A Bird's Eye View Trivia Quiz

Answer: pigeons

Pigeons' retina cones contain colorful oil droplets, which act as filters, giving them enhanced color vision. They use a combination of photosensors and light filters that may record as many as five different spectral bands (pentachromacy).

A triple system of color perception (human eyes have three types of cone cells) gives us the ability to detect only three wavelengths.

Answer: reptiles

Reptilian characteristics of birds' eyes are evident in the pecten (a comb-like structure of blood vessels) within the globe of the eye, the ring of bones embedded in the sclera (corneal membrane) and the area surrounding the irises.

Answer: diurnal (active during the day)

Diurnal birds, active during the day, have more cones than rods. Conversely, nocturnal birds such as owls have a higher proportion of rods which gives them more infrared sensitivity.

Answer: True

Like us, birds of prey have eyes located on the front of their heads and are able to judge distances as well as focus on prey at a distance. Having both eyes in the front of the head give birds (and humans) binocular vision meaning the ability to see the same object with both eyes at the same time.

Songbirds, on the other hand, have eyes on the sides of their heads. This gives them very little binocular vision, but rather vision all around. Their sight enables them to watch for predators and is called monocular vision.

Answer: mirror

This is known as the tapetum lucidum and enables light to strike sensory cells in the retina. As a result, birds with a tapetum lucidum see much better at night.

Answer: double cones

The avian retina is believed to possess one of the most sophisticated cone photoreceptor systems. The double cones consist of two adjacent cells known as the principal and accessory members of the pair.

Some birds see more colors than humans and are able to perceive ultraviolet or near-ultraviolet light which humans cannot. Bird retinas, in contrast to human retinas, contain no blood vessels. This prevents shadows and light scattering which decreases human vision.

Answer: to see better

Birds of prey have a disproportionally large number of sensory cells in the upper half of their retinas. This enables them to see better when they look down on the ground rather than looking up above them. To see above them, they turn their heads upside down for a better view!

Answer: lateral

Lens shape varies more among birds than any other vertebrates. Flat eyes are found in diurnal (active during the day) birds with narrow heads such as doves, pigeons and parrots. Globose or more rounded eyes are found in birds with wider heads such as raptors or canaries and finches. Tubular eyes are characteristic of nocturnal birds of prey, such as owls.

Lateral would apply to the position of the eyes rather than the shape.

Answer: magnification

This is called a nictitating membrane. Unlike the upper and lower eyelids, the nictitating membrane moves horizontally--something like a windshield wiper! It sweeps excess fluid into the corner of the eye where it drains. In most birds, the nictitating membrane is transparent, so vision is not impaired when the eyelid blinks.

Answer: cleansing

Birds of flight operate in the environment of the sky, and rely on their comprehensive visual perception in three-dimensional space for navigation. Birds that live on seeds, fruits or flowers need to differentiate between green and the colors of their food. Ultraviolet vision enables aquatic birds to focus underwater. Also ultraviolet vision is useful for a hunting bird in spotting the traces left by prey.

For example, the urine and feces of mice are visible in the ultraviolet range and stand out against the uniform color of a field.