Imagine living on the African plains, spending most of your day finding food to fill your daily calorie load. In addition, there are predators in the shadows, not far away; you have to always watch your back. Sounds like stressful life, doesn’t it?
In a way, we all know being stressed is bad for the health. Nevertheless, stress response is an evolutionary trait with benefits—exhibited by numerous members of the animal kingdom. Becoming stressed generates a series of physiological changes that prepare animals for the Fight-or-Flight behaviour. The level of stress hormone, corticosteroids rises and activates the body: the heart start racing, breathing is faster, and the muscles become tensed. So, for the 30 seconds that you find a lion chasing after you, stress is very helpful and essential to your survival. Continue reading
Personally known for wrecking havoc on my neighbour’s garbage and upturning my lawn at home for grub, the ever present crows are typically regarded as pests. The documentary, A Murder of Crows, which presents the research of several scientists, including Dr. John Marzluff, aimed to change the way people view crows. CBC offers the documentary here.
Photo by: Lucina M via Flickr
At first glance the title, A Murder of Crows, sounds ominous, but a ‘murder’ simply refers to a group of crows. In fact, social and generational learning amongst a crow community are highlighted during the film.
Dr. Marzluff and his research team at the University of Washington conducted an experiment to see if crows could recognize a certain face and associate it with danger. Researchers wore a human mask, dubbed the ‘danger’ mask, then caught and released several crows on campus. Later, when researchers clad in the danger mask walked near the previously captured crows, the crows recognized the mask face then responded by circling overhead and voicing stressed warning caws. Researchers clad in other masks did not disturb the crows. Amazingly, this response to the danger mask was replicated by the entire crow community on campus, which included the children of the released crows that learnt through observing their parents. Even two years later, the danger mask still elicited a response from the crows!
Another astonishing aspect of A Murder of Crows is the segment about crow intelligence. Crows in urban Japan were able to compensate for the limited availability of nest building branches by utilizing coat hangers as nest components. New Caledonian crows were shown to be capable of sequential tool use that required using a tool to obtain another tool to get food. This intelligence, which sometimes required thinking three steps ahead, is matched by few species on Earth.
Sequential tool use demonstrated by ‘Betty’ the New Caledonian:
Prior to watching A Murder of Crows, I knew crows were intelligent, but not to this magnitude. I have come to appreciate crow intelligence and their ability to thrive in urban environments. The narrator also candidly remarked that the US Department of Defense was interested in the research. In the future, we may even see crows used for identification or tracking purposes!