Seasonal waterfront homes

Marsh in winter

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.

Marsh in winter

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.

Marsh in winter

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.

Driftwood

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?).

Narrow-leaved Cattail

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.

Red-winged Blackbird nest

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.

Red-winged Blackbird nest

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!

Marsh Wren nest

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.

Nest - Common Yellowthroat?

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.

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Cotton candy for blackbirds

Edit: This post was recently included in the 182nd edition of the Friday Ark, a blog carnival focusing on animals of all sorts.

Cattail head

I’m sure we’ve all seen these in our local wetlands, cattail heads that have become all poofed out as winter progresses, like so much cotton-candy on sticks. I’d never given it much thought before, and if I had I suppose I’ve just assumed that the fluff has something to do with the cattail releasing its seeds to the wind, much like milkweed does.

A few weeks ago, my mom bought the book Insects: Their Natural History and Diversity (with a photographic guide to insects of eastern North America) by Stephen A. Marshall. Steve Marshall is a prof at the University of Guelph, where I did my undergrad, and was one of the instructors leading the Ecuador field course that I took. I didn’t spend much time with him (I knew the other prof better), but he was a really nice guy. So I thought it was cool that Mom had got this book, and I sat down to leaf through it. I was primarily interested in the 40-someodd pages of moth plates, and while flipping through those I spotted an image of fluffy cattail heads. Intrigued, I read the plate caption associated with the figure.

Turns out, those fluffy cattail heads you see in the middle of winter aren’t just the cattail doing its thing. Sure, it will naturally begin to loosen the fluff and lose some to the wind. But the cotton-candy formations? They’re the work of a tiny, drab little moth called the Shy Cosmet (Limnaecia phragmitella). Its caterpillars are appropriately known as Cattail Caterpillars. They feed on the seeds of the cattail in the fall and spring, overwintering inside the head as a larva. In late spring they pupate and emerge as an adult moth in early summer.

Cattail head

In order to ensure that they have a secure home for the entire duration of their stay, they spin tiny silken threads that act as a web holding all the fluff inside. The cattail will still loosen its seeds from the stalk to try to spread them on the wind, but the caterpillar’s netting holds them in place. The result is a rather lumpy cotton-candy appearance.

I thought this was all pretty cool, so I did a bit of searching on the web and discovered a post about the Shy Cosmet, made recently, by Gerry Wykes at Naturespeak (he calls Detroit home, so is within my rather broad neck of the woods). In it he brought in a cattail head and gently dissected it to expose the caterpillars hiding within. Now, I suppose I could have just taken him at his word, but I really wanted to go out and have a look for myself. Insatiable curiosity. In the name of science, of course. I brought in two heads for good measure, and opened them up in a tub to contain any wandering worms.

Cattail fluff

Gerry indicated that it would take a moment or two for the caterpillars to poke their heads out of the fluff, that they wouldn’t be immediately visible. So I sat there and patiently waited. And waited. Nothing happened. No heads, no tails even, not a hint of movement. I’ll admit that they should all be dormant at this time of year, but since he’d had such luck with his coming out as soon as they were warm, I was beginning to wonder if I’d picked a dud cattail head, one that really was simply just loosening up its fluff.

Cattail seeds with caterpillar frass

So I started gently teasing apart the clumps. I found lots of what looked to be frass in with all the seed heads. The seeds are tiny, flat and boxy at the end, and brownish in colour. The frass, on the other hand, was gray and round, spherical. There was lots of it, but no caterpillars associated with any of it.

Finally, after standing with my head bent over this dish for many minutes, I discovered one. Only one, just a single, lone, under-developed caterpillar. Perhaps the cattail head had already been picked over by foraging birds and this was the only guy to have survived. Perhaps there never were many to begin with, maybe I missed one or two. But I went through the entire two cattail heads and only found one. By the time I was done, they looked like this:

Cattail fluff

Cattail Caterpillar

Here’s the caterpillar. I found him tucked in a clump of relatively undisturbed fluff, nearly comatose. He wiggled a bit when I first picked him out, but didn’t go anywhere. Gerry was describing his caterpillars crawling all over the place, making getting a good photo difficult. Mine was very photogenic.

Cattail Caterpillar

This is the caterpillar posed with my mom’s finger for scale. He was tiny. Tiny tiny. This is why I wouldn’t be surprised if I missed a couple others, although I was paying close attention. Below is the caterpillar beside a measuring tape. You’re looking at the inches side of the tape. Each one of those black dashes is 1/16″. See? Tiny tiny, it’s not that my mom has big fingers…

Cattail Caterpillar

Cattail Caterpillar

I actually found the dried husk of an older caterpillar in the fluff as I was starting to clean up. This gives you an idea of what it should grow to before pupating. He’s got a ways to go.

These little caterpillars form one of the primary food sources for Red-winged Blackbirds upon their arrival here in the spring. It seems like they’d need to eat a lot of them to get much nutrition, but evidently it works for them. A couple springs ago I got a photo of a female Red-wing poking at cattail heads. I thought at the time she was looking for nesting material, but having learned this, it seems apparent that she was actually searching for caterpillars. Who knew? Cotton candy indeed.

As for the book, I highly recommend it. It’s got great photos for an identification reference, and excellent information to complement them. The notable entomologist E.O. Wilson is quoted on the cover: “I wish I’d had Stephen Marshall’s book when I started out in entomology. Its countless photographs and notes bring alive the vast diversity of the insect world.” That’s like Roger Tory Peterson endorsing a bird reference book. There’s so much cool stuff in the book, lots to look at. The only downside: it weighs a tonne. Probably almost literally. At 730 pages and nearly two inches thick, a field guide it’s not. Still, it has the best collection of printed moth photos I’ve seen, plus so much other stuff, I ended up getting a copy myself (should be in the mail). It retails in store for $95, though generally cheaper online, but I found a copy on eBay for $33 plus shipping, so if you look around you should be able to get a good deal on it. Amazon has it on sale for $60. It’s also got a couple images of inside the book so you can take a peek before you buy.