Nature Watch
By Susan Benson,
CNHM Director of Education
This week I was driving towards Winter School District to teach science and environmental education for the day, and thought to myself, “What is happening this week in the natural world that I should write about?” Not even thirty seconds later, a black squirrel ran across the road in front of me. I smiled as nature so quickly gave me an answer. What is it that causes these animal colorations?
The official word for this animal coloration is melanism. The black squirrels we see on occasion are really eastern gray squirrels with a genetic mutation. Melanism is an increased amount of black or nearly black pigmentation of skin, feathers or hair. Dark or even black squirrels or deer are said to be melanistic. These animals have too much pigment in their eyes, hair and skin, rather than too little. Biologists estimate that about one of every ten thousand squirrels has black coloration. Melanistic black squirrels can exist wherever gray squirrels live. Gray mating pairs may produce black offspring, and in areas with high concentrations of black squirrels, mixed litters can be found.
This black color phase in squirrels is not believed to be a genetic mistake, however. Before European settlers, it is reported that almost all squirrels in the northern states were black. Black fur absorbs more heat from the sun in our cold northern winters, and the coloration can be a defense in shaded, denser and dark forests. This darker color could have aided in hiding from predators of the sky. One scientist in particular, Dr. Bill Hamilton, suggests that as Europeans settled in this region, forests were cleared, farmland became a common use, and squirrels were hunted extensively as a food source and a perceived threat to farm crops. As this forest became more broken up, the black color was more easily seen, and so began to disappear from the population.
Black squirrels have gained great notoriety throughout the United States. Black squirrels have been introduced into one city to outcompete red squirrels. Some communities had black squirrels gifted to them, while another town has a legend that their populations came from a traveling circus. Some U.S. towns and one in Canada publicize with pride their black squirrel population. At least five colleges use the black squirrel as a symbol or mascot. Local residents in the Chicago area participated in a message board to share their own observations and “scientific” studies on the activities of their local black squirrel populations. Finally, in some alternative weather forecasting, black squirrel sightings are used to predict that devastatingly harsh winters are ahead. Let us hope that my sighting is not evidence that this type of winter is headed our way! In the mean time, enjoy looking for your own black squirrel nearby.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
Monday, November 30, 2009
Thursday, November 12, 2009
White Tail Deer
Nature Watch
By Susan Benson,
CNHM Director of Education
What can reach speeds of up to thirty miles per hour, can leap, and swim, and weigh up to 200 pounds? A white-tailed deer, of course. Mid-November appeals to us all for a variety of different reasons – the last days before winter sets in, the approach of a holiday of thanksgiving, or the approach of the deer hunting season. For me, it continues to be a deer appreciation time as their visibility increases through the next few weeks. White-tailed deer sometimes frustrate me as they chomp off my favorite flowers, but generally they are an animal I really enjoy. After all, how many other places are there where you can see such a large mammal every day of the year?
What interests so many is the obvious movement of deer as the rutting season for white-tailed deer reaches its peak - during the last two weeks of November and into December. Most of us know that bucks often pose themselves, hoping to impress their rivals and avoid physical contact. They may also engage in fights using their antlers and hooves. The fittest bucks, often having the largest racks, gain territory and become the fathers of next year's fawns. They often are the first to drop their antlers shortly after the rut.
Antlers are temporary projections, that although look solid, are honeycombed when observed through a microscope. During the spring, the lengthening of daylight signals more testosterone production, causing antler growth. Neck muscle develops to aid bucks with the additional weight of three to nine pounds. Does can occasionally grow antlers in times when they have a hormonal imbalance. During spring, deer browse heavily to replenish their fat reserves. Does use this energy for milk production, and bucks for antler production. Protein and minerals are necessary, although deer can draw from minerals they have deposited in their skeletons during other parts of the year. The deer also select plants with higher mineral content, and their stomachs can also change absorption rates of minerals.
Antler growth is linked to nutrition. Yearling bucks usually carry spikes, a single bone with no branching pattern, as their bodies focus on muscle and skeletal growth. However, older bucks can carry spikes when faced with poor food conditions. Bucks with higher nutrition can lead to larger antlers, as can genetic factors.
As their antlers grow, their fuzzy velvet supplies blood, and grows a half inch to one inch per day. By August or early September antlers are fully-grown, the bone dies, and the velvet dries and falls off. Contrary to common belief, bucks do not rub their antlers on saplings to remove the velvet, but most likely to strengthen their neck muscles to prepare for upcoming fights. Rubbing also helps relieve their aggression brought on by hormonal changes and communicates to others. Bucks rub their face as well, leaving behind a scent to advertise to other males and females. The duels that follow ensure that natural selection occurs – the strongest males pass along their genes. In addition to using their antlers for sparring, they use them for digging in early snows for food. Following the rut, amounts of testosterone decline and the bucks lose their antlers, usually in January-February, or for deer living in poorer quality habitat, even earlier.
I live among terrific deer habitat, surrounded by forest and agricultural fields, which makes for continual white-tail observations. I am familiar with the “flag” of their tail, perhaps meant as a warning, but to me is a hello and goodbye as they trot away from me across the field. This beautiful animal is just another good reason to live and hang out in the north woods.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
By Susan Benson,
CNHM Director of Education
What can reach speeds of up to thirty miles per hour, can leap, and swim, and weigh up to 200 pounds? A white-tailed deer, of course. Mid-November appeals to us all for a variety of different reasons – the last days before winter sets in, the approach of a holiday of thanksgiving, or the approach of the deer hunting season. For me, it continues to be a deer appreciation time as their visibility increases through the next few weeks. White-tailed deer sometimes frustrate me as they chomp off my favorite flowers, but generally they are an animal I really enjoy. After all, how many other places are there where you can see such a large mammal every day of the year?
What interests so many is the obvious movement of deer as the rutting season for white-tailed deer reaches its peak - during the last two weeks of November and into December. Most of us know that bucks often pose themselves, hoping to impress their rivals and avoid physical contact. They may also engage in fights using their antlers and hooves. The fittest bucks, often having the largest racks, gain territory and become the fathers of next year's fawns. They often are the first to drop their antlers shortly after the rut.
Antlers are temporary projections, that although look solid, are honeycombed when observed through a microscope. During the spring, the lengthening of daylight signals more testosterone production, causing antler growth. Neck muscle develops to aid bucks with the additional weight of three to nine pounds. Does can occasionally grow antlers in times when they have a hormonal imbalance. During spring, deer browse heavily to replenish their fat reserves. Does use this energy for milk production, and bucks for antler production. Protein and minerals are necessary, although deer can draw from minerals they have deposited in their skeletons during other parts of the year. The deer also select plants with higher mineral content, and their stomachs can also change absorption rates of minerals.
Antler growth is linked to nutrition. Yearling bucks usually carry spikes, a single bone with no branching pattern, as their bodies focus on muscle and skeletal growth. However, older bucks can carry spikes when faced with poor food conditions. Bucks with higher nutrition can lead to larger antlers, as can genetic factors.
As their antlers grow, their fuzzy velvet supplies blood, and grows a half inch to one inch per day. By August or early September antlers are fully-grown, the bone dies, and the velvet dries and falls off. Contrary to common belief, bucks do not rub their antlers on saplings to remove the velvet, but most likely to strengthen their neck muscles to prepare for upcoming fights. Rubbing also helps relieve their aggression brought on by hormonal changes and communicates to others. Bucks rub their face as well, leaving behind a scent to advertise to other males and females. The duels that follow ensure that natural selection occurs – the strongest males pass along their genes. In addition to using their antlers for sparring, they use them for digging in early snows for food. Following the rut, amounts of testosterone decline and the bucks lose their antlers, usually in January-February, or for deer living in poorer quality habitat, even earlier.
I live among terrific deer habitat, surrounded by forest and agricultural fields, which makes for continual white-tail observations. I am familiar with the “flag” of their tail, perhaps meant as a warning, but to me is a hello and goodbye as they trot away from me across the field. This beautiful animal is just another good reason to live and hang out in the north woods.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
Thursday, November 5, 2009
Snow Bunting
Nature Watch
By Susan Benson,
CNHM Director of Education
With the amount of snow we have seen in October, it seems only appropriate that the snow buntings have returned for their winter stay. We often see buntings darting away from the roadsides, similar to the juncos, but usually in larger flocks of up to 80 birds. With their white and tan colors, they blur in a flight that reminds us of a swirling snowstorm. These birds are of the Arctic, but we are fortunate to view them during our winters as they travel south.
Imagine flying south to winter in the north woods. While most migrating birds enjoy the southern United States or Central or South America, the snow bunting inhabits most of the northern parts of the United States and Canada. Buntings migrate this short distance to open habitats such as weedy or grassy fields, prairies, low mountains, sandy coastal areas, or sometimes cut-over farmland. Buntings are ground-feeders that feed on grass and other plant seeds from late fall to early spring, and seeds, buds, and insects in their breeding Arctic habitat.
As our winter transitions to spring, just like much of the bird world, the males use their coloration to attract the ladies. However, the snow bunting only has one molt each year, without the alternate plumage that we see on other birds such as the American goldfinch. After the summer molt, the male has the same white underside, brown patches on its face, with a brown and black striped back. Under their colored feather tips, the back feathers are black, and the body feathers are white. To prepare for spring, the male rubs off the brown feather tips in the snow so that he is a showy black and white by April.
These winter bunting visitors will be with us until April, when the males return to their high Arctic breeding grounds. The males move back to the tundra four to six weeks earlier than the females because of the fierce competition for territory. Their chosen nesting site – rock crevices – is a limited available habitat, so competition for the higher-quality nest sites is intense. Temperatures can still be down to -22 Fahrenheit, and food can be buried under snow, making the struggle to survive even greater. Snow buntings nesting choice provides benefits and disadvantages alike. In narrow rock cracks, the buntings have lower rates of nest predation, but it is also a very cold micro-climate for the young birds. To protect the eggs, buntings use a nest lining of feathers and fur to keep eggs and nestlings warm. Additionally, the females remain in the nest during incubation, to be fed continuously by the males. This extra parental care allows for a shorter incubation period and a higher reproductive success rate.
For those not familiar with this winter guest, it is worth pulling out the bird field guide to learn more about the appearance of this bird. When trying to view them in the area, look for those open habitats, mostly in what we would consider our agricultural areas. Be sure to bring a pair of binoculars along to enjoy this bird wonder!
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
By Susan Benson,
CNHM Director of Education
With the amount of snow we have seen in October, it seems only appropriate that the snow buntings have returned for their winter stay. We often see buntings darting away from the roadsides, similar to the juncos, but usually in larger flocks of up to 80 birds. With their white and tan colors, they blur in a flight that reminds us of a swirling snowstorm. These birds are of the Arctic, but we are fortunate to view them during our winters as they travel south.
Imagine flying south to winter in the north woods. While most migrating birds enjoy the southern United States or Central or South America, the snow bunting inhabits most of the northern parts of the United States and Canada. Buntings migrate this short distance to open habitats such as weedy or grassy fields, prairies, low mountains, sandy coastal areas, or sometimes cut-over farmland. Buntings are ground-feeders that feed on grass and other plant seeds from late fall to early spring, and seeds, buds, and insects in their breeding Arctic habitat.
As our winter transitions to spring, just like much of the bird world, the males use their coloration to attract the ladies. However, the snow bunting only has one molt each year, without the alternate plumage that we see on other birds such as the American goldfinch. After the summer molt, the male has the same white underside, brown patches on its face, with a brown and black striped back. Under their colored feather tips, the back feathers are black, and the body feathers are white. To prepare for spring, the male rubs off the brown feather tips in the snow so that he is a showy black and white by April.
These winter bunting visitors will be with us until April, when the males return to their high Arctic breeding grounds. The males move back to the tundra four to six weeks earlier than the females because of the fierce competition for territory. Their chosen nesting site – rock crevices – is a limited available habitat, so competition for the higher-quality nest sites is intense. Temperatures can still be down to -22 Fahrenheit, and food can be buried under snow, making the struggle to survive even greater. Snow buntings nesting choice provides benefits and disadvantages alike. In narrow rock cracks, the buntings have lower rates of nest predation, but it is also a very cold micro-climate for the young birds. To protect the eggs, buntings use a nest lining of feathers and fur to keep eggs and nestlings warm. Additionally, the females remain in the nest during incubation, to be fed continuously by the males. This extra parental care allows for a shorter incubation period and a higher reproductive success rate.
For those not familiar with this winter guest, it is worth pulling out the bird field guide to learn more about the appearance of this bird. When trying to view them in the area, look for those open habitats, mostly in what we would consider our agricultural areas. Be sure to bring a pair of binoculars along to enjoy this bird wonder!
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
Thursday, October 29, 2009
Tamaracks
Nature Watch
By Susan Benson,
CNHM Director of Education
Autumn Gold
The autumn gold colors of the tamaracks that greeted us this past week have been a joy to see. Although the tamarack tree resembles other evergreens, it is actually a deciduous conifer, so it sheds its needles every fall. It grows in cold, wet, poorly drained sites such as swamps, sphagnum bogs, and occasionally in upland soils. The pale green needles are soft, about one inch long, and grow in brush-like tufts along the twig. In the fall, just before the needles drop, they turn a beautiful golden color, providing a striking contrast to the last of the fall foliage.
Tamaracks have some other interesting characteristics. Their life expectancy is up to 180 years. They are cold tolerant and able to survive temperatures down to at least -85 Fahrenheit. The tree casts a light shade, so tends to have a dense undergrowth of shrubs with speckled alder, willows, red-osier dogwood, Labrador-tea, bog-rosemary, leatherleaf, or blueberries growing beneath. Because of its intolerance to shade, tamarack stands are usually even-aged.
The life cycle of a tamarack is appealing. In a bog, a tamarack tree is usually the pioneer, the first tree to establish itself in the sphagnum moss mat floating over the water.
It leafs off in the early spring before the ground has thawed, and takes four to six weeks for the needles to develop. In open areas, tamaracks can begin seed production when they are fifteen years old, but most pine cone crops come from trees that are 50 to 150 year old trees. One tree can produce as many as 20,000 cones in a good year, which can happen every three to six years. They can also produce root sprouts up to thirty feet from the parent tree. In mid-October the needles begin to change color. By the end of October, most of the seeds have dispersed, primarily through wind, but also by red squirrels forgotten caches. Most wind-dispersed seeds fall within two tree heights of the parent tree.
Animals interact closely with the tamarack tree. It is estimated that due to the consumption of seed off the ground, half of the crop is destroyed. Red squirrels cut and cache the cones for later eating. Mice, voles and shrews consume large numbers of seeds off the ground. Pine siskins and crossbills eat the seeds. By the time bacteria and fungi have “fed” off the seeds, it is thought that only about four to five percent of the seed that reaches the ground actually germinates. Additionally, snowshoe hares feed on twigs and bark, porcupines on inner bark. Ospreys sometimes choose to rest in dead tamarack, as do bald eagles on occasion.
Tamarack trees have an interesting natural and human history. Following the last ice age, it was one of the earliest species, along with spruce, to follow the retreating ice northward. Native Americans used the roots for cordage, the wood for arrow shafts, and the bark for medicine. Roots were used for sewing canoe edges. Early Americans used soft needles for stuffing pillows and mattresses. The wood was used widely for ship building, for timbers, planking, and to join the ribs to the deck timbers. The inner bark was used to treat melancholy, and the bark contains tannin that has been used for tanning leather.
Tamaracks seem to be sitting on the fence when it comes to deciding whether to be categorized as a conifer or a deciduous hardwood, and certainly cannot be called an “evergreen.” Regardless, we continue to benefit from their autumn beauty.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
By Susan Benson,
CNHM Director of Education
Autumn Gold
The autumn gold colors of the tamaracks that greeted us this past week have been a joy to see. Although the tamarack tree resembles other evergreens, it is actually a deciduous conifer, so it sheds its needles every fall. It grows in cold, wet, poorly drained sites such as swamps, sphagnum bogs, and occasionally in upland soils. The pale green needles are soft, about one inch long, and grow in brush-like tufts along the twig. In the fall, just before the needles drop, they turn a beautiful golden color, providing a striking contrast to the last of the fall foliage.
Tamaracks have some other interesting characteristics. Their life expectancy is up to 180 years. They are cold tolerant and able to survive temperatures down to at least -85 Fahrenheit. The tree casts a light shade, so tends to have a dense undergrowth of shrubs with speckled alder, willows, red-osier dogwood, Labrador-tea, bog-rosemary, leatherleaf, or blueberries growing beneath. Because of its intolerance to shade, tamarack stands are usually even-aged.
The life cycle of a tamarack is appealing. In a bog, a tamarack tree is usually the pioneer, the first tree to establish itself in the sphagnum moss mat floating over the water.
It leafs off in the early spring before the ground has thawed, and takes four to six weeks for the needles to develop. In open areas, tamaracks can begin seed production when they are fifteen years old, but most pine cone crops come from trees that are 50 to 150 year old trees. One tree can produce as many as 20,000 cones in a good year, which can happen every three to six years. They can also produce root sprouts up to thirty feet from the parent tree. In mid-October the needles begin to change color. By the end of October, most of the seeds have dispersed, primarily through wind, but also by red squirrels forgotten caches. Most wind-dispersed seeds fall within two tree heights of the parent tree.
Animals interact closely with the tamarack tree. It is estimated that due to the consumption of seed off the ground, half of the crop is destroyed. Red squirrels cut and cache the cones for later eating. Mice, voles and shrews consume large numbers of seeds off the ground. Pine siskins and crossbills eat the seeds. By the time bacteria and fungi have “fed” off the seeds, it is thought that only about four to five percent of the seed that reaches the ground actually germinates. Additionally, snowshoe hares feed on twigs and bark, porcupines on inner bark. Ospreys sometimes choose to rest in dead tamarack, as do bald eagles on occasion.
Tamarack trees have an interesting natural and human history. Following the last ice age, it was one of the earliest species, along with spruce, to follow the retreating ice northward. Native Americans used the roots for cordage, the wood for arrow shafts, and the bark for medicine. Roots were used for sewing canoe edges. Early Americans used soft needles for stuffing pillows and mattresses. The wood was used widely for ship building, for timbers, planking, and to join the ribs to the deck timbers. The inner bark was used to treat melancholy, and the bark contains tannin that has been used for tanning leather.
Tamaracks seem to be sitting on the fence when it comes to deciding whether to be categorized as a conifer or a deciduous hardwood, and certainly cannot be called an “evergreen.” Regardless, we continue to benefit from their autumn beauty.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
Thursday, October 22, 2009
Dark-Eyed Juncos
Nature Watch
By Susan Benson,
CNHM Director of Education
Driving along the road this past week, I was greeted by the white flash of tail feathers from a quickly departing flock of birds from the roadway. Many of us have probably observed that each flock flies away from the road, and often lands back on the road behind us as we travel along. This spark of color belongs to the dark-eyed junco, one of the most common birds found in North America. For northern Wisconsin, a junco is a year-round resident, but juncos still migrate from Canada to disperse throughout much of North America during the winter. As they migrate, they are often observed scavenging seeds along the roadsides. The flash of color we see as they fly occurs as they pump their tail to show their white outer tail feathers. Their coloring mimics a winter scene with its dark gray above and snow white below. We can also enjoy these birds in other places as well, on woodland walks or at our bird feeders.
Juncos are primarily seed-eaters, feeding on many plants we might be familiar with – lamb’s quarters, chickweed, and sorrel, which make up three-quarters of their diet. They are one of the few bird species that usually prefer millet and cracked corn over sunflower seeds. In the spring, they often add insects such as caterpillars, beetles, moths, ants, and flies to their diet.
When foraging, dark-eyed juncos are seen hopping along the ground, scratching like a chicken at the leaf litter, or sometimes maneuvering successfully through low, tangled undergrowth to find food. During the summer males are very territorial, but in winter, they form large flocks of ten to thirty birds that can also include several other sparrows. Junco flocks have a “pecking order,” as early migrants have a higher status than later arrivals.
If you see a bird flock and are interested in identifying the dark-eyed junco or other species, grab a bird field guide and try to identify white-throated, white-crowned, chipping, or American tree sparrows. Also, don’t be surprised if what you first think is a junco or other sparrow is actually a yellow-rumped warbler, as they are one of the other last migrants to leave our area. Migrate yourself outdoors to discover what birds you can find!
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
By Susan Benson,
CNHM Director of Education
Driving along the road this past week, I was greeted by the white flash of tail feathers from a quickly departing flock of birds from the roadway. Many of us have probably observed that each flock flies away from the road, and often lands back on the road behind us as we travel along. This spark of color belongs to the dark-eyed junco, one of the most common birds found in North America. For northern Wisconsin, a junco is a year-round resident, but juncos still migrate from Canada to disperse throughout much of North America during the winter. As they migrate, they are often observed scavenging seeds along the roadsides. The flash of color we see as they fly occurs as they pump their tail to show their white outer tail feathers. Their coloring mimics a winter scene with its dark gray above and snow white below. We can also enjoy these birds in other places as well, on woodland walks or at our bird feeders.
Juncos are primarily seed-eaters, feeding on many plants we might be familiar with – lamb’s quarters, chickweed, and sorrel, which make up three-quarters of their diet. They are one of the few bird species that usually prefer millet and cracked corn over sunflower seeds. In the spring, they often add insects such as caterpillars, beetles, moths, ants, and flies to their diet.
When foraging, dark-eyed juncos are seen hopping along the ground, scratching like a chicken at the leaf litter, or sometimes maneuvering successfully through low, tangled undergrowth to find food. During the summer males are very territorial, but in winter, they form large flocks of ten to thirty birds that can also include several other sparrows. Junco flocks have a “pecking order,” as early migrants have a higher status than later arrivals.
If you see a bird flock and are interested in identifying the dark-eyed junco or other species, grab a bird field guide and try to identify white-throated, white-crowned, chipping, or American tree sparrows. Also, don’t be surprised if what you first think is a junco or other sparrow is actually a yellow-rumped warbler, as they are one of the other last migrants to leave our area. Migrate yourself outdoors to discover what birds you can find!
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
Thursday, October 15, 2009
Goose Music
Nature Watch
By Susan Benson,
CNHM Director of Education
Goose Music
Almost daily it occurred this past week – the honk of a flight of geese in their migration flight, their voices in constant contact—what Aldo Leopold called “goose music.” Most flocks can number thirty to one hundred birds as they travel up to forty miles per hour at an altitude of 2,000 up to 30,000 feet. It is a sight everyone is used to seeing across the country and is a sound almost everyone knows. Canada geese are amazing birds that have been studied by scientists for many years.
Historically, it was a shock to many scientists to discover that many species migrated. Some naturalists felt it was impossible for tiny birds to fly so far without help. They conceived the idea that larger species, such as cranes, storks and geese, would carry these smaller birds as “living freight.” Some Native American tribes in the Western Hemisphere held beliefs that hummingbirds would ride on the backs of geese. Today, scientific study has taught us much about Canada geese and their success in migration.
Preparation for migration begins from the moment Canada geese hatch. Adult males begin molting right after mating, and the females begin five weeks after the goslings hatch. The adults re-grow their flight feathers and are ready to fly at about the same time as the goslings are able to learn - at nine weeks old. The parents teach them to fly, usually running along the surface of the water or ground for takeoff. As soon as the young are strong enough for the trip, the family begins their migration south. The young learn the migration routes from their parents and follow the same route in future years. Then the familiar v-shaped formation flight pattern begins.
Why do geese fly in a v-formation? Because it is hard to fly in an s-shape. Just kidding. In reality, the v-shape requires less energy, allowing the geese to fly longer distances. By flying slightly above the bird in front of them, there is a reduction in wind resistance. Geese can use fifty to seventy percent less energy due to the lead bird’s updraft. They can also travel at least seventy percent further than when flying alone. The larger, stronger birds are usually the leader. The lead birds rotate in a timely fashion to keep fatigue from occurring among the flight members. While flying in the v-formation, they can also communicate easier, and keep visual contact with each other.
Why are geese so loud when honking while in flight? It is believed that they are “cheerleading,” encouraging the leaders to keep up the good leadership, and to keep going! When they do travel, Canada geese stay in family groups. When ready to feed and rest, they land in familiar marshes or fields. When a large flock of geese comes in for a landing, family units “peel” off in smaller groups before they land. The next morning the arduous flight to central or southern United States continues.
It is amazing that geese, or any birds, continue to make the migration south with all the challenges they can face. When cloudy, birds may fly closer to the ground. They can have troubles with exhaustion from long flight with not enough rest. Bad weather such as snowstorms, thick fog, or strong winds can impact their success. Starvation from not enough food can occur. They can also fly into human obstructions or be shot by hunters. As we wish for their success in the coming days, we can continue to enjoy their goose music and flight overhead, soon to be a sound that will disappear until spring.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
By Susan Benson,
CNHM Director of Education
Goose Music
Almost daily it occurred this past week – the honk of a flight of geese in their migration flight, their voices in constant contact—what Aldo Leopold called “goose music.” Most flocks can number thirty to one hundred birds as they travel up to forty miles per hour at an altitude of 2,000 up to 30,000 feet. It is a sight everyone is used to seeing across the country and is a sound almost everyone knows. Canada geese are amazing birds that have been studied by scientists for many years.
Historically, it was a shock to many scientists to discover that many species migrated. Some naturalists felt it was impossible for tiny birds to fly so far without help. They conceived the idea that larger species, such as cranes, storks and geese, would carry these smaller birds as “living freight.” Some Native American tribes in the Western Hemisphere held beliefs that hummingbirds would ride on the backs of geese. Today, scientific study has taught us much about Canada geese and their success in migration.
Preparation for migration begins from the moment Canada geese hatch. Adult males begin molting right after mating, and the females begin five weeks after the goslings hatch. The adults re-grow their flight feathers and are ready to fly at about the same time as the goslings are able to learn - at nine weeks old. The parents teach them to fly, usually running along the surface of the water or ground for takeoff. As soon as the young are strong enough for the trip, the family begins their migration south. The young learn the migration routes from their parents and follow the same route in future years. Then the familiar v-shaped formation flight pattern begins.
Why do geese fly in a v-formation? Because it is hard to fly in an s-shape. Just kidding. In reality, the v-shape requires less energy, allowing the geese to fly longer distances. By flying slightly above the bird in front of them, there is a reduction in wind resistance. Geese can use fifty to seventy percent less energy due to the lead bird’s updraft. They can also travel at least seventy percent further than when flying alone. The larger, stronger birds are usually the leader. The lead birds rotate in a timely fashion to keep fatigue from occurring among the flight members. While flying in the v-formation, they can also communicate easier, and keep visual contact with each other.
Why are geese so loud when honking while in flight? It is believed that they are “cheerleading,” encouraging the leaders to keep up the good leadership, and to keep going! When they do travel, Canada geese stay in family groups. When ready to feed and rest, they land in familiar marshes or fields. When a large flock of geese comes in for a landing, family units “peel” off in smaller groups before they land. The next morning the arduous flight to central or southern United States continues.
It is amazing that geese, or any birds, continue to make the migration south with all the challenges they can face. When cloudy, birds may fly closer to the ground. They can have troubles with exhaustion from long flight with not enough rest. Bad weather such as snowstorms, thick fog, or strong winds can impact their success. Starvation from not enough food can occur. They can also fly into human obstructions or be shot by hunters. As we wish for their success in the coming days, we can continue to enjoy their goose music and flight overhead, soon to be a sound that will disappear until spring.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about exhibits and programs.
Thursday, October 8, 2009
Bird Migration
By Susan Benson,
CNHM Director of Education
It is estimated that as many as five billion birds migrate through the Americas every year. Approximately two-thirds of all North American bird species migrate. This means they travel from a breeding area to a wintering area and back again. They eat more food to gain fat for the flight. They molt old feathers, growing new ones. Many of these birds travel thousands of miles. They have no GPS or maps to navigate through the sky. The migration is timed so that young hatch as spring and fall berries and seeds ripen and insects arrive or decline. Finally, think of the ruby-throated hummingbird alone, whose weight is that of a penny, is about three inches in length, and makes a flight trek of thousands of miles while keeping a course through winds and weather. Bird migration is truly one of nature’s annual wonders.
Most scientists believe that birds navigate using the sun or stars as a compass. Some believe there is a chemical, a molecule called a superoxide, in birds’ eyes that allows them to sense the Earth’s magnetic lines as if there were a highway through the sky. Others believe the iron-rich magnetite crystals found in many birds’ brains allow them to detect the magnetic fields. Using visual landmarks, making mental maps, using olfactory cues, or genetic or environmental influences may also be amazing factors that help birds succeed with navigation and orientation.
Migrating birds generally move from north to south and from south to north. However, there are several birds that migrate over regular routes diagonally or even east to west before arrive at their destination. These diagonal travelers usually move only to the lower edge of their summer range in winter, travel east-west to a sea coast, or simply move to a lower altitude in the same place.
In late summer, before migration, the metabolism of migratory birds undergoes extreme changes. The actions of the hormones prolactin and corticosterone cause migratory birds to accumulate large amounts of fat under the skin. These accumulations provide energy for long flights.
Some birds migrate during the night to avoid predators and to eat and rest during the day. Nocturnal migrants will utter sharp and melodious peeping and piping calls, allowing individuals to stay in touch with each other.
Each bird creates behind it a small area of disturbed air during flight. Birds have learned to use this air to their advantage during migration. Air lost over the wing tips creates a spiral vortex behind each wing tip, with upswelling air on the outer side of each wing. Birds that migrate together fly aside or slightly above the bird in front and use less energy.
Migration is a very strenuous activity that requires extreme amounts of energy. Some birds will fly four to six days straight without any rest. Some researchers estimate that an equivalent feat would be similar for a human to run four-minute miles for a total of eighty hours!
We may never discover the scientific mysteries of the phenomenon of this annual cycle. Keeping a bird journal can help us learn a little more about our feathered friends. Record observations on a calendar and jot down some notes. Include any other observations of these birds. Perhaps you will discover a clue to solve the mystery of migration.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470
CNHM Director of Education
It is estimated that as many as five billion birds migrate through the Americas every year. Approximately two-thirds of all North American bird species migrate. This means they travel from a breeding area to a wintering area and back again. They eat more food to gain fat for the flight. They molt old feathers, growing new ones. Many of these birds travel thousands of miles. They have no GPS or maps to navigate through the sky. The migration is timed so that young hatch as spring and fall berries and seeds ripen and insects arrive or decline. Finally, think of the ruby-throated hummingbird alone, whose weight is that of a penny, is about three inches in length, and makes a flight trek of thousands of miles while keeping a course through winds and weather. Bird migration is truly one of nature’s annual wonders.
Most scientists believe that birds navigate using the sun or stars as a compass. Some believe there is a chemical, a molecule called a superoxide, in birds’ eyes that allows them to sense the Earth’s magnetic lines as if there were a highway through the sky. Others believe the iron-rich magnetite crystals found in many birds’ brains allow them to detect the magnetic fields. Using visual landmarks, making mental maps, using olfactory cues, or genetic or environmental influences may also be amazing factors that help birds succeed with navigation and orientation.
Migrating birds generally move from north to south and from south to north. However, there are several birds that migrate over regular routes diagonally or even east to west before arrive at their destination. These diagonal travelers usually move only to the lower edge of their summer range in winter, travel east-west to a sea coast, or simply move to a lower altitude in the same place.
In late summer, before migration, the metabolism of migratory birds undergoes extreme changes. The actions of the hormones prolactin and corticosterone cause migratory birds to accumulate large amounts of fat under the skin. These accumulations provide energy for long flights.
Some birds migrate during the night to avoid predators and to eat and rest during the day. Nocturnal migrants will utter sharp and melodious peeping and piping calls, allowing individuals to stay in touch with each other.
Each bird creates behind it a small area of disturbed air during flight. Birds have learned to use this air to their advantage during migration. Air lost over the wing tips creates a spiral vortex behind each wing tip, with upswelling air on the outer side of each wing. Birds that migrate together fly aside or slightly above the bird in front and use less energy.
Migration is a very strenuous activity that requires extreme amounts of energy. Some birds will fly four to six days straight without any rest. Some researchers estimate that an equivalent feat would be similar for a human to run four-minute miles for a total of eighty hours!
We may never discover the scientific mysteries of the phenomenon of this annual cycle. Keeping a bird journal can help us learn a little more about our feathered friends. Record observations on a calendar and jot down some notes. Include any other observations of these birds. Perhaps you will discover a clue to solve the mystery of migration.
For 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 exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470
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