The cool weather and gray skies arrived this past week, and with them came the fall birding doldrums. This usually hits me when I realize that we are now halfway through the fall migration season, and that more species have already departed than are still left to come. It’s going to be at least seven months before I hear another Ovenbird or see a flock of Barn Swallows swooping over farm fields; the Wood Thrush, the Eastern Kingbird, and the Yellow Warbler are all somewhere far south of here. Both the birds and the seasons are moving on, and this was made evident when we had to turn the heat on as the nights started dropping down into the single digit temperatures.
I headed out to the Eagleson Ponds yesterday morning, but didn’t spend much time there as there wasn’t much to photograph. After about an hour I ended up with 27 species, and for the first time in months I did not see or hear the Northern Flicker. Sparrows and finches were abundant – it was a mild morning, and several Song Sparrows were still singing. A couple of White-throated Sparrows were attempting to sing, too. A couple of those popped into view when I started pishing, as did an adult and juvenile White-crowned Sparrow.
One of the most common atmospheric displays is the 22° circular halo, such as this one that I photographed in Kanata on Saturday. Created by sunlight refracting through hexagonal ice crystals suspended in the atmosphere, they are visible throughout the year and are easiest to spot when the sky is covered with a thin layer of high altitude cirrus clouds. The halo is always a distance of 22° from the sun, or about the distance between your thumb and pinkie finger when your arm is fully extended with all your fingers spread. Although the hexagonal ice crystals may be randomly-oriented, the diameters of the crystals are less than 20.5 micrometers.
This isn’t the first time I’ve seen a mouse in our house; unfortunately, the last one was discovered by my cats sometime in the night, and I found its dismembered remains in the kitchen the next day. Actually, one of my cats found this one too, but it was still alive when I noticed him playing with it. I was working on the computer when I heard my male, Jango, playing with something in the doorway. I wasn’t sure what he was doing, and when I looked over, I saw a small brown rodent streak across the hall toward the guest room. Jango followed it, and so did I. I shooed the cat away and then went to get a glass to catch the mouse. By the time I returned, the mouse had vanished. Doran has a live-catch mousetrap, so we set it in the guest room with some peanut butter in it. When we checked the trap the next morning, the mouse was in it.
However, three woodpecker species exist which have only three toes. Two (the Black-backed Woodpecker and the American Three-toed Woodpecker) are found in North America, while the third (the Eurasian Three-toed Woodpecker) is found in the Boreal regions of Europe and Asia. These species all inhabit coniferous forests where they feed chiefly on wood-boring beetle larvae. The American Three-toed Woodpecker has the northern-most breeding range in North America, while the Eurasian Three-toed Woodpecker has the northern-most breeding range in Eurasia. These two species were considered one species until 2003, when they were split because of differences in voice and in mitochondrial DNA sequences. All are believed to have a common ancestor which lost the first toe, the hallux, over time.
The fourth toe is not fixed in a backwards direction, but is able to rotate sideways or even forwards as the woodpecker moves up and down a tree. It is thought that woodpeckers with four toes only use three toes to grip the tree trunk, while the fourth is kept beneath the leg or extends out to the side, thus limiting the amount of force a woodpecker is able to deliver while hammering on a tree trunk. Woodpeckers with three toes do not need to accommodate this extra toe and are able to extend their body back further from the tree when it strikes.
We haven’t received many heavy snowstorms since the new year, but the few that have occurred on the weekend have started early in the day. Twice I went out birding first thing in the morning and only managed to spend an hour outdoors before a curtain of snow descended. Ottawa actually hasn’t received a lot of snow this winter, but since we haven’t had any significant thaws either, the snow cover is fairly deep.