House Finch

House Finch - Carpodacus mexicanus

House Finches winter in Calgary and are less common during the spring and summer. Purple Finches are usually not present during the winter and return in the spring. 

The two species can be difficult to differentiate. The finch below was near the top of a tall spruce tree and without my binoculars I was not able to identify the bird. Fortunately I had my camera and the identification was straightforward once I viewed the image on my computer.



The finch on the spruce branch above is a House Finch,

The red colouration in a House Finch is brightest on the forehead and over the cheeks (malar area). In a Purple Finch the entire head is red. 

The upper beak in a House Finch is curved. In a Purple Finch the beak is straighter. 

The tail in a House Finch is longer than the tail in a Purple Finch. In flight, the tail notch in a Purple Finch is more distinct. 

References
Sibley DA. The Sibley Guide to Birds. Alfred Knopf, New York. 2000.

Tracking Beaver

Canadian Beaver - Castor canadensis

The Canadian Beaver is the second largest rodent in the world.

Good beaver tracks are uncommon because the prints are usually wiped out by either the heavy flat tail or by the tree trunks and branches that the animal drags to the water.

The beaver has five toes on the front and hind feet but only three or four usually register. 

The impressions of the large broad nails are visible in the left hind print in the photo below.

The quarter-inch incisors of a beaver can cut down a five-inch willow in three minutes! Beavers strip the bark to access the nutritious inner cambium layer.

The protective wire placed around this aspen was not much of a deterrent for a hungry beaver.
  

The photo below shows the stumps of numerous aspen cut down last year and dragged into the water for use during construction of a lodge.

Once a beaver starts to cut down trees in a grove, these natural engineers tow the trunks and branches to the water over the same trail. This technique clears the pathway and forms channels with progressively lower resistance to drag, and makes the process faster and more energy efficient. The photo below shows a drag channel over the shore and a typical notch at the edge of the water.

References
Naughton D. The Natural History of Canadian Mammals. UofT Press. 2012.
Rezendes P. Tracking and the Art of Seeing. How to Read Animal Tracks and Signs. Firefly Books Ltd. Willowdale, Ontario. 1999.

Tracking Meadow Voles # 2

When the snow disappeared from the garden in my front yard, the bark at the bottom of my columnar crab apple tree was chewed off. 

The crab tree is located in designated garden area that is only a few meters from the driveway of my neighbour. You can see the pebbled pavement in the lower left of the photo above. My neighbour shovels his driveway and he throws the snow up on my lawn. Over this last winter, the snow was piled up about four to five feet high in this area. Moles choose to nest under deeper piles of snow. The grass above is filled with typical Meadow Vole runways through the grass and burrows.

A close up of the gnawed area shows tiny grooves that fit with the size of Meadow Vole incisors. Tiny chips of orange bark are strewn on the ground at the base. The vole chewed through the bark to reach the nutritious rich inner cambium layer. This layer of undifferentiated cells produces the bark.

Meadow Vole scat was piled around the base of the tree. There is enough scat in the photo above to confirm that the tree offered many meals for the animal.

There was another pile of scat on the other side of the tree. This scat has a slightly darker and different colour. Perhaps this poop was from a second vole with a slightly different diet. Another possibility is that the scat was formed by the same vole but during a time when the diet of this vole was otherwise different? Or perhaps this vole ate and digested more of the outer bark? 

Prairie Crocus

Prairie Crocus - Anemone patens

The Prairie Crocus is one of the earliest spring flowers. The flowers are prominent on southern exposed slopes. When the snow melt is delayed, the flowers can spring up through thin layers of snow or they appear within days after the snow disappears.

The ants in the photo above are likely attracted to calorie-rich nectar produced by specialised glands (nectaries). Ants are not efficient cross-pollinators. A protective chemical (antibiotic) produced by ants can inactivate pollen. 

The silky white hairs that envelope the stems and the leaves are visible under the lowermost flower in the photo above.

Anemone is from the Greek "anemos," which means the wind. These flowers propagate well in windy habitat. The fruit of the flower (achenes) develop attached to a long feathery tail, that helps with wind dispersal.

References
Cotter GW & Flygare H. Wildflowers of the Canadian Rockies. Hurtig Publishers. Edmonton. 1986. 
Phillips HW. Northern Rocky Mountain Wildflowers. Falcon Publishing. USA. 2001.

Thirteen-lined Ground Squirrel - Spermophilus tridecemlineatus

The cheek pouches of this Thirteen-lined Ground Squirrel are filled with the husked sunflower seeds I put out for the birds who prefer feeding on the ground. The seeds regularly attract red and black squirrels, chipmunks, and meadow voles. For several years, a Thirteen-lined Ground Squirrel has been a regular visitor. The squirrel turned up on April 2nd this year. The same day I found a hole at the base of the fence between my property and the meadow behind my home. I suspect the three inch diameter hole is the entrance to a burrow and winter nest for the squirrel. These squirrels emerge from winter hibernation in April, so the timing fits.

Thirteen-lined Ground Squirrels are solitary apart from during breeding season in early spring. In Canada the squirrels emerge from hibernation in spring and they disappear back to the nest in late summer. A home range is usually about two or three acres.

The sunflower seeds this squirrel scavenges over the spring and summer will help sustain the animal over the winter. 

References
1. Naughton, Donna. The Natural History of Canadian Mammals. University of Toronto Press. 2012.

Translucent Yellow Gelatinous Organic Mass in Elbow River

Last November I photographed this translucent yellow gelatinous organic mass on the floor of a shallow portion of the Elbow River. I walk by this location several times a week and the mass seemed to suddenly appear. The mass was several feet high.

Several days later the mass had deflated and was lying on the floor of the river. This implies the interior of the mass was filled with a gas.

The growth was located in a section of the Elbow River that is shallow and located between the mainland and a gravel bar about about 8 to 10 meters offshore. Until the flood in June 2013, the gravel bar was an island with a beaver lodge. The flood deposited enough dirt and gravel to connect the west end of the island to the mainland. This created a shallow blind inlet at the eastern end of the island. Since the river flows from west to east, the water movement in this newly created inlet is slow. The growth was close to the sun exposed southern shore of the river. Since the river is shallow, the temperature of the water in this location is higher. Slow water movement and a higher temperature likely favoured the growth of this organic mass.

By mid-March the snow had melted on this portion of the Elbow. Over the intervening four winter months the mass totally disappeared.

I spent research time on the Internet but was not able to identify the cause of the growth. Since the Elbow River provides the water supply for Calgary, I wondered about the toxic potential for this unusual growth. I sent the above photos to a provincial water expert to request assistance to identify the organic growth. I received a reply but no answers.

I will monitor the location this year to see if the mass redevelops.