Following a week of sub-freezing temperatures, Kingsford Lake is now completely iced over from shore to shore. The lake is shallow, actually mostly man-made in that it started out life a hundred years ago as a small lake on a river. The river was dammed and the shallow river basin and surrounding floodplain flooded to form the lake. Most of the lake is ten feet deep at most, with just the original small lake being very deep. Because the lake is so shallow, it freezes quickly, and even the small current that still exists along the river’s original bed, which stayed open till the last, is now solidly closed up.
We haven’t been able to cross to the other side of the lake for about a month, since ice started to form on the water and we pulled the boat up onto shore. Today, we took Raven and headed out across the ice to wander about the lake. We headed first to the island that’s in the centre of my blog header, on the east side of the lake. Dan wanted to look for owls there, but with so much habitat available to them we didn’t find any while we were out. From there we crossed back over the open expanse of the lake to the west shore, our second destination the large marshes that fill in the shallow western bays.
While the water was open we weren’t able to go in here; the water was sufficiently shallow, and the lily pads and pond weeds sufficiently dense, as to prevent any sort of meaningful boat traffic through the area. It might be possible in the spring and early summer for me to bring my canoe over, which would be a little more maneuverable than the punt boat, the water level should be higher then, and the plant life won’t have begun to fill in yet.
Now that the water has frozen over, however, we can easily walk among the cattails. Dan commented that he thought it might be the first time he’s actually walked through a marsh. It was a reasonably large wetland, especially for our area where wetlands are sparsely scattered and tend to be small.
The history of the lake is apparent in these shallow areas. There are many aged, weathered stumps, and tangled root masses from dead trees that had toppled over in the softened soil. When the river was dammed this area would have been forest, and much like with beaver ponds, the result of the newly-formed lake was a lot of dead trees. It amazes me that so many of these stumps still persist, given their presumed age.
Some of the root tangles make fabulous natural sculptures. You can see why they really appeal to some people as art pieces (check out these amazing driftwood horses by artist Heather Jansch I found while looking for a driftwood sculptures link; I would love one of these, but where would I put it?).
The cattails in the marsh here appear to be Narrowleaf Cattail, Typha angustifolia, separate from the Common Cattail (or Broadleaf Cattail), T. latifolia. I can’t remember consciously noting unusually narrow cattails before, though I would be surprised if I hadn’t encountered the species prior to now. In the Toronto area I only really recall encountering the latter, certainly the most common cattail species there. Here, everything seemed to be the former species, so far as I could tell from their dead, broken stalks. There were also a few reeds and sedges mixed in with them, but fortunately no sign of the invasive phragmites.
We poked around looking for nests. Nests are definitely easiest to find in the winter, when they become exposed as the vegetation that concealed them in the summer dies back. Many don’t make it through the fall and winter weather, but some that are particularly well-constructed or protected may survive without too much damage. Searching for nests in the marsh is definitely easiest at this time of year, as you can just walk through the dead vegetation looking for dense clumps.
We found five in the area we covered; not as many as I expected considering that Red-winged Blackbirds will probably be dime-a-dozen there come spring, and then you’ll also have other marsh nesters in there as well, but a good collection nonetheless. Most of them looked like this as you approached – a dark mass topped with a distinct white crown of snow. It was hard to tell what you’d found until you approached and brushed the snow off the top to assess the size and shape of the nest. The size of this one, along with the coarseness of the materials used in its construction, leads me to believe it’s one of the many Red-winged Blackbird nests that were probably built there last summer.
Here’s another Red-wing nest. I’ve found, at least in the nests I’ve observed, that they tend to use broader grasses and other materials when they’re building the outside of the nest, giving theirs a distinctly coarse appearance that you don’t really see in other cup-shaped nests of marsh species. I’m always amazed when I look closely at these just how well they’re woven around the supporting vegetation – so snug, you can’t remove it without a pair of scissors to snip off the vertical stalks. A human would require some skill to produce something like this, and a human has opposable thumbs!
This one is a Marsh Wren’s nest. We haven’t observed any Marsh Wrens here since we moved in; they’re most easily detected by their distinctive, chattery mechanical song. By the time of our arrival in August they would have all stopped singing. But here is clear evidence of their presence last summer. Marsh Wrens build domed nests, completely enclosed except for a small wren-sized entrance hole near the top on one side. The interior is deep; if you stick your fingers in one (as I’ve done a few times when checking the contents of an active nest), your fingers will just barely reach the bottom to be able to count the eggs. Not too many species build enclosed nests like this, and as far as marsh nesters go their nest style is unique.
Finally, another cup nest, woven into the cattails and suspended above the water in the manner of the Red-wings. It differed from the blackbird nests, however, in the coarseness of the grass used to construct the outer walls. It’s got a tidier, finer appearance to it, subtle enough that it could possibly just be a fastidious blackbird, but I think it may actually be the nest of a Swamp Sparrow or Common Yellowthroat. I’m leaning toward the latter, based on the wider vegetation woven into it. It resembles this yellowthroat nest to me more than it does this Swamp Sparrow nest.
Whatever it was, the youngsters fledged successfully. How can I tell this? If you look closely, you’ll see some droppings on the rim of the nest. The nest was actually tipped down toward that side, I righted it a bit for the purposes of a good photo. Nestlings, as they’re preparing to take that great leap of faith that will turn them into fledglings, will perch on the rim of the nest. Their weight as they all do this will often cause that lip of the nest to fold down, or sometimes for the whole nest to tip. Also, just before they leave they’ll often poop, a reflexive habit birds have that may perhaps be to “lighten their load” for flight. The presence of droppings on the lowered rim suggests that the youngsters at least made it as far as that stage of life. Hopefully they’ll make it through the winter and we’ll get to see them return come spring.