Nature Watch
The Nature of Seeing
By Susan Thurn,
Cable Natural History Museum
For four years now I have written this Nature Watch column every week. I have written about what to watch for in nature. I have received thousands of comments and heard stories from readers about their own observations in our north woods natural world. We are all phenologists, those who study the seasonal changes in nature, and we primarily do this through sight. We notice a movement out of the corner of our eye and suddenly see our first pileated woodpecker. A flash across the road comes in front of us and we have just spotted a timber wolf. It is our sight, an amazing sense, which provides such an important skill for discovering what surrounds us.
Our eyes contain many essential parts, but two of the most interesting to me include rods and cones. Inside our retina, a part of our eye the size of our thumbnail, are about 150 million light-sensitive rods and cones. Rods help us identify shapes using light. Cones identify color. Both cells then send information to the brain (believe it or not, the image sent to the brain is upside down, and then our brain turns the image right side up and interprets what we are looking at.) These are amazing details and operations that occur, but let us take a look at some specific animals and their visual adaptations.
An owl, if it could read, could read a newspaper from the other end of a football field. This makes sense since their eyes are one-third the size of their heads. They can see a mouse moving over 150 feet away with light equal to that of a candle. They can follow their prey with a head that can turn 270 degrees in each direction. Their relative, golden eagles, can see a rabbit from two miles away. This is astonishing eyesight!
Other daytime birds can see greater ranges of colors, including ultraviolet light. Pigeons have more cones than humans, so can see millions of different hues and are thought to be perhaps the best on our planet at detecting color.
Most snakes have two ways of seeing. Their eyes detect color quite well, but they also have a deep pocket called a pit organ that detects their prey in infrared. Chameleon's eyes can look in different directions at the same time. Frogs must pull their eyeballs in their body to blink. In the fish world, a flounder has both eyes on the same side of their body, allowing them to lie flat on the floor with both eyes looking upward.
Insects are famous for their compound eyes with many tiny parts. Some insects have up to 30,000 lenses in each eye in a honeycomb pattern. Each lens then makes up a small part of the overall picture like a jigsaw puzzle. This vision helps them in detecting movement, which comes clear to us as we try to swat a fly or mosquito! A dragonfly’s brain works so quickly that most movement they see appears to them in slow motion.
Some insects see color, although not as clearly. Butterflies can see colors better than humans while others cannot see as many. Bees see blue, green, and ultraviolet colors but do not see red.
Crab and shrimp are animals with some of the least developed vision. They have compound vision like insects, but with far less detail. Instead, they are very skilled at detecting movements, a behavior that helps them avoid predators.
Perhaps the next time we see the night-time flash of a nocturnal animal’s eyes, we’ll better appreciate how animals see the world. It amazes me that such amazing visual abilities exist in animals, and this is an exploration of only one of their senses!
The place in which we live brings continual wonder. It is this variety that adds to our days, and has added to the many articles in which I have enjoyed sharing throughout the past few years. This issue will be the last Nature Watch written by my hand. It has been great fun writing and learning with you, and I have loved every minute of it! Readers will now be able to enjoy the energy of new Museum staff who will share the wonders of the natural world. However, if you see me on out on the trail, or on the street, I hope you’ll continue to share the stories of your own adventures in our incredible north woods.
For over 44 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 in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opens in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on the web at www.cablemuseum.org, on Facebook, or at our blogspot, http://cablemuseumnaturewatch.blogspot.com/ to learn more about our exhibits and programs.
Wednesday, June 29, 2011
Thursday, June 16, 2011
Tick,Tick,Tick
Nature Watch
By Susan Thurn,
Cable Natural History Museum
I went walking through a grassy field today and afterward felt like I was covered in ticks. Every single one of them was a wood tick, which I would prefer to a deer tick any day. A few moments later, the ticks were nothing compared to the mosquitoes. Still, wood ticks are a part of our northwoods life. We walk through our yards and find them on our pants afterward. We dedicate moments at events to tick races. We have wood tick festivals that include music, cook-offs and other events dedicated to fun in the northwoods in spite of the ticks.
Many people think that ticks are insects, but with their eight legs they actually belong to the spider/arachnid family. All ticks begin life as an egg, and after hatching, the larva is called a seed tick, and it feeds on a small mouse or bird. The larval tick then develops into a larger nymph. This tick then feeds on a host and molts into an even larger adult. Finally, male and female adults feed on a host such as raccoons, dogs, or other large mammals, and the males often look for the female while on the host. Then the females lay up to 5,000 eggs after their last feeding.
When latching on to their host with their two-part mouth, they use saliva to create a cement-like connection. They use their mouthpart to cut a hole in the epidermis, or top layer of skin. Ticks excrete an anticoagulant to keep the blood from clotting. They have adapted quite well to feed on their hosts!
For the many who believe that ticks jump from trees, this is actually a myth. Ticks actually wait for their host animals from the tips of taller grasses and shrubs. With eight legs, they use the back two legs to hold on to a piece of grass. The front six legs are then used as seekers to continue sensing their next “dinner.” Ticks sense heat and carbon dioxide from their host, so when brushed by a moving animal or person, they quickly let go of the vegetation and climb onto the host. Ticks can only crawl, not fly or jump. Any ticks that have been found on our scalps crawled there from our lower body parts. Some species of ticks will crawl several feet toward a host. A study in northern California states that if a human sits on a log for five minutes, they have a 30% chance of having a tick crawl on to their body. Although most spiders and insects are not active until the temperatures reach about 60 degrees Fahrenheit, ticks can be active at a much cooler 45 degrees.
The best method to remove a tick is to try to use tweezers to flip the tick’s body so that it is almost upside down, and then pull straight up to try and remove the tick. Doctors recommend great caution in trying NOT to squeeze the tick, as any diseases that may exist in the tick can actually be squeezed back into our bodies. The best prevention is to regularly check our bodies for ticks, and when outdoors, put our socks up over our pant legs, and wear lighter-colored clothing (it is believed that darker colors more closely resemble that of darker-furred animals so common in our northwoods environment.)
For over 43 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 in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opens in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on the web at www.cablemuseum.org, on Facebook, or at our blogspot, http://cablemuseumnaturewatch.blogspot.com/ to learn more about our exhibits and programs.
By Susan Thurn,
Cable Natural History Museum
I went walking through a grassy field today and afterward felt like I was covered in ticks. Every single one of them was a wood tick, which I would prefer to a deer tick any day. A few moments later, the ticks were nothing compared to the mosquitoes. Still, wood ticks are a part of our northwoods life. We walk through our yards and find them on our pants afterward. We dedicate moments at events to tick races. We have wood tick festivals that include music, cook-offs and other events dedicated to fun in the northwoods in spite of the ticks.
Many people think that ticks are insects, but with their eight legs they actually belong to the spider/arachnid family. All ticks begin life as an egg, and after hatching, the larva is called a seed tick, and it feeds on a small mouse or bird. The larval tick then develops into a larger nymph. This tick then feeds on a host and molts into an even larger adult. Finally, male and female adults feed on a host such as raccoons, dogs, or other large mammals, and the males often look for the female while on the host. Then the females lay up to 5,000 eggs after their last feeding.
When latching on to their host with their two-part mouth, they use saliva to create a cement-like connection. They use their mouthpart to cut a hole in the epidermis, or top layer of skin. Ticks excrete an anticoagulant to keep the blood from clotting. They have adapted quite well to feed on their hosts!
For the many who believe that ticks jump from trees, this is actually a myth. Ticks actually wait for their host animals from the tips of taller grasses and shrubs. With eight legs, they use the back two legs to hold on to a piece of grass. The front six legs are then used as seekers to continue sensing their next “dinner.” Ticks sense heat and carbon dioxide from their host, so when brushed by a moving animal or person, they quickly let go of the vegetation and climb onto the host. Ticks can only crawl, not fly or jump. Any ticks that have been found on our scalps crawled there from our lower body parts. Some species of ticks will crawl several feet toward a host. A study in northern California states that if a human sits on a log for five minutes, they have a 30% chance of having a tick crawl on to their body. Although most spiders and insects are not active until the temperatures reach about 60 degrees Fahrenheit, ticks can be active at a much cooler 45 degrees.
The best method to remove a tick is to try to use tweezers to flip the tick’s body so that it is almost upside down, and then pull straight up to try and remove the tick. Doctors recommend great caution in trying NOT to squeeze the tick, as any diseases that may exist in the tick can actually be squeezed back into our bodies. The best prevention is to regularly check our bodies for ticks, and when outdoors, put our socks up over our pant legs, and wear lighter-colored clothing (it is believed that darker colors more closely resemble that of darker-furred animals so common in our northwoods environment.)
For over 43 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 in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opens in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on the web at www.cablemuseum.org, on Facebook, or at our blogspot, http://cablemuseumnaturewatch.blogspot.com/ to learn more about our exhibits and programs.
Thursday, June 9, 2011
Fledglings
By Susan Thurn,
Cable Natural History Museum
It is not an action we see in the natural world very often. It happens in tremendous numbers every spring, yet we humans rarely get a glimpse at it. Sometimes it is a simple plop, plop, plop, as the fledgling wood ducks drop from their wood cavity or wood duck house into the water or a swoop as a bird leaves its nest. The process of birds leaving their nest is so common, yet not often seen. Why is that?
Many bird nests are very difficult to find, hidden nicely among the camouflaged plants. Young fledglings are also expert ventriloquists, something that helps them evade predators. Their sounds are usually short notes that become faster whenever an adult brings food.
A baby bird is sometimes called a fledgling, the stage in which the young bird’s life has wing muscles and feathers that are developed enough for flight. It is also considered the time when parents of a chick raise it to a fully grown state. Sometimes the birds have begun flying, but are still dependent upon care and feeding from their parents. Other times birds are “fledged” once they leave the nest, even if they still haven’t flown.
Contrary to what we might think, songbirds don't "learn" to fly, and their parents don't "teach" them. Young birds have innate abilities to fly as their bodies mature gradually. When they are physically ready for flight they will fly.
It is common during June for humans to see immature birds sitting on the ground or hopping around without sign of their parents. This is a normal occurrence, as the parents are probably either hiding, watching quietly nearby or are not far away collecting food.
How can we know when we see fledglings? They are usually clumsier and less active than adults, and may have lingering tufts of down feathers and a shorter tail. They will sometimes sit in place, fluttering their wings and gaping their beaks when adults bring food. Most songbirds have a brightly-colored inner beak to help parents find their mouths, but this feature is lost as they age. As they mature, many fledglings will follow their parents, begging constantly for food.
Young of open-nesting songbirds often leave their nests within fourteen days. However, the cavity-nesting tree swallow stays in its nest longer, up to 19 days if the weather conditions and food availability are good. More young in the nest also can take longer for them to mature. With tree swallows, only 85% of their feathers are fully grown when they fledge and attempt to fly.
Pigeons stay in their nests until they are almost adults. The nests are also well-hidden, so are difficult to find, as is true of so many birds. Pigeons sometimes become even bigger than their parents as they feed and get ready to be out of the nest on their own.
Robin nestlings are fed at first by regurgitated food, then larvae or whole earthworms. After they fledge and leave the nest, the young are fed by the male for at least two more weeks. This assistance from the male allows the female to begin another clutch of eggs.
There are many more interesting stories about birds and their parental care of young. Birders are beginning to gain more interest in observing the fledgling process, recording the young birds’ calls and learning identification techniques. If you have your own stories to share about observations of birds fledging in your own back yard, be sure to share it at the Nature Watch blogspot address listed below.
For over 44 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 in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opens in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on the web at www.cablemuseum.org, on Facebook, or at our blogspot, http://cablemuseumnaturewatch.blogspot.com/ to learn more about our exhibits and programs.
Cable Natural History Museum
It is not an action we see in the natural world very often. It happens in tremendous numbers every spring, yet we humans rarely get a glimpse at it. Sometimes it is a simple plop, plop, plop, as the fledgling wood ducks drop from their wood cavity or wood duck house into the water or a swoop as a bird leaves its nest. The process of birds leaving their nest is so common, yet not often seen. Why is that?
Many bird nests are very difficult to find, hidden nicely among the camouflaged plants. Young fledglings are also expert ventriloquists, something that helps them evade predators. Their sounds are usually short notes that become faster whenever an adult brings food.
A baby bird is sometimes called a fledgling, the stage in which the young bird’s life has wing muscles and feathers that are developed enough for flight. It is also considered the time when parents of a chick raise it to a fully grown state. Sometimes the birds have begun flying, but are still dependent upon care and feeding from their parents. Other times birds are “fledged” once they leave the nest, even if they still haven’t flown.
Contrary to what we might think, songbirds don't "learn" to fly, and their parents don't "teach" them. Young birds have innate abilities to fly as their bodies mature gradually. When they are physically ready for flight they will fly.
It is common during June for humans to see immature birds sitting on the ground or hopping around without sign of their parents. This is a normal occurrence, as the parents are probably either hiding, watching quietly nearby or are not far away collecting food.
How can we know when we see fledglings? They are usually clumsier and less active than adults, and may have lingering tufts of down feathers and a shorter tail. They will sometimes sit in place, fluttering their wings and gaping their beaks when adults bring food. Most songbirds have a brightly-colored inner beak to help parents find their mouths, but this feature is lost as they age. As they mature, many fledglings will follow their parents, begging constantly for food.
Young of open-nesting songbirds often leave their nests within fourteen days. However, the cavity-nesting tree swallow stays in its nest longer, up to 19 days if the weather conditions and food availability are good. More young in the nest also can take longer for them to mature. With tree swallows, only 85% of their feathers are fully grown when they fledge and attempt to fly.
Pigeons stay in their nests until they are almost adults. The nests are also well-hidden, so are difficult to find, as is true of so many birds. Pigeons sometimes become even bigger than their parents as they feed and get ready to be out of the nest on their own.
Robin nestlings are fed at first by regurgitated food, then larvae or whole earthworms. After they fledge and leave the nest, the young are fed by the male for at least two more weeks. This assistance from the male allows the female to begin another clutch of eggs.
There are many more interesting stories about birds and their parental care of young. Birders are beginning to gain more interest in observing the fledgling process, recording the young birds’ calls and learning identification techniques. If you have your own stories to share about observations of birds fledging in your own back yard, be sure to share it at the Nature Watch blogspot address listed below.
For over 44 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 in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opens in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on the web at www.cablemuseum.org, on Facebook, or at our blogspot, http://cablemuseumnaturewatch.blogspot.com/ to learn more about our exhibits and programs.
Thursday, June 2, 2011
Barren Strawberries
Nature Watch
By Susan Thurn,
Cable Natural History Museum
When we walk through the forest right now we see the beautiful white of the trilliums, the white of the spring beauties, hepatica, bloodroot, starflowers, spring anemones, the multi-colors of the wild violets, and one of my favorites, the yellow barren strawberries.
Barren strawberries are common in woods and clearings, rising up out of the ground from 3-8 inches. The yellow flowers have five petals that bloom into June. A flower that belongs to the rose family, its leaves are made up of three leaflets on long stalks that are oval-shaped, with broad teeth. The fruits are not really berries, but have single seeds that are inedible, which is where the name barren strawberry comes from. It also grows close to wild strawberries.
Easily grown in well-drained soil in full sun to part shade, barren strawberry spreads across the ground with runners, or rhizomes that creep just below the surface of the soil. They can grow in many soil types, but actually prefer slightly acidic soils. Due to its adaptability, this plant can be found in a variety of habitats such as meadows, deciduous or mixed-hardwood forests. Plants often seen growing along with barren strawberries include sugar maple, white ash, ostrich or cinnamon fern, and false solomon’s seal.
Barren strawberries are considered an endangered species or plant of special concern in some states. Garlic mustard and other invasive plant species have pushed out this plant in many habitats. In other areas barren strawberries are used as native plant ground cover for difficult areas around our homes. It has even been used in xeriscape gardens because it is drought tolerant.
Spring brings so many amazing things to observe every day. Be sure to get outdoors in our northwoods back yards to enjoy it all!
For over 44 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 in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opens in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on the web at www.cablemuseum.org, on Facebook, or at our blogspot, http://cablemuseumnaturewatch.blogspot.com/ to learn more about our exhibits and programs.
By Susan Thurn,
Cable Natural History Museum
When we walk through the forest right now we see the beautiful white of the trilliums, the white of the spring beauties, hepatica, bloodroot, starflowers, spring anemones, the multi-colors of the wild violets, and one of my favorites, the yellow barren strawberries.
Barren strawberries are common in woods and clearings, rising up out of the ground from 3-8 inches. The yellow flowers have five petals that bloom into June. A flower that belongs to the rose family, its leaves are made up of three leaflets on long stalks that are oval-shaped, with broad teeth. The fruits are not really berries, but have single seeds that are inedible, which is where the name barren strawberry comes from. It also grows close to wild strawberries.
Easily grown in well-drained soil in full sun to part shade, barren strawberry spreads across the ground with runners, or rhizomes that creep just below the surface of the soil. They can grow in many soil types, but actually prefer slightly acidic soils. Due to its adaptability, this plant can be found in a variety of habitats such as meadows, deciduous or mixed-hardwood forests. Plants often seen growing along with barren strawberries include sugar maple, white ash, ostrich or cinnamon fern, and false solomon’s seal.
Barren strawberries are considered an endangered species or plant of special concern in some states. Garlic mustard and other invasive plant species have pushed out this plant in many habitats. In other areas barren strawberries are used as native plant ground cover for difficult areas around our homes. It has even been used in xeriscape gardens because it is drought tolerant.
Spring brings so many amazing things to observe every day. Be sure to get outdoors in our northwoods back yards to enjoy it all!
For over 44 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 in Cable at 13470 County Highway M. The new exhibit, The Joy of Birds: Feathers in Focus opens in May, 2011. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Also discover us on the web at www.cablemuseum.org, on Facebook, or at our blogspot, http://cablemuseumnaturewatch.blogspot.com/ to learn more about our exhibits and programs.
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