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.
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