American Black Ducks Vs. Mallards
American Black Ducks (Anas rubripes), found year-round in all parts of New England except for northern Maine, are nearly identical to Mallards (Anas platyrhynchos) in size, shape and voice. Both have rounded heads, thick bills, and bulky bodies. Like other dabbling ducks they sit high in the water with their tails high. These two closely related species often keep company with each other and it can be challenging to tell them apart, but it is possible to distinguish them with some certainty.
Most of the year male (drake) Mallards have a distinctive iridescent green head, a white neck ring and a yellow bill. However, the female (hen) Mallard’s plumage is very similar to that of both drake and hen Black Ducks. One of the most dependable ways to tell these two species apart is to look for the dark chocolate-colored body of the Black Duck, which is noticeably darker than the hen Mallard’s. At rest, the Black Duck is a uniform very dark brown from the bottom of its neck to its tail. The hen Mallard is a much lighter brown in this area, and in addition has a pale whitish patch on the belly. The color of the bill can also help with identification — the hen Mallard’s bill is orange and black, whereas the Black Duck’s bill ranges from a dusky yellow (drake) to a drab olive (hen) color. All of these identification clues go out the window when hybrids of these two species are encountered! (Photo: American Black Duck drake (L) and hen (R) )
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Porcupine Quills
Porcupines possess roughly 30,000 quills — hollow, modified hairs which are made from the same material (keratin) as feathers,claws, scales, hairs and fingernails. They cannot “shoot” their quills anymore than we can shoot our hair, but their subcutaneous muscles can cause the quills to become erect as well as loosen them so that when touched, the quills are easily released. Each quill possesses between 700 and 800 barbs along the four millimeters or so nearest its tip. It is these barbs that help a quill remain embedded in the tissue of a predator.
Researchers have found that barbed quills penetrate deeper into muscle than quills without barbs, and require half the penetration force. They have been found to be four times harder to pull out than barbless quills. It has been suggested that the barbs ease the quill’s penetration by concentrating force along the edges of the barbs, similar to how the serrations on a knife blade make cutting meat easier.
Fortunately for porcupines, their quills are covered with a natural antibiotic which protects a porcupine from infection should it be impaled by one of its own quills or one from another porcupine. (Photo: porcupine with quills from another porcupine embedded in nose)
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Male Woodchucks Out and About
Hibernation, the true slowing down of one’s metabolism (a Woodchuck’s body temperature drops from 99 degrees F. to 40 degrees F. and its heartbeat drops from 100 beats per minute to 4 beats per minute) is one way an animal conserves energy. Male and female Woodchucks use the energy they’ve conserved very differently in early spring.
At the end of February and in March, males arouse themselves about a month prior to the mating season and spend long periods visiting females and defending their territory. Muddy tracks and trails can be seen near their winter burrows (see photo) at this time of year. Females remain in their burrows in a state of hibernation, saving as much energy as possible for the birth and raising of their young. After confirming the presence of females on their territories, males return to their burrows for the next month or so, awakening along with the females in time for their mating season.
The timing of Woodchuck procreation is not a relaxed affair. It is quite precise, in fact, for very good reasons. If Woodchucks mate too early in the spring, their young won’t be able to find food once they are weaned. If they mate too late, their young won’t have the time necessary for putting on weight and storing fat before hibernation begins. Now is the time to look for signs indicating male Woodchuck activity near their winter woodland burrows.
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Red Feather Tips of Waxwings Indicate Age and Status
Both Cedar and Bohemian Waxwings derive their common names from the red, waxy tips of some of their secondary feathers. The color of this wax is due to the presence of the pigment astaxanthin. Ornithologists used to theorize that these red tips protected the feathers from wear and tear, but this has not been borne out in studies.
What has been established is that the red appendages increase in both number and size with a bird’s age. Immature birds usually have 0 – 6 waxy tips. Older birds have more than nine. The number of tips appears to function as a signal of age and status in mate selection; individuals within these two age categories choose each other as mates. It also turns out that pairs of older birds (with high numbers of red tips) tend to nest earlier than younger birds. They also have larger clutches and fledge more young than younger birds with fewer waxy tips.
An easy-to-see cue such as these red feather tips that indicate age, maturity and social status at a glance would be very useful in species such as Cedar and Bohemian Waxwings that are often found in large flocks.
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Virginia Opossums Breeding
If you see a Virginia Opossum in your travels, it could well be on the hunt for a mate at this time of year. It’s even possible you may hear one if you are close enough and the timing is right, as male opossums attract females by making clicking sounds with their mouth.
The breeding practices of this marsupial are unusual, to say the least. The male opossum has a bifurcated (two-pronged) penis (see photo inset), and the female has two vaginas. Not only is their reproductive anatomy somewhat unusual, but the behavior of their sperm is as well. During maturation, sperm pair up inside the male reproductive tract and remain paired after entering the female. Just prior to fertilization the sperm pair separate (into two spermatozoa). This phenomenon occurs only in American marsupials, and not Australian. No definitive explanation exists for this, but perhaps paired sperm increase motility in the female reproductive tract.
(NB: Having an opossum on your land is a real asset – according to biologist Richard Ostfeld, one opossum can kill and eat some 5,000 ticks in a single season. Opossums are said to destroy roughly 90 percent of all the ticks they encounter.)
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Two For One
Thanks 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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Meadow Vole Tracks & Tunnels
Tracking animals can be an elusive endeavor because so many things can alter the condition of the tracks. Have recent flurries erased the details of an imprint? Has the sun melted and enlarged a track? Was every toe registering? Did wind-blown snow cause the tracks to vanish into thin air? Was the animal walking, loping or tunneling or a combination of all three?
The reason you use more than just one track to gather information, such as the stride of the animal and the width of its trail, is that sometimes the individual tracks defy the hard and fast rules of some tracking guides. A commonly accepted generality is that Deer and White-footed Mouse tails leave drag marks, and Meadow Voles’ shorter tails don’t. However, in the right conditions, even a vole’s one-inch tail can drag (see photo), though not creating as long a line as a mouse’s tail would. The Meadow Vole whose tracks are in this photograph was loping along when it suddenly decided to seek cover under the snow and began to (try to) tunnel. Perhaps a predator instigated this behavior.
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Black-capped Chickadees Singing Their Spring Song
Would it surprise you to learn that Black-capped Chickadees have at least 16 different vocalizations? The two most common are its “chick-a-dee” call and its “fee-bee” song. The “chick-a-dee” vocalization for which these birds are named is sung by both sexes throughout the year, but it’s especially common in fall and winter. This call is used to convey a number of different messages. It’s given when a bird is separated from its mate or flock, when chickadees are mobbing a predator (lots of dee notes), to notify others when a predator has left, and when a new food source is discovered.
The two-noted, whistled “fee-bee” vocalization is given mostly by males, although not exclusively. While it can be heard throughout the year, this song is most common in late winter and spring and thus is referred to as the chickadee’s spring song. When chickadees are singing their “fee-bee” song, they are advertising their territories and attempting to attract mates.
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Otter Holes
A 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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Beavers Breeding
Beavers are in the middle of their breeding season, which means copulation takes place under the ice, undetected by human eyes, making information about their reproductive habits hard to come by. What is known about the breeding practices of North America’s largest rodent is that beavers form permanent breeding pairs and are monogamous through consecutive breeding seasons. Should a beaver’s mate die, a new one will take its place. In a colony, only the adult (individuals which are at least three years old) pair breeds. Mating usually takes place in January or February, and typically occurs at night in the water. Gestation is roughly 128 days and three or four kits are born in May or July.
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Wing Prints In The Snow
Rarely have I had the good fortune to come upon a predator dining on its prey, but in this case, luck was with me. Seconds after I spotted a Red-tailed Hawk on the ground working on something it noticed me and flew away, perching within sight so as to keep an eye on its recent kill. This sighting eliminated some of the mystery of the story written in the snow. Wing prints would have revealed that the predator was airborne, and the wingspread might have narrowed the list of potential hawks/owls that it could have been, but determining the species would have been challenging without a sighting.
Although smaller rodents (voles, mice, etc.) make up a greater percentage of a Red-tail’s diet than larger ones, Gray Squirrels (whose remains are visible and were still warm) are consumed. The large numbers of Gray Squirrels on roadsides last fall reflected a booming population which most likely has provided ample food for many predators this winter, including this hawk. Interestingly, fur from the tail had been removed prior to the bird’s directing its attention to the internal organs of the squirrel. A quick retreat by this curious naturalist hopefully allowed the Red-tail to return to its meal.
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Adaptations For Survival
Mimicry, warning coloration and camouflage are three of the many ways in which animals have adapted in order to survive.
Mimicry, when an animal looks or acts like another organism, is illustrated by the Viceroy butterfly which looks remarkably like a Monarch. Warning coloration often makes predators aware of an organism’s toxicity – Red Efts are a prime example. Camouflage, or cryptic coloration, where an animal resembles its surroundings in coloration, form or movement, is exemplified by Eastern Screech-Owls. Not only is their color pattern that of tree bark, but they often stretch upwards and freeze in an upright position, closing their eyes to prevent reflection in their eyes from announcing their presence to predators or prey.
Eastern Screech-Owls come in three color morphs, rufous (https://naturallycuriouswithmaryholland.wordpress.com/2019/01/07/eastern-screech-owls-basking/) gray, and (rarely) brown. (Thanks to Marc Beerman and Howard Muscott for photo op.)
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