As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Tuesday, 5 April 2016

What Does A Bird See?

Commentary by Mari Carbajal

There’s an abundance of bird species, most of which have specialized traits that help them get through their day.

Not all species of birds have large talons to catch their prey, or are able to drill a hole to hide their food. But no matter what species you choose to examine, all birds share one unique visual capability – the ability to see the standard color range, but also the reflective ultraviolet light spectrum.

This unique sense is crucial for finding food, locating a mate, spotting prey, and a whole lot more.

Cones in the retina of the eye are cells responsible for detecting color. Humans only have three cones (red, blue and green), but birds can have four cones or more, depending on the species. This allows them to see within the spectrum of ultraviolet light.

Birds that are active during the day have better detection of color than birds active at night. Nocturnal birds such as owls have a larger number of cells that allow them to enhance their sight in low-light conditions. They might not see colors as clearly as diurnal birds, but having more rod cells lets in more light.

Having such an exceptional sense certainly changes a bird’s perspective on everything in its environment. Birds can see visible colors more distinctly than a human because each cone in a bird’s eye holds a drop of colored oil that selectively filters out specific colors. This is similar to how a camera lens works. It gives the bird greater sensitivity to shades of colors. In turn, it allows the bird to visualize contrast in its surroundings. It then gives them the ability to see through other prey’s camouflage.

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