Susan Benson,
CNHM Director of Education
Could there be anything more perfect than a nuthatch? I sat this morning for a few moments of solitude, in front of the new bird feeder, watching the red-breasted nuthatches visit the sunflower seed feeder. Having it three feet away from my window made for such up-close inspection as I sat, without moving. I watched as it tossed away the seeds to the ground, amazing me with its beauty. I live in the perfect habitat for red-breasted nuthatches, a mixed deciduous-coniferous forest, with mature stands of decaying large trees. I knew these monogamous birds stay paired up throughout the winter. Then, as I watched it eat from further away, I thought of its appropriate name. The common name, nuthatch, comes from the Eurasian Nuthatch's habit of wedging an acorn into a bark crevice and then breaking it open with blows from its bill. The nuthatch family name is Sittidae, and sitte is a Greek word for "birds that peck on the bark of trees." These are just some of the interesting facts about this well-loved bird.
When building their nests, both male and female red-breasted nuthatches excavate a hole that can take up to 18 days to build. They are known to steal the soft lining from other birds’ nests for their own. Then they repeatedly smear pine pitch and insects around the entrance of their nest to sanitize it. To apply the pitch, they use their beak or a piece of bark with the pitch on it as an application tool. The males will place the resin on the outside, and females place it on the inside. It is believed that the pitch and defensive chemicals of the insects keeps out parasites. It might also discourage predators. The birds prevent it from sticking to themselves by diving right through the hole. It is dead or dying aspens that these birds prefer for their excavations because of the soft wood.
In summer, red-breasted nuthatches eat beetles, caterpillars, spiders, ants, and earwigs, and they raise their young on 100% protein. In fall and winter they tend to eat conifer seeds. They will transport cone seeds from a heavily laden conifer and hoard excess food in nearby larders to help them get through winter. They shove the food into bark crevices and cover them with pieces of bark, lichen or pebbles. Red-breasted nuthatches also eat from bird feeders, often choosing the heaviest food item available, jamming it into bark and hammering it open.
Red-breasted nuthatches have interesting behaviors. One of most comical behaviors to watch is the typical nuthatch movement. Red-breasted nuthatches move quickly on trees, zigzagging downward, relying on their backward-pointing toe to grip the trunk. This advantage helps them see insects hiding in crevices that woodpeckers and birds that only move upward on a tree cannot see. Another behavior seen mostly in winter is when red-breasted nuthatches join foraging flocks of chickadees and other small birds. Also, small groups of nuthatches will spend the night together in tree cavities. Finally, when listening, their call is a “yank, yank” that sounds a bit like a high-pitched tin trumpet.
Did you know that due to the weaker feet of a red-breasted nuthatch, they bathe by puffing their wings out during a rain storm? This is just one more fact I couldn’t leave out, so I end with that nature nugget. I can think of no reason that we shouldn’t all be nuts for nuthatches!
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.
Wednesday, January 27, 2010
Thursday, January 21, 2010
Subnivean Temperatures
Nature Watch
By Susan Benson,
CNHM Director of Education
The subnivean space – perhaps it sounds like something out of a science fiction novel, something you might find on a journey to the center of the earth. However, it is not as mystifying as one might think. Quite simply, the subnivean space is the layer between the ground and snowpack. While the snow cover builds up, the ground gives off heat, creating water vapor that condenses and freezes under the bottom layer of snow, creating small spaces at ground level. Many small animals would never survive the winter cold without this space.
The minute a snowflake falls, it begins changing its shape. It can be affected by the internal snowpack characteristics and the external weather conditions. The first deterioration of a snowflake begins as a “destructive” change, in which the snow grains become more rounded. The unequal temperature distribution in the snowpack causes the water molecules to melt, changing the radiating arms of the snowflakes into a rough, spherical ice particle. These ice grains can then connect together, until they are roughly the same size. This metamorphosis occurs more quickly when air temperature is warmer, and is also influenced by wind or the weight of the snow above. It is this destructive metamorphosis that makes building snow shelters so effective.
The snowpack also is exposed to constructive metamorphosis, a process in which the temperature changes from the bottom to top of the snowpack is significantly different. The snow’s upper part is affected by the air temperature, and the lower part is warmed by the ground. Heat is conducted very slowly upward through the snow, affecting the water vapor distribution, and creating a 100% relative humidity in many of the air spaces in the snow. This process causes the ice crystals at the bottom of the snowpack to get continually smaller. Eventually, they form “depth hoar,” brittle, loosely arranged crystals that create easy movement for small mammals as they search for food under the winter snow.
The third factor which affects snow is the “melt metamorphosis”, in which happens when the snowpack is impacted by above freezing temperatures. Surface snow melt percolates down through the snowpack, encounters lower temperatures, and refreezes. As it freezes, it releases heat, bringing the entire snowpack to a more equal temperature. Rain and fog can also cause a similar effect.
Doesn’t the sun’s solar radiation warm the snowpack as well? We all know that spending a day in the snow in bright sunlight is shocking to our eyes, because snow is highly reflective of incoming solar radiation. Perhaps better than a mirror, snow reflects 75-95% of the sunlight hitting its surface. This means that a small amount of solar energy is available to raise the temperature of the snow. However, aging snow, as it accumulates dust, can decrease the sun’s reflection to as low as 45 percent.
It is easy to see that although complex processes occur, the snowpack provides amazing insulation for the winter survival of organisms. How much snow is enough? One theory is that 20 centimeters is a critical depth. The subnivean layer and its temperature and effectiveness for animal survival can also be affected by the type of snowpack metamorphosis that has occurred. By the time the snowpack reaches 40-50 centimeters, the subnivean environment temperature is almost constant.
Most importantly to our animal world, it is as if the snow peels away from the ground, leaving pockets where mice, voles, and shrews spend the winter. Some predators such as weasels live there too. Under that white snow in your yard there is an entire food chain still at work! Next time you are out for a ski, hike, or on a snowmobile trail, look at the edges of the trails to see if you can observe tunnels created by animals living in the snow.
Nature Watch is brought to you by the Cable Natural History Museum. 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 in Cable at 13470 County Highway M or on the web at www.cablemuseum.org to learn more about exhibits and programs.
By Susan Benson,
CNHM Director of Education
The subnivean space – perhaps it sounds like something out of a science fiction novel, something you might find on a journey to the center of the earth. However, it is not as mystifying as one might think. Quite simply, the subnivean space is the layer between the ground and snowpack. While the snow cover builds up, the ground gives off heat, creating water vapor that condenses and freezes under the bottom layer of snow, creating small spaces at ground level. Many small animals would never survive the winter cold without this space.
The minute a snowflake falls, it begins changing its shape. It can be affected by the internal snowpack characteristics and the external weather conditions. The first deterioration of a snowflake begins as a “destructive” change, in which the snow grains become more rounded. The unequal temperature distribution in the snowpack causes the water molecules to melt, changing the radiating arms of the snowflakes into a rough, spherical ice particle. These ice grains can then connect together, until they are roughly the same size. This metamorphosis occurs more quickly when air temperature is warmer, and is also influenced by wind or the weight of the snow above. It is this destructive metamorphosis that makes building snow shelters so effective.
The snowpack also is exposed to constructive metamorphosis, a process in which the temperature changes from the bottom to top of the snowpack is significantly different. The snow’s upper part is affected by the air temperature, and the lower part is warmed by the ground. Heat is conducted very slowly upward through the snow, affecting the water vapor distribution, and creating a 100% relative humidity in many of the air spaces in the snow. This process causes the ice crystals at the bottom of the snowpack to get continually smaller. Eventually, they form “depth hoar,” brittle, loosely arranged crystals that create easy movement for small mammals as they search for food under the winter snow.
The third factor which affects snow is the “melt metamorphosis”, in which happens when the snowpack is impacted by above freezing temperatures. Surface snow melt percolates down through the snowpack, encounters lower temperatures, and refreezes. As it freezes, it releases heat, bringing the entire snowpack to a more equal temperature. Rain and fog can also cause a similar effect.
Doesn’t the sun’s solar radiation warm the snowpack as well? We all know that spending a day in the snow in bright sunlight is shocking to our eyes, because snow is highly reflective of incoming solar radiation. Perhaps better than a mirror, snow reflects 75-95% of the sunlight hitting its surface. This means that a small amount of solar energy is available to raise the temperature of the snow. However, aging snow, as it accumulates dust, can decrease the sun’s reflection to as low as 45 percent.
It is easy to see that although complex processes occur, the snowpack provides amazing insulation for the winter survival of organisms. How much snow is enough? One theory is that 20 centimeters is a critical depth. The subnivean layer and its temperature and effectiveness for animal survival can also be affected by the type of snowpack metamorphosis that has occurred. By the time the snowpack reaches 40-50 centimeters, the subnivean environment temperature is almost constant.
Most importantly to our animal world, it is as if the snow peels away from the ground, leaving pockets where mice, voles, and shrews spend the winter. Some predators such as weasels live there too. Under that white snow in your yard there is an entire food chain still at work! Next time you are out for a ski, hike, or on a snowmobile trail, look at the edges of the trails to see if you can observe tunnels created by animals living in the snow.
Nature Watch is brought to you by the Cable Natural History Museum. 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 in Cable at 13470 County Highway M or on the web at www.cablemuseum.org to learn more about exhibits and programs.
Wednesday, January 13, 2010
Bobcats
By Susan Benson,
CNHM Director of Education
Coming home one night, I spotted yellow eyes in the road ahead. It didn't look like the same color made by white-tailed deer, so I took even closer notice. As I approached, I was excited to see a bobcat. I knew almost immediately what it was as I made those split-second decisions - the animal was about twice the size as a domestic cat, and although I couldn't see its prominent ear tufts, I caught sight of the short 'bobbed' tail that gives these cats their name. How thrilling it was to have visual evidence of these creatures around my home!
The physical attributes of bobcats vary depending on their location. Bobcats in forested northern territories are usually bigger with darker, dense fur while further south they are smaller small and have lighter coloration. Their coat takes on a reddish coloration during the warmer months, and the markings camouflage this amazing carnivore as they hunt through thick underbrush.
Despite their smaller size, bobcats are very successful predators due to their diverse food choices and adaptability. They can take down prey that are eight times their own weight, choosing first from snowshoe hare and cottontail rabbit populations. They also eat squirrels, birds, porcupines, mice, voles, shrews, birds, insects, and reptiles. Less common food sources such as deer, foxes, or skunks are used when other food is scarce. Bobcats rely on stealth, sneaking up to the prey, then using their long hind legs to produce great bursts of speed, reaching nearly thirty miles per hour. When hunting a rabbit, for example, they will often wait until a rabbit approaches within 15-35 feet, and then pounce. Such sneaky hunting tactics!
Bobcats are solitary, and mostly nocturnal, being most active at dawn and dusk. For those who search for their own bobcat discovery, bobcats prefer heavy forested areas, alder thickets or coniferous swamps. It is estimated that an average density of bobcats varies, but is about 1 bobcat every 25 square miles. Males move a distance of up to 2.6 miles per week, while females move about one mile less. They often use roads or game trails to move between food or resting places, especially in deep snow. If you have a bobcat story to share, please email the Museum at info@cablemuseum.org, or post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
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 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.
________________________________________
Cable Natural History Museum
PO Box 416
CNHM Director of Education
Coming home one night, I spotted yellow eyes in the road ahead. It didn't look like the same color made by white-tailed deer, so I took even closer notice. As I approached, I was excited to see a bobcat. I knew almost immediately what it was as I made those split-second decisions - the animal was about twice the size as a domestic cat, and although I couldn't see its prominent ear tufts, I caught sight of the short 'bobbed' tail that gives these cats their name. How thrilling it was to have visual evidence of these creatures around my home!
The physical attributes of bobcats vary depending on their location. Bobcats in forested northern territories are usually bigger with darker, dense fur while further south they are smaller small and have lighter coloration. Their coat takes on a reddish coloration during the warmer months, and the markings camouflage this amazing carnivore as they hunt through thick underbrush.
Despite their smaller size, bobcats are very successful predators due to their diverse food choices and adaptability. They can take down prey that are eight times their own weight, choosing first from snowshoe hare and cottontail rabbit populations. They also eat squirrels, birds, porcupines, mice, voles, shrews, birds, insects, and reptiles. Less common food sources such as deer, foxes, or skunks are used when other food is scarce. Bobcats rely on stealth, sneaking up to the prey, then using their long hind legs to produce great bursts of speed, reaching nearly thirty miles per hour. When hunting a rabbit, for example, they will often wait until a rabbit approaches within 15-35 feet, and then pounce. Such sneaky hunting tactics!
Bobcats are solitary, and mostly nocturnal, being most active at dawn and dusk. For those who search for their own bobcat discovery, bobcats prefer heavy forested areas, alder thickets or coniferous swamps. It is estimated that an average density of bobcats varies, but is about 1 bobcat every 25 square miles. Males move a distance of up to 2.6 miles per week, while females move about one mile less. They often use roads or game trails to move between food or resting places, especially in deep snow. If you have a bobcat story to share, please email the Museum at info@cablemuseum.org, or post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
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 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.
________________________________________
Cable Natural History Museum
PO Box 416
Thursday, January 7, 2010
Red Squirrels
Nature Watch
By Susan Benson,
CNHM Director of Education
Last week’s observation of two squirrels chasing each other around the tree brought back funny memories of my interactions with this animal. For years I had appreciated these small red critters as they scolded me with their “chuck, chuck” sounds while waving their tail and stomping their feet at me. This appreciation changed a bit when one day, while napping on my couch, I heard a noise in the kitchen. I looked with surprise, and there, on top of my refrigerator, was a red squirrel. That scolding sound took on a new meaning to me as I spent the next half hour trying to encourage this squirrel to leave the house. After a lengthy search, I still could not figure out how this squirrel found entrance to my home. The next day when I returned home from the Museum, I noticed the artwork on the walls all cockeyed – that squirrel had enjoyed another day while I was hard at work, “playing” inside my house. A few days later, I discovered the toilet paper had been unrolled and pulled all over the house by this mischievous squirrel. Its playful antics ended when I discovered its entrance through the dryer vent (clever, aren’t they?) Now I consider myself fortunate to enjoy them outside of the house.
Active mostly at dawn and late afternoon, red squirrels may spend up to eighty percent of their time foraging for food. One of their main food sources is pine seeds. In the fall, “reds” will cut green cones from trees and store them in their piles, or middens, under logs, at the base of trees, or underground. Up to a bushel of food can be stored in one of these piles. They are able to relocate their buried seeds a few inches underground and deep below the snow with their great sense of smell. However, many midden piles are not found, giving red squirrels an important role as a re-forester. Additionally, “reds” may eat up to two-thirds of a pine seed crop in an area each year. They also eat acorns, beechnuts, seeds, berries, birds’ eggs, and fungi. Red squirrels will bite into a sugar maple’s xylem, letting the sap ooze out, to return later when the water has evaporated and the sugar content is higher.
It is around this time of year when breeding for red squirrels begins, which explains the two red squirrels I observed running around the tree for a dizzying amount of time. “Red” makes its nests in a variety of places including hollows in the ground, in tree hollows, logs or crotches in trees.
Boomer, chatterbox, chickaree, and pine squirrel are just some of the names for a red squirrel. Their scientific name is Tamiasciurus hudsonicus. Tamiasciurus is Latin for “the steward who sits in the shadow of his tail,” and hudsonicus relates to Hudson Bay, where this species was first named. It is only the northern two-thirds of Wisconsin that enjoys the “chatter” of this squirrel that prefers coniferous and mixed forests. If you have your own red squirrel story to share, please email the Museum at info@cablemuseum.org, or post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
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 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
Last week’s observation of two squirrels chasing each other around the tree brought back funny memories of my interactions with this animal. For years I had appreciated these small red critters as they scolded me with their “chuck, chuck” sounds while waving their tail and stomping their feet at me. This appreciation changed a bit when one day, while napping on my couch, I heard a noise in the kitchen. I looked with surprise, and there, on top of my refrigerator, was a red squirrel. That scolding sound took on a new meaning to me as I spent the next half hour trying to encourage this squirrel to leave the house. After a lengthy search, I still could not figure out how this squirrel found entrance to my home. The next day when I returned home from the Museum, I noticed the artwork on the walls all cockeyed – that squirrel had enjoyed another day while I was hard at work, “playing” inside my house. A few days later, I discovered the toilet paper had been unrolled and pulled all over the house by this mischievous squirrel. Its playful antics ended when I discovered its entrance through the dryer vent (clever, aren’t they?) Now I consider myself fortunate to enjoy them outside of the house.
Active mostly at dawn and late afternoon, red squirrels may spend up to eighty percent of their time foraging for food. One of their main food sources is pine seeds. In the fall, “reds” will cut green cones from trees and store them in their piles, or middens, under logs, at the base of trees, or underground. Up to a bushel of food can be stored in one of these piles. They are able to relocate their buried seeds a few inches underground and deep below the snow with their great sense of smell. However, many midden piles are not found, giving red squirrels an important role as a re-forester. Additionally, “reds” may eat up to two-thirds of a pine seed crop in an area each year. They also eat acorns, beechnuts, seeds, berries, birds’ eggs, and fungi. Red squirrels will bite into a sugar maple’s xylem, letting the sap ooze out, to return later when the water has evaporated and the sugar content is higher.
It is around this time of year when breeding for red squirrels begins, which explains the two red squirrels I observed running around the tree for a dizzying amount of time. “Red” makes its nests in a variety of places including hollows in the ground, in tree hollows, logs or crotches in trees.
Boomer, chatterbox, chickaree, and pine squirrel are just some of the names for a red squirrel. Their scientific name is Tamiasciurus hudsonicus. Tamiasciurus is Latin for “the steward who sits in the shadow of his tail,” and hudsonicus relates to Hudson Bay, where this species was first named. It is only the northern two-thirds of Wisconsin that enjoys the “chatter” of this squirrel that prefers coniferous and mixed forests. If you have your own red squirrel story to share, please email the Museum at info@cablemuseum.org, or post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
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 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, December 31, 2009
Red Fox
Nature Watch
By Susan Benson,
CNHM Director of Education
Have I mentioned lately how much fun it is to live in the northwoods? I continue to be amazed by what we can see in the natural world in one or two days. On my own property, in the last week, I’ve seen wolf tracks; a bobcat, whose tracks I searched for the next day; two red squirrels chasing each other around a tree, for what seemed like a dizzying amount of time; white-tail deer tracks, everywhere; and what appears to be a red fox bed site. In a few days’ time I had the content for several weeks Nature Watch articles.
I was exploring the forest behind my house. I found the beds on a small hill, four disc-shaped beds with fox tracks leading up to them. I smiled with such pride at having found them in the forest, probably one hundred yards away from my house. I had to find out more. Was it mostly likely a red fox or gray fox? Was it one fox returning for several nights, or two? I had to know the answers.
Was it mostly likely a red fox or gray fox? Gray fox are not as common in the northern third of the state, as Wisconsin is the northern part of its range. Therefore, I assume that the bed sites were made by a red fox.
Was it one fox or two? In December, males and females have paired up in preparation of the breeding season, which means the bedding sites I viewed are possibly from two animals. Foxes sleep while curling their long bushy tails around their body and over their nose and foot pads to keep warm. Red foxes are nocturnal, with most of their hunting taking place two hours before sunset until a few hours after sunrise. Able to run up to thirty miles per hour, they can travel up to nine miles in one night in search of food.
In the winter, red fox eat mostly meadow voles, mice, snowshoe hare, and cottontail rabbits. During other seasons they will eat squirrels, songbirds, eggs, insects, snails, crayfish, berries, fruit, acorns, corn, or grass. The red fox is a solitary hunter that searches field edges or forest while search for their prey. They have excellent eyesight, as the slight movement of an ear may be all that is needed to locate a rabbit or squirrel. They can smell eggs or young rabbits in their nests. Their large ears allow them to locate a sound within one degree of its actual location. Additionally, fox can hear mouse squeals from 150 feet away, or hear movement underground, dig, and capture their prey. From a distance, they creep low to the ground, slowly towards the correct location. Once they are close enough, they will often launch themselves up at an almost forty-five degree angle, pouncing down on the site of their prey. They can jump up to fifteen feet away! They will sometimes kill more than they can eat, and will bury food for future use.
Fox families have their own marked territories that they defend from intruders, a space that is from 150-400 acres. Scenting is an important form of staking territory, as they mark rocks and trees with their urine. When facing another fox, they may participate in a group chase or will charge and growl. They wave their tail to communicate their presence. Red foxes also have a wide range of vocalizations that peak during winter during the dispersal of juveniles as they stake out new ranges, and during the mating season. They have barks used as internal family communication, as a warning, or to convey information. They have “shrieks,” “staccato barks,” and “whines” to interact with others and establish contact. They have “wow-wow” barks for friendly communication. “Coughs” warn cubs of potential danger, and “growls” and “screams” are used in defensive positions.
If you seem me on the street, please do not be surprised if I give you a “wow-wow” bark as my hello. Also please know, if I cough, it is probably due to a cold, not a warning! Be sure to spend some of your own holiday season outdoors! Who knows what you will discover in your own back yard. Be sure to include a night listening session as well. For listening to potential fox sounds, choose cold, clear winter nights when fox prefer auditory communication. If you have your own red or gray fox story to share, please email the Museum at info@cablemuseum.org, or post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
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 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
Have I mentioned lately how much fun it is to live in the northwoods? I continue to be amazed by what we can see in the natural world in one or two days. On my own property, in the last week, I’ve seen wolf tracks; a bobcat, whose tracks I searched for the next day; two red squirrels chasing each other around a tree, for what seemed like a dizzying amount of time; white-tail deer tracks, everywhere; and what appears to be a red fox bed site. In a few days’ time I had the content for several weeks Nature Watch articles.
I was exploring the forest behind my house. I found the beds on a small hill, four disc-shaped beds with fox tracks leading up to them. I smiled with such pride at having found them in the forest, probably one hundred yards away from my house. I had to find out more. Was it mostly likely a red fox or gray fox? Was it one fox returning for several nights, or two? I had to know the answers.
Was it mostly likely a red fox or gray fox? Gray fox are not as common in the northern third of the state, as Wisconsin is the northern part of its range. Therefore, I assume that the bed sites were made by a red fox.
Was it one fox or two? In December, males and females have paired up in preparation of the breeding season, which means the bedding sites I viewed are possibly from two animals. Foxes sleep while curling their long bushy tails around their body and over their nose and foot pads to keep warm. Red foxes are nocturnal, with most of their hunting taking place two hours before sunset until a few hours after sunrise. Able to run up to thirty miles per hour, they can travel up to nine miles in one night in search of food.
In the winter, red fox eat mostly meadow voles, mice, snowshoe hare, and cottontail rabbits. During other seasons they will eat squirrels, songbirds, eggs, insects, snails, crayfish, berries, fruit, acorns, corn, or grass. The red fox is a solitary hunter that searches field edges or forest while search for their prey. They have excellent eyesight, as the slight movement of an ear may be all that is needed to locate a rabbit or squirrel. They can smell eggs or young rabbits in their nests. Their large ears allow them to locate a sound within one degree of its actual location. Additionally, fox can hear mouse squeals from 150 feet away, or hear movement underground, dig, and capture their prey. From a distance, they creep low to the ground, slowly towards the correct location. Once they are close enough, they will often launch themselves up at an almost forty-five degree angle, pouncing down on the site of their prey. They can jump up to fifteen feet away! They will sometimes kill more than they can eat, and will bury food for future use.
Fox families have their own marked territories that they defend from intruders, a space that is from 150-400 acres. Scenting is an important form of staking territory, as they mark rocks and trees with their urine. When facing another fox, they may participate in a group chase or will charge and growl. They wave their tail to communicate their presence. Red foxes also have a wide range of vocalizations that peak during winter during the dispersal of juveniles as they stake out new ranges, and during the mating season. They have barks used as internal family communication, as a warning, or to convey information. They have “shrieks,” “staccato barks,” and “whines” to interact with others and establish contact. They have “wow-wow” barks for friendly communication. “Coughs” warn cubs of potential danger, and “growls” and “screams” are used in defensive positions.
If you seem me on the street, please do not be surprised if I give you a “wow-wow” bark as my hello. Also please know, if I cough, it is probably due to a cold, not a warning! Be sure to spend some of your own holiday season outdoors! Who knows what you will discover in your own back yard. Be sure to include a night listening session as well. For listening to potential fox sounds, choose cold, clear winter nights when fox prefer auditory communication. If you have your own red or gray fox story to share, please email the Museum at info@cablemuseum.org, or post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.
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 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, December 24, 2009
Bird Coloration
Nature Watch
By Susan Benson,
CNHM Director of Education
A blue jay darts across the yard. An American goldfinch shows its more camouflaged winter colors that are so drastically different than the summer yellow and black. Even the black and whit e of a chickadee against the snow is a striking color contrast. Color is not always what it seems in the bird world, in spite of the amazing variety of colors we see. Still, it seems to bring a gasp of pleasure when we see these colored wonders.
For most birds, color comes from pigment, which are chemical compounds located in the feathers or skin. Pigments absorb part of the white sunlight as it hits, and then reflect just part of the color spectrum, which is what the observer’s eye sees. For example, a cardinal has pigment that absorbs all the wavelengths of light except the ones that, when they enter our retina receptors, appear red. When we see black color, no light is reflected. When we see white color, all wavelengths are reflected. Melanin pigments produce blacks, browns, grays, and beige colored feathers. The pigments that produce yellows, reds, and oranges are called carotenoid pigments. These carotenoids are not produced within the bird’s body, however. Birds of these colors rely on their food – pink flamingos depend on carotenoid-rich crustaceans for their color, and the yellow goldfinches get their pigmentation from seeds they eat.
The blue of a jay that we see is not coloration based on pigments. In fact, blue and iridescent colors are "structural colors," produced in special cells in the feather barbs. For us to see “blue,” there are microscopic box-shaped cells that scatter the light, favoring the shorter blue wavelengths. Iridescent colors are produced by from modified barbules that cause wavelength changes based on the angle of reflection. These special cells split the sunlight, making iridescent colors dependent on the angle of the light. A ruby-throated hummingbird aligned just right makes a shimmering sight, but when turned wrong, the color goes black.
Many of our camouflaged birds exhibit what is known as "countershading.” These birds have dark backs with gradual lighter shading until the belly is white. Countershading tends to eliminate an abrupt shadow, absorbing bright light from above while reflecting light below where light is dim. “Disruptive coloration” is the use of patterns that break up the outline of the bird to avoid detection. Killdeers are an excellent example of this disruption, allowing the bird to blend in with the color of its background.
Why is coloration important? The earliest theory made by Darwin regarding bird coloration was that the bright coloration of males evolved through female choice of the most attractive male plumage. Another “color” theory is that bright colors can intimidate predators. Or, if we consider the bright coloration some species, such as monarch butterflies or coral snakes use to warn predators, it could be that the more colorful the bird the more unpalatable. It is believed that birds identify themselves to other flock members through color patterns visible in flight. Bright colors might help to deflect predator’s attention away from nesting sites. Colors inside of mouths of open chicks may stimulate parental feeding and help guide them to where “x marks the spot.” These are all interesting examples of how birds use their coloration.
Perhaps bird songs did not evolve for our human enjoyment, nor did bird colors evolve to delight our eyes. In spite of this, we benefit greatly from the joy they bring. Millions of dollars are spent every year as humans attempt to draw them closer to their homes. Birds are a part of many people’s regular conversation. We even bring their sounds and bright colors into our homes as pets. Whatever their color, they are an integral part of our human lives.
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
A blue jay darts across the yard. An American goldfinch shows its more camouflaged winter colors that are so drastically different than the summer yellow and black. Even the black and whit e of a chickadee against the snow is a striking color contrast. Color is not always what it seems in the bird world, in spite of the amazing variety of colors we see. Still, it seems to bring a gasp of pleasure when we see these colored wonders.
For most birds, color comes from pigment, which are chemical compounds located in the feathers or skin. Pigments absorb part of the white sunlight as it hits, and then reflect just part of the color spectrum, which is what the observer’s eye sees. For example, a cardinal has pigment that absorbs all the wavelengths of light except the ones that, when they enter our retina receptors, appear red. When we see black color, no light is reflected. When we see white color, all wavelengths are reflected. Melanin pigments produce blacks, browns, grays, and beige colored feathers. The pigments that produce yellows, reds, and oranges are called carotenoid pigments. These carotenoids are not produced within the bird’s body, however. Birds of these colors rely on their food – pink flamingos depend on carotenoid-rich crustaceans for their color, and the yellow goldfinches get their pigmentation from seeds they eat.
The blue of a jay that we see is not coloration based on pigments. In fact, blue and iridescent colors are "structural colors," produced in special cells in the feather barbs. For us to see “blue,” there are microscopic box-shaped cells that scatter the light, favoring the shorter blue wavelengths. Iridescent colors are produced by from modified barbules that cause wavelength changes based on the angle of reflection. These special cells split the sunlight, making iridescent colors dependent on the angle of the light. A ruby-throated hummingbird aligned just right makes a shimmering sight, but when turned wrong, the color goes black.
Many of our camouflaged birds exhibit what is known as "countershading.” These birds have dark backs with gradual lighter shading until the belly is white. Countershading tends to eliminate an abrupt shadow, absorbing bright light from above while reflecting light below where light is dim. “Disruptive coloration” is the use of patterns that break up the outline of the bird to avoid detection. Killdeers are an excellent example of this disruption, allowing the bird to blend in with the color of its background.
Why is coloration important? The earliest theory made by Darwin regarding bird coloration was that the bright coloration of males evolved through female choice of the most attractive male plumage. Another “color” theory is that bright colors can intimidate predators. Or, if we consider the bright coloration some species, such as monarch butterflies or coral snakes use to warn predators, it could be that the more colorful the bird the more unpalatable. It is believed that birds identify themselves to other flock members through color patterns visible in flight. Bright colors might help to deflect predator’s attention away from nesting sites. Colors inside of mouths of open chicks may stimulate parental feeding and help guide them to where “x marks the spot.” These are all interesting examples of how birds use their coloration.
Perhaps bird songs did not evolve for our human enjoyment, nor did bird colors evolve to delight our eyes. In spite of this, we benefit greatly from the joy they bring. Millions of dollars are spent every year as humans attempt to draw them closer to their homes. Birds are a part of many people’s regular conversation. We even bring their sounds and bright colors into our homes as pets. Whatever their color, they are an integral part of our human lives.
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, December 17, 2009
What do they do for Christmas?
Nature Watch
By Susan Benson,
CNHM Director of Education
While I watched students in a classroom writing their letters to Santa, I began to think about how different animals spend their Christmas. Where do the birds go? What about the frogs or turtles? Are the black bears already hibernating? What kind of “Christmas” do they have?
Where do some of the birds go for Christmas? For this answer, I had to go to my favorite bird field guides. The common loon leaves our lakes to enjoy the eastern and gulf coast, as well as the south-eastern part of the United States. Banded great blue herons from Canada have been found in Mexico, Honduras, Cuba, Colombia, Venezuela, and Ecuador’s Galapagos Islands. Some of my favorite forest-loving birds have just the right idea – red-eyed vireos end up in the western Amazon, hermit thrushes in the Bahamas, Guatemala, or El Salvador, and the black-throated green warbler in the Bahamas, Cuba, Jamaica, or Panama. The northern oriole heads to central Mexico or northern South America. Finally, the winter wren (how does it get that name anyway?) winters in the southern United States.
If we take a look at bald eagles of the Great Lakes region, they do not always migrate, though these resident eagles may travel significant distances in winter to seek food. Ruffed grouse stay with us, growing fringes on their toes in the winter to act like natural snowshoes and spending cold nights using the snow as insulation – imagine using the snow to stay warm. Next we can look at the resident bird that carries a bit of Christmas red color, the pileated woodpecker. These birds make deep, oval excavations in trees to find ants, especially carpenter ants, and wood-boring beetle larvae. These woodpeckers apparently have the “spirit of giving” year-round, as their large excavations often become feeding stations for other woodpeckers, wrens, or other birds.
Frogs have an interesting Christmas. Wood frogs, for example have no heartbeat. They do not breathe. Their blood does not circulate. Their nerves barely register electrical impulses. They are essentially frozen solid, yet their vital organs are not damaged. Spring peepers, gray tree frogs and upland chorus frogs also may freeze and thaw several times during the course of a winter. How do they do it? The answer is antifreeze. When ice begins to form on a wood frog’s skin, the frog’s liver releases a high level of blood sugar, enough to fill the blood vessels in all vital organs, creating a type of antifreeze. Other frogs will burrow into the soil or a lake bed to keep from freezing. Leopard frogs sink to the bottom of a water body, where they sometimes unfortunately become food for a fish.
Where do turtles go in the winter? All but one of Wisconsin's eleven turtle species spend Christmas under water. A few turtles bury themselves while others remain motionless on the bottom. Some scientists believe that they hibernate, their blood changing to function like antifreeze, with their body temperature dropping to only a few degrees above freezing. Other scientists believe that they don’t hibernate, but are semi-active, although this activity can take a toll on their body reserves.
When do black bears go into hibernation? Do they nestle in their beds for a long winter’s sleep? Technically, bears go into torpor, which is a state of reduced metabolism from which they can be awakened. Male black bears don’t always go into dens, sleeping right on the ground, or under downed treetops. These males can be more easily aroused from their “winter’s sleep.” When you add the fact that there are a lot of humans moving around in the forest during our fall hunting season, and combine it with the current feeding and baiting of deer or other animals, it is possible to see signs of bears even through November. The latest I have seen bear tracks in the snow is December 13, although most female black bears can go into torpor as early as October first.
As I wrap my presents, enjoy my lit tree, and huddle inside my warm house, waiting for a holiday season, I again find a renewed sense of wonder at the natural world. How fortunate we are to be able to enjoy this variety of wildlife all year round, no matter what the season or conditions in which we find ourselves.
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
While I watched students in a classroom writing their letters to Santa, I began to think about how different animals spend their Christmas. Where do the birds go? What about the frogs or turtles? Are the black bears already hibernating? What kind of “Christmas” do they have?
Where do some of the birds go for Christmas? For this answer, I had to go to my favorite bird field guides. The common loon leaves our lakes to enjoy the eastern and gulf coast, as well as the south-eastern part of the United States. Banded great blue herons from Canada have been found in Mexico, Honduras, Cuba, Colombia, Venezuela, and Ecuador’s Galapagos Islands. Some of my favorite forest-loving birds have just the right idea – red-eyed vireos end up in the western Amazon, hermit thrushes in the Bahamas, Guatemala, or El Salvador, and the black-throated green warbler in the Bahamas, Cuba, Jamaica, or Panama. The northern oriole heads to central Mexico or northern South America. Finally, the winter wren (how does it get that name anyway?) winters in the southern United States.
If we take a look at bald eagles of the Great Lakes region, they do not always migrate, though these resident eagles may travel significant distances in winter to seek food. Ruffed grouse stay with us, growing fringes on their toes in the winter to act like natural snowshoes and spending cold nights using the snow as insulation – imagine using the snow to stay warm. Next we can look at the resident bird that carries a bit of Christmas red color, the pileated woodpecker. These birds make deep, oval excavations in trees to find ants, especially carpenter ants, and wood-boring beetle larvae. These woodpeckers apparently have the “spirit of giving” year-round, as their large excavations often become feeding stations for other woodpeckers, wrens, or other birds.
Frogs have an interesting Christmas. Wood frogs, for example have no heartbeat. They do not breathe. Their blood does not circulate. Their nerves barely register electrical impulses. They are essentially frozen solid, yet their vital organs are not damaged. Spring peepers, gray tree frogs and upland chorus frogs also may freeze and thaw several times during the course of a winter. How do they do it? The answer is antifreeze. When ice begins to form on a wood frog’s skin, the frog’s liver releases a high level of blood sugar, enough to fill the blood vessels in all vital organs, creating a type of antifreeze. Other frogs will burrow into the soil or a lake bed to keep from freezing. Leopard frogs sink to the bottom of a water body, where they sometimes unfortunately become food for a fish.
Where do turtles go in the winter? All but one of Wisconsin's eleven turtle species spend Christmas under water. A few turtles bury themselves while others remain motionless on the bottom. Some scientists believe that they hibernate, their blood changing to function like antifreeze, with their body temperature dropping to only a few degrees above freezing. Other scientists believe that they don’t hibernate, but are semi-active, although this activity can take a toll on their body reserves.
When do black bears go into hibernation? Do they nestle in their beds for a long winter’s sleep? Technically, bears go into torpor, which is a state of reduced metabolism from which they can be awakened. Male black bears don’t always go into dens, sleeping right on the ground, or under downed treetops. These males can be more easily aroused from their “winter’s sleep.” When you add the fact that there are a lot of humans moving around in the forest during our fall hunting season, and combine it with the current feeding and baiting of deer or other animals, it is possible to see signs of bears even through November. The latest I have seen bear tracks in the snow is December 13, although most female black bears can go into torpor as early as October first.
As I wrap my presents, enjoy my lit tree, and huddle inside my warm house, waiting for a holiday season, I again find a renewed sense of wonder at the natural world. How fortunate we are to be able to enjoy this variety of wildlife all year round, no matter what the season or conditions in which we find ourselves.
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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