Monday, February 22, 2010

Bird Tongues

By Susan Benson,
CNHM Director of Education

I love my tongue. I love it as I sing with it, taste with it, talk with it, whistle with it, or hoot with it. Just the thought of dark chocolate melting on my tongue makes me smile. Oh the joy my tongue can give me! Our human tongues are important for these reasons, but for most birds, their tongue is used for a reason that doesn’t have much to do with communication. Their tongues are used more for grasping or manipulating food. Check out these bird tongues and their functions:

• Most sadly, birds do not have tongues for tasting. Birds have the misfortune of having almost no taste buds. Chickens only have twenty-four taste buds, and parrots’ taste buds number in the hundreds.
• Most birds have a simple tongue with a flat, triangular blade with “papillae” at the back of the mouth that point backward, ensuring that their food goes in one direction. Penguins have a tongue covered with backward pointing spikes to help swallow fish.
• In cormorants, pelicans, or kingfishers, which scoop and swallow their food whole, the tongue is very small.
• Brush-tongued lories have a tongue with a small brush at the tip that they use to collect flower nectar. Hummingbirds have long, hollow tubes forked at the end into two curled channels that allow them to dip into a flower, three to twelve times a second, to lap up flower nectar. It is believed that capillary action causes the liquid to be pulled up into the troughs. When the bird retracts its tongue, pressure on the tongue squeezes the liquid out.
• For many birds, their tongues are supported by five tongue bones, bones and cartilage called the “hyoid apparatus.” Their tongue is harder and less flexible than human tongues.
• A woodpecker has a barbed tongue, with a spear-like tongue bone that can extend up to four times the length of its beak to grasp insects from a tree. Their tongue, as part of the hyoid apparatus, wraps around the skull and anchors at the base of the bill. Some have a sharp pointed top to spear wood-boring insect larvae. Others have a tongue tip that has backward pointed barbs to help extract insects from the holes, and the tongue is coated with sticky saliva to help stick to the prey. Sapsucker tongues have hair-like extensions on their tongue tips to capture sap through capillary action. In some woodpecker species, part of the hyoid process has joints between the bones of the skull and upper jaw with muscles to absorb the shock of hammering.
• Birds that feed on seeds or fruits, such as parrots, are likely to have well-padded, thicker tongues that also enable them to make sounds that we enjoy so much we often desire them as pets.
• A ducks upper bill is specialized for filtering out food from the water. They get a mouthful of water and the tongue moves the water out. A flamingo has spiny barbs on the sides of its tongue to filter out microorganisms.

“Sally sells seashells by the seashore” is a tongue twister that we all may know well, but knowledge of birds’ tongues brings an entire meaning to the concept. Be sure to watch birds around your home or feeders in a new way – you just might see their tongues at work!

For over 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, Our Shared Planet, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.

Monday, February 15, 2010

Bird Eyesite

By Susan Benson,
CNHM Director of Education

Did you know that if an owl could read, it could read a newspaper from the other end of a football field? Or that a golden eagle can see a rabbit from two miles away? Or that our eyes would need to be the size of grapefruit in order to have the same visual ability of birds of prey? Birds truly have amazing visual abilities!

Birds’ eyes sometimes weigh more than their brains. They can see with similar clarity to that of humans, but they can process the information they see much better than humans. All birds can see with binocular and monocular vision. This means that their eyes can work together to see straight ahead, and can also see out of each eye independently.

Monocular vision is the reason that birds have their eyes located in different places on their head. The pigeon has eyes on the side of its head, which enables them to see in all directions except right behind themselves. An American robin cocks its head to one side, appearing to be listening. In reality, it is turning its head to use its monocular vision to spot an earthworm on the ground. The American woodcock's eyes are closer to the top of their head to enable them to see behind.
For bald eagles, this combination of binocular and monocular vision means they can see fish in the water from several hundred feet above, quite an accomplishment since fish are counter-shaded with darker colors on top to make seeing from above harder. Additionally, eagles and other birds of prey have more visual cells – hawks have one million cells compared to humans which have about two-hundred thousand cells. Eagles also have color vision. Combine these skills, and an eagle can fly 1000 feet above an open area and spot prey for an almost three square miles.

The ability to see color is a big advantage to birds. Birds have an area in their retina which contains colored droplets of oil. Kingfishers have more oil than other birds, and scientists believe this helps block the glare from the water. Pigeons have brighter drops of yellow oil, which might help dull the brightness in the sky.
Birds, like humans, also have rods and cones. Rods let in available light, and cones detect color. Nocturnal birds like owls have more rods, which help them detect prey in low light levels. They also have fewer cones, which help discriminate shapes and colors, making it difficult for owls or other nocturnal birds to see finer details. Birds more active during the day have more cones, since the presence of light is needed to see color. In addition to this, birds can also see ultraviolet light—part of the light spectrum that humans can’t see. Many birds show different ultraviolet patterns that are not visible to humans, but are believed to assist birds with courtship. Birds whose male and females look the same to us look different from an ultraviolet perspective. This ultraviolet receptor might also help birds with foraging for food, as some waxy berries and fruits reflect ultraviolet light to perhaps advertise their location.

A “bird's eye view” or “an eagle eye” are words that take on new meaning when we realize how complicated bird vision really is. It also makes it more understandable why “sneaking” up on birds to view them closer can be so difficult. That elusive warbler will always continue to be hard to find when our slightest movement is so easily detectable. However, please do not let that dissuade anyone from doing what we can to keep on observing these beautiful creatures!

For over 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, Our Shared Planet, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.

Tuesday, February 9, 2010

Pileated Woodpeckers

By Susan Benson,
CNHM Director of Education

Thunk! Thunk! Thunk! This was the sound I heard outside my house while building a snowman in the recent wet, heavy snowfall. I looked over and with great excitement, spotted a pileated woodpecker. I watched while it pounded against the base of a tree, snow flying as the bird scooped it behind itself. These large woodpeckers are almost crow-sized, with a wing spread of up to 30 inches. This bird, a model for the cartoon character Woody Woodpecker, is mostly black with a large red crest on its head. White stripes run down the face to the neck. Their wild laughter-like call and drumming can be heard long distances through a forest. There are a lot more interesting facts about pileated woodpeckers!

What is their habitat? Pileated woodpeckers prefer mature forests, but have adapted to second-growth forests. In younger, select-cut forests they use large trees left behind.

What do they eat? When pileated woodpeckers hear an insect under the bark, they begin pecking with their beaks. They have a thick skull to avoid headaches. Their tongue is long with a sharp end for spiking insects inside the tree, and also has a sticky section to attach to the insects. This woodpecker prefers carpenter ants and wood-boring beetle larvae. Their straight bill is also good for collecting fruits and nuts. They seem to be great carpenters, boring large holes into tree trunks. They can pry off long slivers of wood to expose their food, and make elongated holes so they can “dig” deeper into the tree and still accommodate their body size. These excavations are so extensive that they can attract other woodpeckers and even wrens to the same feeding sites.

How else do they use their carpentry skills? Pileated woodpeckers raise their young in tree holes, using a new hole each year in a dead tree or branch. It can take up to six weeks to pound out their new nesting site. A roosting site often has multiple entrances. Sometimes their cavities can cause a smaller tree to break in half! Once the holes are abandoned, they provide homes for other forest songbirds.
What are other interesting pileated woodpecker facts? If an egg falls off the nest, they have been observed moving their eggs, a rare habit in the bird world. A sad fact is that because they often choose taller, mature trees, they face danger from lightning strikes.

Pileated woodpeckers are unforgettable. Once you see one, you will never forget what it looks like, and once you learn to recognize their laughing call, you can laugh in response just hearing it. It is also worth trying to catch a glimpse of it in flight with its black body and white wing linings, mixed with its swooping flight. And how is it pronounced – with the long or short i? According to the resources I searched, either way works!

For over 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, Our Shared Planet, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.

Tuesday, February 2, 2010

Saw-Whet Owl

By Susan Benson,
CNHM Director of Education

He came out on his porch, and right on the railing was an owl – a saw-whet owl. The owl was startled, and flew to a nearby tree, where a he watched it for a while at his house. I listened to this story at the Museum, wishing I could have seen this myself as the saw-whet is a bird that continues to be on my must-see life list. I have not yet had the fortune to observe one, but think they are spectacular birds.
How do we identify a saw-whet owl? These owls are only seven to eight inches tall, have a white face outlined in brown and white, with yellow eyes but no ear tufts. Their underparts are white and streaked with brown. They have an asymmetrical skull that makes their head sometimes appear distorted.

Behavior or location can also help with identification of this bird. We can best find the northern saw-whet owl in deciduous and coniferous forests that have thicker understory or shrubs. Other preferred habitat includes areas with older deciduous trees that have existing woodpecker cavities, and forests near wetland habitat. During the day saw-whets roost in tree cover close to the ground. Saw-whet owls tend to shuffle their feet when sitting, and look larger when in flight because of their broad wings. When threatened, they stretch their body out to look like a branch, sometimes bringing a wing around to the front of their bodies. They also tend to stay in one place rather than flying away when scared, causing people to think they are tame. We can recognize their call, which occurs mostly between March and May and sounds like a repeated, whistle-like “hoop” that can last for hours without a break. Their name comes from their alarm call that sounds like the whetting of a saw.

Saw-whet owls hunt at dusk and dawn, waiting until they spy prey, then swooping down to catch them from low hunting perches and heavy shrub cover. They feed mostly on small mammals that include deer mice, shrews, voles, squirrels, bats, flying squirrels, and house mice. Frogs, insects, and birds up to cardinal size can be killed by saw-whets. Sometimes these small owls will eat a mouse in two meals. When prey is plentiful, they will often eat only the head of their prey. In winter they will also kill several mice quite quickly and cache them in hiding places, saving them for a later date when they can thaw out and eat the carcass. What a clever use of nature’s freezer!

Night-time is truly a great time to enjoy the outdoors, even in winter. So many nocturnal animals can bring us the same exciting discoveries that diurnal animals can. Sometimes we do not have to go far, as the next observation might be right outside our doorway!

For over 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, Our Shared Planet, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.