In this week’s Under the covers (Nature revealed) blog, Nature’s Art Director Kelly Krause discusses the inspiration behind this week’s front cover choice.
Many migrating birds rely on the Earth’s magnetic field for their sense of direction, although what mechanism they use to detect this extraordinarily weak field is unknown. Following the surprise observation that night-migratory songbirds (European robins) tested between autumn 2004 and autumn 2006 in wooden huts on the University of Oldenburg campus seemed unable to orient in the appropriate migratory direction, Henrik Mouritsen and colleagues performed controlled experiments to establish what was happening. They find that robins lose the ability to use the Earth’s magnetic field when exposed to low-level AM electromagnetic noise between around 20 kHz and 20 MHz, the kind of noise routinely generated by consumer electrical and electronic equipment.
Interestingly, the magnetic component of this electromagnetic noise is a thousand times weaker than the lower exposure limits adopted in current World Health Organization (WHO) guidelines, yet it can disrupt the function of an entire sensory system in a higher vertebrate. The birds regain the ability to orient to the Earth’s magnetic field when they are shielded from electromagnetic noise in the frequency range from 2 kHz to 5 MHz or when tested in a rural setting. Credit: Kim Taylor–Dorling Kindersley–Getty/ Karl Harrison–Henrik Mouritsen
From the Art Desk:
Art Director, Kelly Krause, explains:
“As explained in the caption, migratory robins lose their ability to use the Earth’s magnetic field as a compass when exposed to the sort of noise generated by consumer electronic equipment. An image of the species from the paper (the European robin) seemed like the most logical thing to show on the cover. As we have featured various birds on our covers over the years, illustrating a variety of research topics (say, habitat loss or a genome sequence), it was important to me to give a sense of ‘migration’ and ‘noise’ to this particular cover, to give a clear impression of their research topic at a glance.
“Early on, the authors submitted a beautiful photo of a robin perched on a post, in the soft lighting of late afternoon. Migratory robins determine their migratory path for their night-time flights in the early evening, around sunset. It was a beautiful image, and scientifically relevant, but it felt a bit too static for the cover. So in the end we sourced an image of a European robin in flight from a specialist wildlife photographer.
“The authors were kind enough to provide us with photos of the correct sort of radio masts that causes the problem for the birds, as well as an image of electromagnetic waves.
“In the end, I combined several elements to create an abstract representation of the research, showing the mast, waves, and a European robin in flight, to give a sense of ‘migration’ and movement, along with noise. I put it all on a white, almost ghosted, background, to make sure that the setting was not realistic, as of course this species would never migrate during the day.”
Watch the news video Lost in Migration