An online resource based on the award-winning nature guide

January

Two For One

2-15-19 cardinals _U1A8442Thanks to warmer temperatures and a vast increase in the number of bird feeders, Northern Cardinals have expanded their range northward as far as Canada over the past century. Males get far more attention than females, due to their year-round brilliant red plumage. However, the female Cardinal is equally striking with her more subtle tan plumage highlighted with touches of red. Believe it or not, it is possible, albeit very rare, to find both of these plumages on one bird.

Recently an interesting phenomenon known as a bilateral gynandromorph was recorded in Pennsylvania — a cardinal whose body is half male, half female. (For a detailed explanation and video, go to https://www.nationalgeographic.com/animals/2019/01/half-male-half-female-cardinal-pennsylvania/?fbclid=IwAR2KbCmxuGxtGmKug2eLPS9JD6Vf_KV93OWgy0UsKuMAO-p_2soISJgM400.) Not just the plumage, but the anatomy of this bird is half male, half female. The way in which this gender division exists has a unique effect. According to National Geographic, “Most gynandromorph individuals are infertile, but this one may actually be fertile as the left side is female, and only the left ovary in birds in functional.”

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Otter Holes

1-30-19 otter hole img_5596A pond can have one to two feet of ice on top of it, yet North American River Otters somehow manage to find a way to come up through the ice. How do they do this? Careful observation reveals that the ice where otter holes are found is thinner than most of the pond’s ice. Otters rely on spring-fed open water and areas of thin ice for surfacing holes. Here they break through the ice and often drag larger fish out onto the ice to eat them.

If otters are feeding in a beaver pond and they can’t find openings in the ice for fishing, they have been known to tunnel into beaver dams for access to open water. In late winter, water levels sometime drop below the ice, leaving an air space that lets otters swim and hunt beneath the ice without the need for holes. (Look closely at opening to see the actual hole beneath the surface water that they emerge from.)

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The Sniff Test

1-30-19 red fox marking img_7153When your quest is to find out as much as you can about the identity, activity, diet and territory of your four-footed neighbors, it is logical to make the most of all your senses. Tracks can be seen, scrapings and bite marks on a tree can be felt and yes, one’s sense of smell can enhance any tracking expedition. Just as the tracks and scat of different species of animals have distinctive characteristics, so does the urine of different animals. Scent marking, including urination, is a behaviour used by animals to identify their territory, and therefore a highly visible sign in winter.

At this time of year, foxes are breeding, and without even putting your nose near where a fox has marked his territory with urine, you can detect its skunk-like odor as you pass by. If you’re so inclined (and I realize many readers may not be) you can heighten your sensory experience as well as your identification prowess by sampling the smell of other animals’ liquid waste. White-tailed deer urine has a pungent, piney smell, quite pleasing to this naturalist’s olfactory receptors. You can detect a porcupine den from a considerable distance by the pungent, very distinctive but hard to describe odor of its urine (which spills out onto and coats the bark of a tree den, thereby advertising the porcupine’s presence). Coyote urine smells very much like a domestic dog’s, and members of the weasel family often have musky-smelling urine, though a recently-sniffed fisher marking had very little scent.

Needless to say, it’s a lot easier to discover and sample urine when there’s snow on the ground and it is more evident. Virginia opossums, snowshoe hares, red and gray squirrels, eastern coyotes, red and gray foxes, raccoons, fishers, mink and striped skunks are all in or entering their breeding seasons, when scent marking is more frequent. Snow is currently on the ground, at least in northern New England. It’s prime time for olfactory activity, if you’re game. (Photo: stump marked by a red fox)

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Common Gartersnakes Brumating

1-28-19 gartersnake img_4888Somewhere between two and four feet (depending on where you live in New England) beneath our feet there is a “frost line” below which the ground water in soil doesn’t freeze. Snakes, being reptiles, are ectotherms, and their bodies assume the temperature of the air around them. In order to avoid being frozen to death in the winter, they retreat below the frost line, where they enter a state called brumation – the cold-blooded term for a state of torpor and inactivity that is not true hibernation, but in which a dramatic slowing down of bodily functions occurs. Crevices in south-facing rocky ledges and abandoned woodchuck, fox and skunk dens (and human cellars) often serve as hibernacula, or winter shelters. Common Gartersnakes are known to gather in large numbers (one Canadian den served as a hibernaculum for 8,000 gartersnakes), in order to concentrate the small amount of heat their bodies produce in the winter.

As the air temperature lowers in the fall, a snake’s body temperature falls and its metabolism decreases dramatically. Gartersnakes actively prepare for this by not eating for several weeks prior to hibernating. This allows all of the food they previously consumed to be completely broken down and absorbed into their system. To enhance this process, gartersnakes bask in the sun both before and during their early days of sheltering in hibernacula, warming themselves so as to increase the rate of their metabolism just prior to hibernating.

Should a snake happen to eat a large grasshopper, earthworm or small frog just prior to entering brumation, the snake may become extremely lethargic due to the slowing down of its metabolism, and the contents of its stomach may not be digested as quickly. The longer it takes to process food in its stomach, the greater the chances that this dead material will start to decay, which could result in serious illness to the snake.

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Some Cedar Waxwings Have Orange Tail Tips

1-23-19 cedar waxwing with orange tail tip_u1a2642Cedar Waxwings can be found in most of New England year-round. They are one of the few North American birds that specializes in eating fruit, particularly in the fall and winter. Unlike the Pine Grosbeak (see 1/16/19 post), which crushes the fruit and consumes only the seeds, Cedar Waxwings eat the whole fruit. If it has fermented, they will feel the effects and, like humans, become somewhat tipsy.

If you look carefully at a flock of Cedar Waxwings you may spot one that has an orange-tipped tail, rather than yellow. This has to do with the bird’s diet. Morrow’s Honeysuckle (Lonicera morrowii) was imported in the late 1800s for use as an ornamental, for wildlife food and cover as well as for soil erosion control, but it is now recognized as an invasive plant. Its fruit contains red pigment in addition to the normal yellow pigment found in honeysuckle berries. If a Cedar Waxwing happens to eat enough of the fruit of Morrow’s Honeysuckle at the time of feather formation (they molt between August and January), its tail feathers will have orange tips instead of the usual yellow. Cedar Waxwings with orange tail tips began appearing in northeastern U.S. and southeastern Canada in the 1960’s.

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Coyotes Investigating Beaver Lodges

1-21-19 beaver lodge img_6186Over the past century beaver trapping has declined and beavers have returned to many of their former habitats. Wolves also have come back in a few areas (not the Northeast yet) — but most places where beavers now live remain free of wolves. As a result, the beaver population has continued to increase, limited only by a few predators, primarily humans and Eastern Coyotes.

Coyotes are major beaver predators and have established themselves throughout the Northeast partly because of the abundance of prey and partly because of the absence of wolves, who keep coyotes out of their habitat. During most of the year, coyotes can take advantage of beavers that leave their pond to feed on land. When they are in their lodges, however, beavers are fairly safe from coyote predation, especially if their lodge is surrounded by water. Come winter, when ponds freeze and beavers remain in their lodges, coyotes can easily approach an inhabited lodge by walking over the ice. Thanks to the lodge’s two to three-foot-thick walls of frozen mud and sticks, the beavers within are safe. (Photo: signs showing a coyote’s attempt to access a beaver lodge)

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Leaf Marcescence

1-14-19 beech leaf _u1a9125Deciduous trees typically lose all of their leaves by late autumn. However, when snowshoeing or skiing through the woods this time of year, one is likely to find a scattering of deciduous trees that still have leaves clinging tightly to their branches. These plants are exhibiting marcescence, the trait of retaining plant parts after they are dead and dry.

Most deciduous trees form a layer of cells called the abscission layer at the base of each leaf’s stem, or petiole, where it attaches to the branch. This layer is composed of thin-walled cells that break easily, allowing the leaf to drop. A thin layer of corky cells seals the tree at the spot where the leaf was attached. Abcission layers are not formed on marcescent trees such as oaks and the American Beech, all members of the family Fagaceae. Therefore, their leaves do not fall off as readily, and many remain attached through the winter.

The evolutionary reasons for marcescence are not clear, though theories include defense against herbivory (e.g. browsing by deer), protection of leaf buds from winter desiccation, and as a delayed source of nutrients or moisture-conserving mulch when the leaves finally fall and decompose in the spring.

Leaf marcescence is most often seen on juvenile trees, and on the lower branches of older trees.

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