December 2008 – Page 2 – Seabrooke Leckie

The birds we counted

I had this written and ready to go yesterday evening, but WordPress suffered a glitch and wouldn’t let me post or save anything. The good guys at behind the scenes got it fixed promptly, however, and hopefully there won’t be any further hiccups!

It had been my original intention to make the post about our CBC as just a single entry, but I found when I got home and started going through my photos, and thinking about what I wanted to say, there was just too much to cram into a single post. Yesterday I talked about the history and purpose of the CBC; today I’ll elaborate on the results of our own outing.

Generally CBCs are quiet affairs, at least compared to summer surveys. In the summer a survey of an area that large could easily turn up 70 or 80 species, or even more if you’re in an area of diverse habitats. In the winter, at least here in the northeast, you’ll be lucky to get a few dozen with a good bit of hunting and the whole day at your disposal. We didn’t have the whole day, and the frigid temperatures meant we weren’t really into hunting, so we took what we could get. This is one of the pitfalls of the CBC, that there is no rigorous sampling method so effort varies from year to year according to the number of people available and how many hours they’re able to put in. Weather also plays a factor – the day is selected randomly in advance, usually for a weekend, and the count goes ahead rain or shine. A year with excellent weather is probably going to produce more birds than a year with heavy precipitation, for instance. These variables are all recorded so that they can be factored in in future analyses, and generally for monitoring surveys like this the data are looked at with a wider lens rather than on a year-by-year basis.

Because we only had a few hours available to us before the snow started falling and the roads got cruddy, and because we limited the amount of walking we did outside because the cold and wind could peel the skin from your cheeks if you stayed out too long, we had a small list, with just 16 species. Some of the species that were included on the list were star additions that we were pleased to see, though nothing exceptionally rare. Most, though, were common birds. Black-capped Chickadees were, unsurprisingly, the most common with 54 individuals counted. Part of this was because we made a few stops near bird feeders, which always draw in a crowd. But they’re also the most frequently encountered species in the winter woods, especially in evergreen stands. Evergreens, because they’re good cover, often have birds in them, compared to deciduous woods or open fields that are more often than not empty, so we made a disproportionate number of stops in coniferous patches. The above individual was part of a flock that were moving through a stand of young pines, bordering an open wetland filled with winterberry bushes sporting their bright orange berries.

We also had many of the usual suspects: Blue Jay, Hairy and Downy Woodpeckers, Red- and White-breasted Nuthatches, crow and raven, Red-tailed Hawk, Dark-eyed Junco. In addition to these were some less common though expected species: Brown Creeper, for instance, and Common Redpoll, the latter with 50 counted in three flocks, all flying overhead. We were pleased to find two small flocks of White-winged Crossbill, an irruptive species that is moving south in large numbers this year, being found in many areas south of the border that only get to experience them infrequently. We’ve been hoping to have some come to our feeder this winter, but so far haven’t seen any.

The most exciting birds to find, however, at least in my opinion, was a huge flock of waxwings. Dan discovered them during one of our leapfrog stops. He hustled back to find me (I was finishing up the person 1 segment) and grab his video camera from the car. There was an amazing number of birds in the flock, too many to get a precise count as they joined and departed the main body of birds perched in the tree beside the road. I made a quick estimate by eyeballing groups of fives to figure there were some 80 birds in the flock. Cedar Waxwings are not a species I see regularly in the winter, so finding such a large group of them was exciting.

They seemed to be feeding from buckthorn bushes that were growing between the road and a little patch of wetland. Common Buckthorn (Rhamnus cathartica) is an introduced species that’s become pretty well established through much of northeastern North America. It’s originally from western Eurasia and was brought to the New World as an ornamental garden plant. Though it can be invasive in some habitats, and causes problems for soybean farmers as it is the other plant host in the two-host cycle of soybean aphids, but it’s a great winter food source for birds, who feast on the shrub’s juicy black berries.

There is some misconception that because a chemical in the berries actually acts as a laxative in humans, the birds must therefore be unable to obtain sufficient nutrition from the berries and in the long-term could actually suffer or die from a diet composed mostly of them. Of course, that wouldn’t make much sense; shrubs produce berries for the purpose of attracting animals to eat them and thereby spread the seeds. Killing the animal who is spreading your seeds for you would be counterproductive, you’d be out of a courier in no time fast. Similarly, the parent plant “wants” the bird to take the seeds far from the parent plant, so including a laxative is likewise not a great idea. Bootstrap Analysis goes into more detail on the argument. She also points out that they’re a non-native plant so they’re not the top choice for planting in your garden, and provides a list of alternatives. But the fact that they do offer a viable food source for birds in the winter means that even though they’re displacing native plants, it’s not all bad.

When the waxwings weren’t feeding on the berries they were perched up in the tree, conserving energy or just digesting, I’m not sure. It was difficult to see the birds in the bushes very well, but the ones in the trees were conveniently out in the open. In scanning the flock, we discovered that about five of the birds were conspicuously different. They were bigger, grayer, and had reddish undertails. They were Bohemian Waxwings. This was an extremely pleasant surprise; the Winter Finch Forecast by Ontario Field Ornithologists’ Ron Pittaway had predicted this irruptive species to stay north this winter, as it specializes on mountain-ash berries in the colder months and the berry crops up north were good this year.

The birds were all perched up near the crown of the deciduous tree they were sitting in, which made it difficult to get good photos as they were not only backlit by the grey sky, but also tucked behind criss-crossing branches. And the photos I did get were all mostly of their undersides, which does highlight their nice rusty undertail coverts, but doesn’t show much of the rest of their plumage, including some fabulous lightning bolts running down the wingtips. These were only the second group of Bohemians that I’ve seen, since they’re an irregular, uncommon irruptive, and tend to move around a lot. I didn’t get great photos of the first group, either. I’ll admit that I’ve never tried super hard to track them down, though.

Bohemians breed in extremely small numbers in Ontario, restricted to the Hudson Bay Lowlands up north. The second Ontario Breeding Bird Atlas suggests that they’ve been expanding eastward a bit since the last atlas. Most of the species’ range is further north and west, however, including the northern part of Manitoba, Saskatchewan, and Alberta, up through the territories, over to Alaska, and south through the Rocky Mountains. It could be these were Ontario birds, but they could just as easily have come southeast from the main portion of their range, as they depart the northern part of their breeding range and will wander as far east as Newfoundland looking for winter food sources. Either way, these birds have made a long trip, and it was really nice to get to see them.

Holiday bird-hunting

Dan and I signed up to help with our local Christmas Bird Count this winter. We’ve both done CBCs before, but this was our first in our new home area. We signed up a bit late, so didn’t get our first choice area, the “corner” of the circle that includes the top of our road (unfortunately our house is just outside the circle boundaries). We were assigned a section north of town, an area that we’d only been through once or twice, so it was a new experience for us. This area isn’t chock full of birders (just like the general population, there tend to be more around urban centres) so there weren’t many teams covering the full area, and we had a large expanse of ground to cover. We could easily have spent the whole day out birding the region, but with the big snowstorm that was due to roll in this afternoon, we only got a few hours in in the morning before having to pack things up. What we did do was mostly by car, some 50 km (31 miles) worth of road, though we did hike about 3.5 km (2.2 miles) in small segments here and there where the habitat looked promising.

Christmas Bird Counts are an annual, volunteer-driven bird monitoring project that occurs continent-wide during the month surrounding Christmas. They have their roots in the old 19th century pasttime of sport hunting. During that period hunters would compete in an annual Christmas tradition to see how many birds they could kill in a day (very few of these were likely ever actually used or eaten, and this sort of competitive and senseless massacre was a large part of what drove the Passenger Pigeon extinct). Watching birds and allowing them to live instead of shooting them for sport or science was just coming into its own at the end of the 1800s. An ornithologist named Frank Chapman proposed that perhaps instead of competing to see how many birds they could kill in a day, they could see how many birds they could count in a day. I don’t know whether Chapman’s motivations were out of sympathy toward the birds or concern over long-term depletion of populations, but either way they’ve inspired something big.

The first counts took place in 1900. There were 25 circles that year, and just 27 participants to count the birds in them. Toronto, Ontario, was one of those first 25, along with one in New Brunswick, the only Canadian representatives. All but 3 of the original counts were in the northeast. Those 27 people found some 18,000 birds of 90 species during the counts. The Christmas Bird Count has grown exponentially since then. Last year almost 60,000 people joined in to participate in 2100 counts across the Americas. They counted nearly 58 million individuals of 2267 species of birds. Competitions these days are less about giant numbers and more about rareties, those birds that are out of place for the time of year and location. The person who pulls up a slowpoke warbler on their snowy count here in southern Ontario gets a clap on the back. Even if a participant wasn’t the one to find the special bird themselves, there’s some thrill in knowing that these birds are hanging around in your area.

Of course, there is science behind all this fun. The purpose of the counts these days is to act as a monitoring tool for wintering species. Especially in the north the CBC can be a valuable tool to track species that tend not to be easily accessible at other times of year because they breed further north. Even resident species benefit from the monitoring, though, and in combination with Breeding Bird Surveys and Migration Monitoring the CBC adds a valuable component to monitoring efforts.

We saw tracks of Wild Turkey, but not the bird that made them.

I’m using that word a lot, “monitoring” – what does it mean? There are two types of scientific data collection that helps birds and other animals. The first is direct research, where people go into the animal’s habitat with the goal of answering a particular question. The question may be as simple as “how many young does this animal have” or “where do they build their nest” or “who does the majority of the parental duties”, or it may be as complex as “what effect do military training exercises have on the breeding success of birds using military bases to nest?” or “how often do extra-marital copulations occur and what percentage of a female’s offspring are fathered by someone other than her mate?” All of these questions come to bear when deciding on management practices or designating natural areas for protection, or for intervening to help save a species in decline.

We also saw lots of deer, perhaps 7 or 8, but they don’t count.

And that’s where monitoring comes in. How do we know a species is in decline without data to show its numbers dropping? The three primary monitoring surveys are complemented by an array of smaller, often local, projects and efforts. Project Feederwatch, the Marsh Monitoring Survey, and local breeding bird atlases are other monitoring projects that provide valuable data to this end. Monitoring projects are ongoing and rarely have the showy results that funding agencies like to see come of their money, so it’s often difficult to get money for these sorts of projects. And yet, they’re every bit as important as the one-off research projects for providing valuable data. While research projects tend to be carried out by academic institutions or employees of bird observatories, most monitoring projects are primarily volunteer-driven. Fortunately, as the CBC shows, there are no shortage of people willing to participate.

Each count circle is 15 miles (24.1 km) in diameter, which equals about 177 square miles (452 sq km). That’s a lot of ground to cover by foot! I’m not sure why they chose to make the circles so large when the CBC was first established, particularly since they didn’t have many participants back then to scour the area. The segment that Dan and I covered was just a fraction of that, maybe 80 sq km (31 sq mi), but it was still a huge chunk of land for just two people, and hence why we drove most of it in the three and a half hours we had before the snow started falling. We got out of the car a few times, usually dropping one person off at point A and then driving half a kilometer up the road to point B, where the second person would park the car and walk up ahead; person 1 would reach the car and then drive ahead to pick up person 2 from wherever they’d managed to reach. It was bitter cold out, -12 C (5 F) before the windchill, and I think something like -17 C (1.4 F) with it. About ten minutes outside was about all we could manage before we’d have to climb back into the car and thaw out our cheeks and toes. We brought Raven with us, rather than leaving her at home stuck in her too-small crate (I’ve been looking for a larger used one online, since they’re not cheap, but every one I’ve contacted so far has already been sold or hasn’t responded). She’d walk down the road with person 2, on her leash, when we stopped to do a leapfrog. She enjoyed the outing, though she was happy to get in the car again after each walk outside!

Tomorrow: what we counted.

They’ve got some gall

Here’s a topic that is frequently written about at this time of year: goldenrod galls. They’re common and they’re conspicuous, and they tend to grab people’s attention. Last winter I remember reading a few posts by various people on the galls. Most of the time the ones that are written about are the round ones that resemble a snake that has swallowed a ping pong ball. But there’s actually four different types of goldenrod galls, of which the ping-pong sort are just one. One affects the foliage at the growing tip of the plant, and the other two are also stem galls, but elliptical in shape, as if the ball the snake swallowed got deflated. It was while out walking Raven this afternoon that I came across a few of these. Strangely, no ping-pong galls, which were ubiquitous in the GTA (and perhaps here, too, just not along the road section I chose to walk).

I picked up three and brought them home with me to check out. Ping-pong galls are often the target of chickadees and woodpeckers, which bore into the gall to get the tasty grub inside, but you don’t see that as much with the smaller galls. I saw no real evidence of predation, so I figured the gall’s contents were likely still intact, although it’s possible that the small hole, as in the photo above, was evidence that the adult had left.

When I opened up the first one, there was an empty pupal case inside. This had obviously belonged to a moth, now departed. You can see the segments of the abdomen clearly defined in the case, as well as the wings, which wrapped around the front of the moth’s body. The ping-pong galls are the product of a fly larvae, but both elliptical galls host moth larvae, but different species. The moth in this one is the Goldenrod Elliptical-gall Moth, Gnorimoschema gallaesolidaginis. This moth lays its eggs on dead foliage around goldenrod, and in the spring the larva hatches and crawls up a goldenrod plant, where it bores into the growing tip and down a few inches through the centre of the stem, where settles down for the summer. The plant, in response, forms a thick layer of stem tissue around the invader. The larva pupates in the late summer and then emerges from its home in the fall to mate and start the cycle over again.

In order to make it easier for the adult to leave, the larva will bore a hole out to the outdoors and then plug it with a silk trapdoor that is shaped the same way you would carve the lid on a jack-o-lantern – beveled, with the inside smaller, so that the lid can’t fall inside. This makes it easy for the moth to leave when it’s time, but hard for a predator to get inside. You can see the round plug in this gall, and also the one in the second photo. You can also notice in the photo with the pupal case that it is attached to a mat of silk at one end. The silk actually blocks the entrance that the larva came in by, which helps the adult to find the plugged exit hole and not go out the wrong way.

I was a bit surprised to discover the second elliptical gall had a larva in it, not an empty pupal case. Poking around the ‘net a bit, it turns out there are two species that create elliptical galls. The second one is the Goldenrod Gall Moth, Epiblema scudderiana. This species is different in that it overwinters as a larva and pupates in the spring, emerging as an adult in May and June. The galls are hard to tell apart from those of the Elliptical-gall Moth, the main feature being that they lack the exit plugs that the other species makes. They can both occur in the same patches of goldenrod, and sometimes even on the same goldenrod stem. Next time you see a goldenrod stem with two elliptical galls you can check to see if they’re different species.

The third gall held neither a pupa nor a larva. Instead, it appeared to hold the cocoon of another species, perhaps a type of wasp larva that had usurped the chamber and fed on the moth larva. There are four species that will parasitize the moth larva, but it may be Calliephialtes notandus, which targets the Goldenrod Elliptical-gall Moth and other stem-living moth larva. The wasp larva eats the moth larva from the outside (as opposed to some wasp larvae where the egg is laid on or in the host and the larva eats the host from the inside out), and eventually pupates in a tough, light brown cocoon shaped like a fat grain of rice. The adults emerge in September, so this winter case, like the moth one above, is also empty. You can see the tunnel at the top of the gall (on the right) where the adult would probably have emerged from.

I really lucked out with the three that each one contained something different, completely by chance. It’s funny that I’d never stopped to check out the inhabitants before, although you see the galls all the time, aside from one lab project we did in first-year biology where the class trooped out to the field behind the campus to collect some ping-pong galls and assess the contents. Primarily what I remember from that afternoon was how bloody cold it was outside that day…

Today at Kingsford – Evidence of beavers

What a difference a day makes. Yesterday morning Dan and I took Raven and walked down the lake, across the ice. The entire lake was frozen solid, shore to shore, with a thin layer of soft, dusty snow settled on top of it. We could probably have taken our skates if we wanted. This morning the weather was warmer, and it rained all day. Instead of a thin layer of snow there was a layer of water sitting on the ice, reflecting the sky and the skeletons of the trees on the opposite shore. The riverbed channel in the middle of the lake was starting to thaw out and thin.

This photo is from yesterday, when the frozen lake was an open, pristine expanse of snow, untouched, crisp and clean. These are my favourite snowscapes, broad, open spaces, newly fallen snow with no tracks or blemishes yet. Thick, wet snow outlining the branches of the trees is a very close second. It’s been a while since I’ve seen the lake from this point of view, not since we were able to take the boat out.

We noticed this while we were out. The thing that caught my eye was actually the change in colour of the ice where Dan’s footsteps had scuffed away the snow. Most of the lake is covered in cloudy white ice, but for a couple of steps the ice was clear and dark. Taking a closer look I could see that there was a noticeable track in the ice going back to the shore, and, following its length, a beaver lodge at the shore’s edge. There are several such lodges along the shores of the lake. I’m not sure how many pairs of beavers there are here, and therefore how many of these lodges are occupied, but it appeared that this one has active residents. The change in colour of the ice was due to the activity of the beavers as the water was freezing, keeping a narrow channel open as they moved to and from the lodge. Probably most of the ice began to freeze overnight, when beavers are more active, and then once they retired in the morning their channel finally got a chance to close up.

I tend to think of beavers as being semi-hibernators over the winter, but actually they remain active all through the cold months. In the fall they build up a substantial larder of branches and small tree trunks, stored underwater where they can access it from the lodge even when the water surface is frozen solid. Beaver activity peaks in the spring and fall; in the spring they are repairing their structures that may have sustained damage in the harsh winter conditions, in the fall they are stockpiling food for the winter. Beavers can hold their breath for up to 20 minutes, but like all land-dwellers must come up for air at some point. Sometimes the water level will drop after the ice has formed, creating an air pocket between the two, or if the ice is thin enough the beaver may be able to create a breathing hole, but more often it will need to return to its lodge. To provide air circulation and allow fresh air to enter the lodge, beavers don’t pack mud on to the top of the dome, which creates a sort of ventilation “shaft”. I didn’t look for it yesterday, but one website suggests if you look closely on a cold day you can see the wisps of warm, moist air from the beavers within escaping from the little gaps in the peak of the lodge.

Seasonal waterfront homes

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.