Muskrats were featured in mid-November, and a brief mention was made of push-ups and feeding huts. From now until ice-out, these features will be prominent in local marshes, as Muskrats continue to ramble beneath the ice and snow.
Muskrats out on the ice are pretty exposed, so they create pushups . To form a pushup, Muskrats chew a small (10 – 15 cm) hole in the thin, newly-forming ice, and “push up” a pile of vegetation less than a half-metre high. This wet vegetation freezes, and forms a hard little dome for the muskrat to breathe and rest in safe from predators. In Alaska, Blackfish will also use the holes to get oxygen, and their activity helps the Muskrat maintain an open hole. Yes, everything is connected.
To confuse matters a bit, Muskrats also build feeding huts in the winter, which are mid-way in size between a lodge and a pushup, and are used more for feeding than the pushup is, since there is more room. Unlike most lodges, both push-ups and feeding huts will collapse in the spring.
With this network in place Muskrats can stay busy all winter, following their trails under ice and chowing down on cattails.
INVASIVE ALERT!– Phragmites
Cattails, are the muskrat’s favourite food and an abundant plant that thrives in Canadian freshwater wetlands. However, even the tough cattail is under threat from an invasive grass species that is an ecological bully! European Phragmites was identified by Agriculture and Agri-Food Canada in 2005 as Canada’s worst invasive plant! It aggressively crowds out native plants and releases toxins from its roots which affect the growth of other flora. You might think that a grass species like Phragmites must provide great cover and food for wildlife. Unfortunately, Phragmites stands are so dense that they provide very poor habitat and the plant has almost no nutritional value. Sometimes this species grows so thickly that it actually reduces water levels in the marsh which impacts wetland wildlife like fish and amphibians. One of the more interesting aspects of the Phragmites invasion is that there is an American subspecies which is native to North America and poses no threat. However, the tall European Phragmites plumes are hard to miss, especially in the winter when you might be out looking for wildlife signs like muskrat lodges. So enjoy a midwinter wetland trip and if you encounter Phragmites report your sighting to an invasive species hotline to help keep our wetlands safe from this hostile intruder!
So far, very few Great Gray Owl sightings have been reported in southeastern Canada but this beautiful boreal forest resident sometimes wanders south in winter seeking food. Keep an eye out for them. Snowy Owls are also regular winter visitors to southern regions of Ontario, Quebec and the western Prairies. While this does not appear to be an irruption year, they will no doubt be recorded in Christmas Bird Counts across Canada. Snowy Owls are also regular visitors to some U.S. states, where they are being tracked through Project Snowstorm . So with lots of winter remaining, keep your eyes open for migrant owls and other remarkable birds of prey like Golden and Bald Eagles as they cruise over frozen landscapes in search of a tasty meal!
Black-capped Chickadees, Red-breasted Nuthatches, and White-breasted Nuthatches are active throughout the winter. Chickadees survive in part by significantly lowering their body temperature at night, and choosing good roost holes. They also stay dry with oil from their preen gland. Still, in very cold weather they may need to eat their weight (40 g) in food each day to survive. They eat lots of conifer and other seeds as well as insects that they find and have cached away. Chickadees will also snack on fat and bits of meat from dead animals opened up by larger predators and scavengers. Nuthatches will huddle together in hollows or nesting boxes. Look for survival signs of birds that stick it out through the winter. Observing Goldenrod galls (which we discussed in mid-September) may provide just such survival signs. Goldenrod galls are very evident now, as much of the vegetation has died back. The Goldenrod Gall Fly makes its home in the gall for the winter, but eats a tunnel close to the surface before it goes dormant. You may find galls opened and the larva eaten by either Downy Woodpeckers or Black-capped Chickadees, adding to the food web that these insects support. Keep checking on these galls throughout the winter to see how many become a bird lunch. You might also see European Starlings, Mourning Doves, and Canada Geese out and about at this time of year.
Beavers are mating - faithfully. They mate for life until one dies. Find active lodges by checking after a recent snow for a dark patch, depression or gap around the breathing hole near the top, where the animals’ heat has melted the snow.
Early this month Black Bears give birth to two or three cubs, about the size of chipmunks and very cute - Rick Mercer certainly thought so!
In early December we talked about the molecular magic of snow, and with recent snow squalls and cold temperatures winter has certainly arrived (scroll down). Have you ever wondered if relatives or friends are enjoying (or maybe I should say experiencing) snow elsewhere in the world? Check out this website to see current snow and ice cover around the world.
As our orbit around the sun gives us seasons, we also get a different view of the stars. On top of that, the Earth’s spin provides slightly different views, as the locations of constellations appear to move over the course of a night sky. The best known constellation is the Big Dipper (Ursa Major), which is visible to us in the Northern Hemisphere year round since it is located above the horizon. The Big Dipper is low to the northeast now. Due to the Earth’s spin it will appear to rotate around the North Star (Polaris), which can be located by extending out (or up) from the two stars at the end on the big dipper’s bowl. There a lots of good reasons to star gaze. It can also be integrated with subjects such as history. Stellarium is a great, free teaching tool for bringing the night sky into the classroom. Nothing beats star gazing on a dark, clear winter night with hot chocolate though (here are some activity ideas)!
Another meteor shower, the Quadrantid, occurs before dawn on January 3rd and 4th. The peak is very narrow, and ill-timed this year for North America, so you may only see a few.
The moon approaches the star Aldebaran on the 9th. Aldebaran was once the pole star, almost a half million years ago. Find out why. Sirius, the Dog Star, will become the southern pole star in about 7000 years.
Venus is furthest from the sun on the 12th, with Mars just above and to the left. Mercury peeps up above the horizon before dawn on the 17th, with Saturn just above it. The moon falls by Jupiter a night later.