this visual beauty, these celestial phenomena raise fascinating questions about their impact on the wildlife living under these sparkling skies. Could these lights have an effect on our wildlife?
The Solar cycle and its impacts
The solar cycle is a natural phenomenon that lasts about 11 years, during which solar activity fluctuates from periods of low to high activity. Observed by humans for over four centuries, this cycle is marked by variations in the number of sunspots and solar eruptions that release large amounts of particles and energy into space.
Although these events occur at considerable distances from Earth, they have repercussions on the environment, climate, and even technology.
Auroras: a fascinating phenomenon
Auroras are formed when solar particles and powerful magnetic fields from the Sun interact with the atoms and molecules in Earth’s atmosphere. These spectacular light displays occur in regions near the North Pole, called the aurora borealis, and their counterparts in the Southern Hemisphere, known as the aurora australis.
These lights dance across the night sky in various forms, creating a dazzling spectrum of colors. The colors we observe are directly related to the atmospheric particles that interact with the solar particles. Green, for example, which is the most commonly observed color, is associated with oxygen molecules at altitudes below 300 km.
Mammals at the heart of the matter
Mammals, such as the Snowshoe Hare (Lepus americanus) and the North American Porcupine (Erethizon dorsatum), also appear to be influenced by the solar cycle. Canadian studies have shown that their feeding behaviors and abundance may be linked to the variations in sunspot numbers and the resulting climate conditions.
During years of high solar activity, primary productivity increases, which affects food availability.
But what about the winged fauna?
Vagrants incoming!
It is well known that many bird species rely on magnetoreception during migration. However, these internal compasses can be disrupted by powerful solar storms. In North America, studies have shown that migration could decrease by 9 to 17% during such phenomena.
In addition to tropical storms, such as hurricanes, geomagnetic disruptions can also cause disorientation, leading to an increase in the number of lost birds during their migration, forcing them to deviate from their path. This could be what happened to the Western Flycatcher, native to western North America.
The mystery of the Boreal Owls
The Boreal Owl (Aegolius funereus), a small owl living in the boreal forest, is known for its cyclical irruptive movements in North America. These migrations are primarily influenced by the abundance of food, notably the Red-backed Vole (Myodes gapperi), its main prey. Yet, the team at the Tadoussac Bird Observatory recalls that during nights when the auroras dance in the sky, they also record the presence of the Tengmalm’s Owl. Is there a hidden connection between this luminous phenomenon and the presence of these owls?
Boreal Owls can be observed in Tadoussac from mid-September to the end of October during the Northern Saw-whet and Boreal Owl monitoring program.
No Hasty Conclusions
The idea of a correlation between the aurora borealis and the migration of small boreal owls is fascinating, but no scientific evidence has been established, for now. Is it merely a coincidence that these owls cross our sky during light displays, or will the answer remain in the shadows, where science still struggles to fully grasp the impact of solar cycles on our ecosystems?
Fundamental science aim to collect data that, in the long term, may answer unforeseen questions that arise during their launch. So, who knows, maybe one evening, under the aurora-lit sky, an owl will finally reveal the key to this mystery!
