Jan 012015
 

If you think from reading the title that you are about to read an excerpt from a steamy romance novel, I am afraid you might be disappointed.
If, however, you have an interest in where moths go during the cold months, then I hope you`ll find the following of interest.

Frozen, quiet, and white, is the landscape at this time of year.
The silent, still air may, for a time, be infiltrated by the laughter of a nuthatch, the flute-like snort of an alarmed deer, or the the warble
of a pair of ravens as they roll through the sky together in early-season courtship. And what about the night? Apart from the occasional hoot of an owl, the mournful lament of distant coyotes, or the sudden crack of a tree as it freezes, much of the winter night seems to be truly asleep.

Although there actually is a lot going on during this sleepy season, there are moments when the lack of sounds brings back not-too-distant memories of the seasons of more abundant audible presence. What natural sounds do we not hear during the winter?
“Most”, I think, would be the best word to answer that question. For instance, many more than half of the bird species that breed here, have flown to distant southern lands, and have taken all of their various chatter, chirps, and songs with them.

Spring-singing amphibians (the frogs and toads) too, have disappeared into mud and leaf litter, and have retreated into a silent absence. We generally do not hear anything from them for months. (Though I now have heard at least once, a spring peeper within every month on the calendar. This will occur in any of the colder months if the temperature rises enough above freezing, and maintains for enough consecutive days and nights, that a few of the little frogs are able to thaw out and utter occasional and very weak “peeps”).

So, what about the insects? In the frozen grip of winter, we no longer hear the piercing grind of the cicadas of summer, the chirps of crickets of early autumn, nor the springtime rattle of June Bugs as they bang about out on the porch after dark. Similarly, (and one of my favorite sounds), the whirling rush of moth wings as they circle my head beneath the porch light, is absent now as well. But, on this frozen January day, “Where have all of those moths gone?”, you might ask. Well, not only are they here, but depending on the species, most are over-wintering in various stages of their life cycles.

Some species, (like the cutworms and other noctuids), and depending on the species, over-winter as adults, or as eggs, as larvae, or as pupae,,, and many are indeed alive and well in the Kawarthas right now! Other species may only be here in one form or another throughout the winter months, while others are believed to only migrate into Ontario each spring/summer season. In the case of the latter, it could also be that some migrate out of the area before winter arrives, and/or otherwise die off here completely each fall.

It is not at all uncommon to see the familiar “Woolly Bear” caterpillar on a mild late autumn (or even mid-winter) day. I have seen them crossing roads, crawling about in the garden, and sometimes moving around through piles of stacked firewood.
And most often during the same milder days that I have heard the much-out-of-season Spring Peeper frogs call out.

Woolly Bear caterpillars are the larval stage of the Isabella Tiger Moth, which is a member of the family “Arctiidae”, and this species over-winters in the larva stage. There is an old wives’ tale that suggests that you can predict the severity of the coming winter, based on the thickness ratio of brown to black colour bands of the Woolly Bears’ bristly coat. Though it may be fun to fancy such an idea, it is simply not true. As the larva sheds its skins throughout the fall, they begin with much more black, and acquire more brown in the last skin stage, (which is called an instar), as they head into late fall. So, if you see a Woolly Bear in September, it might indicate the approach of an entirely different kind of winter, than if you saw the very same individual in November.

Woolly Bear - Wikimedia

Woolly Bear – Wikimedia

A large number of moth species found in this area over-winter in the egg stage. About thirty of these are members of one of my favorite groups – the Catocala, or “underwing moths”. As winter weather deposits snow, ice accretions, and all manner of frozen water upon the branches of trees, beneath the icy coating lies much tiny, suspended life in the form of fertile moth eggs. “Moth seeds” is what I like to call them.

I have, and with great difficulty, managed to find these eggs on occasion, but it is not something I would recommend that one should try, unless one has at least as much patience, as they do a desire to see them. They are most often found in cracks and furrows in the bark of outer branches, where they were “glued” by the female moth with a special adhesive that each egg has to pass through as it is layed. As is the case with all the underwing moths, the eggs have been layed on the various host trees, specific to the particular species of moth, so that when they hatch in May and June, (and once the leaves are out), the proper food is just a short crawl away for the tiny larvae.

So, enough explanation about the very difficult-to-find moth eggs in winter. Lets look for something much easier to find. The Saturnids, (silkmoths), spend their winter here in the pupa stage. Some species in this area, like the Imperial Moth, the Pink-striped Oakworm Moth, and the Rosy Maple Moth, are “earth-pupators”. These are some of the many species of moths that, as larvae, burrow into leaf litter and soil before splitting out of their final larval skin and thus, become a pupa. They wiggle about until they have shaped somewhat of a small, earthen chamber, which to a point, hardens some by the time the pupa has completely transformed . In the case of the saturnids, they will stay in these chambers until the earth has warmed enough in late spring and early summer, and then will split out of the pupal shell, find their way back to the surface, and climb something high enough that their wing veins can fill with fluid and harden without worry of drying mis-shaped, as they might if they were to come into contact with something inhibiting free, open-air expansion.

Some of the other silkmoths, (the species of silk-spinners giving the group its common name), as mature larvae, will find a place on a twig, and spin a silken outer cocoon. Once it has completely covered itself in its outer “sleeping bag”, it will spin a sort of cylindrical container inside the rough outer layers. The inner wall of this will become very hard and smooth. When the caterpillar is ready, it will shrink somewhat, and then split out of itself, and become a naked, brown pupa. This too, will soon harden, and although it may wiggle inside a little when warmed by the sun, it will otherwise be still until spring. Species that you may spot in the winter either attached lengthwise on, or hanging from branches, are the cocoons of Cecropia Moth, Columbia Silkmoth, Polyphemus Moth, and Promethea Moth. The cocoons of others like the Luna Moth (and sometimes Polyphemus), though usually wrapped with silk in the green leaves of the host trees in the late summer, tend to fall to the forest floor in October with the rest of the leaves that fall from the trees then. They are not so often well-secured by silk to branches as some of the other species mentioned.

The Cecropia, Columbia, and Promethea cocoons however, have a strong silk wrap, and to the trained eye, can be quite easy to find in the winter as they are visible on leafless trees. Promethea and Columbia larva rarely wander when it comes time to spin their silken cocoons, and most are usually found on the same individual tree whose leaves nourished the caterpillars throughout the summer. The larvae of the Columbia Silkmoth consume the deciduous needle-like leaves of the Tamarack, and the silken cocoons of that species are most often found on the upperside of very horizontal Tamarack branches in winter.

The hanging, spindle-shaped cocoons of Promethea are most often found hanging near the tips of their two favorite larval host trees – the White Ash, and the Black Cherry. I have found them on a few other species before, but more than 90% of them in this part of the world can be expected to be found on the ashes and cherries. There is often from one to a few Promethea cocoons on a tree, but once in 2007 I found no less than nineteen cocoons on a single small Black Cherry tree!! (Though some were old and vacant, it should be noted that the whole combined lot no doubt represented at least a few generations).

Promethea cocoon close-up - Tim Dyson

Promethea cocoon close-up – Tim Dyson

The largest cocoons, (out of which will eventually come the largest moths), are made by the Cecropia larvae. They will either stay put on their host tree, or some will wander off a fair distance before finding a branch or twig upon which to spin a winter sleeping bag. These can be quite large, (up to 4X10cm), and more often than not, are found to be rather solitary compared to Promethea cocoons. If you are hoping to see Cecropia cocoons in winter, groves of Speckled Alder (a popular larval host tree of the species) along lakeside marshes, and in river floodplain habitats are very often good places to start.

If you happen to find one of these, (and it’s minus 25 out when you do), don’t worry too much for the “moth-to-be” contained within. Even though the naked little pupa inside is only wrapped in silk,,, it is wrapped in so much of it, (and is cold-blooded), that it is far more protected from the cold than you are in your many layers of heavy winter clothing. Even if you feel sorry for the moth inside, it is not a good idea at all to bring the cocoon indoors. Once it spends some weeks in a warmed house, it will complete development, and the moth will emerge many weeks before it would have done if left outside in the natural environment where you had found it. It is best to just leave it be, and return, (daily if you can), in late May if the spring has been particularly warm, or during the first week of June, if it has been a cool-to-average spring. They emerge in the morning, and you can see them then, in full splendor! Later that evening, they will take off, mate, and continue their kind.

Oct 092014
 

At the rate I’ve been going through sunflower seed this fall, a second mortgage is looking like a distinct possibility. The dozen or so Purple Finches that have been with us since mid-September have been particularly voracious eaters. However, I’m not complaining. Although these attractive birds show up at our feeders most falls, rarely do they linger this long. Anyone who feeds birds on a regular basis knows that the number of individual birds and the variety of species showing up at feeders varies widely from one year to the next. Last year, for example, things were quiet. In 2012-2013, however, large numbers of winter finches – redpolls, siskins, grosbeaks, etc. – graced us with their presence. Why is it that finch numbers fluctuate so widely? The short answer is food.

Pine Grosbeak - Wikimedia

Male Pine Grosbeak – Wikimedia

Winter finches move southward when there is a shortage of wild food – mostly seeds and berries – in their breeding range in the boreal forest of northern Ontario and Quebec. If seed crops are good in the north, the birds stay put. If food is lacking, however, they will sometimes fly thousands of kilometres to find it. Whether they actually choose to spend the winter here in central Ontario and the Kawarthas depends mainly on the abundance of wild food crops here.
Since the fall of 1999, Ron Pittaway of the Ontario Field Ornithologists has prepared an annual forecast of what winter finch species are most likely to make an appearance in southern and central Ontario during the upcoming fall and winter. The forecast is based on information he collects on the relative abundance of seed crops in the boreal forest. Much of the data comes from Ministry of Natural Resources staff. The key trees affecting finch movements are spruces, birches and mountain-ashes.
So, what is the seed crop situation this year? According to Pittaway, spruce cone crops are excellent in the southern James Bay region and east across north-central Quebec. However, they are mostly poor elsewhere in the province, including the Kawarthas. As for birches, the amount of seed is poor to average. American Mountain-ash trees, on the other hand, have produced a bumper crop of berries across much of the north, with the exception of northeastern Ontario. What all of this means depends on the bird species.

Pine Grosbeak – One of our most beautiful finches, Pine Grosbeaks should make a small flight into the Kawarthas this winter, given the lack of mountain-ash berries in northeastern Ontario. Some may turn up at local feeders looking for sunflower seeds but most often you will see them feeding on European Mountain-ash and ornamental crabapples. This surprisingly tame species can be quite common right in Peterborough.
Evening Grosbeak – Small numbers of Evening Grosbeaks should move south this winter into southern and central Ontario and may show up at feeders. Their numbers, however, are now much reduced from the population peak that occurred from the 1940s through the 1980s. The high population was linked to large outbreaks of spruce budworm, which occurred at this time. Budworms provided an unlimited source of protein for the grosbeaks, allowing them to raise a lot more young than usual. A decline in grosbeak numbers began in the mid-1980s when the size of annual budworm outbreaks decreased. Ontario’s breeding population of Evening Grosbeaks is now believed to stable.
Purple Finch – Due to poor seed crops in central and northeastern Ontario, most Purple Finches are likely to migrate out of the province this fall and south into the U.S. Many are passing through the Kawarthas right now. In the 1960s and 70s, Purple Finches were much more common than they are today. As with Evening Grosbeaks, the principal cause of the decline may be the absence of large outbreaks of spruce budworm.

male Purple Finch - Wikimedia

male Purple Finch – Wikimedia

Crossbills – Red and White-winged crossbill specialize in removing seeds from the cones of conifers. We may see some Red Crossbills this winter in areas of the Kawarthas where Red and/or White pines have produced a heavy cone crop. As for White-winged Crossbills, they will be mostly absent this winter from central Ontario, given the lack of cones on spruce trees. White-winged Crossbills move east and west like a pendulum across North America searching for bumper cone crops.
Common Redpoll – Because the seed crop on birches varies from poor to only average in the boreal forest, a moderate to good flight of redpolls is expected this fall and winter as the birds leave the north in search of food. The question is whether there is sufficient seed on the birches of central Ontario to persuade them to linger here. At feeders, redpolls prefer Nyjer seeds. Watch for Hoary Redpolls, too, mixed in with the flocks of Common Redpolls.
Pine Siskins – Siskins are expected to move east and west this fall searching for areas with abundant spruce cone crops. This means that many will probably spend the winter in north-central Quebec where spruce crops are excellent. However, those birds that fail to find adequate cone crops will probably wander south and some may turn up at local feeders. Like redpolls, siskins are attracted to silo feeders offering Nyjer seeds.
Blue Jays – According to Pittaway, the acorn, beechnut and hazelnut crops were fairly low in northeastern, central and eastern Ontario this summer. We can therefore expect fewer Blue Jays at feeders , since most will migrate out of the province in search of these food items elsewhere. That being said, I’ve certainly noticed good acorn crops on many of the oaks in the Kawarthas, so it will be interesting to see if a number of our local jays decide to stay put.
Red-breasted Nuthatch: This is a species that depends primarily on conifer seeds, so cone crop failures can cause these birds to move elsewhere in search of food. Some Red-breasted Nuthatches began wandering southward in mid-summer this year and more are expected to follow. Movements of Red-breasted Nuthatches into southern and central Ontario is usually a sign that some of the northern finches will also be showing up. At feeders, this species prefers black oil sunflower seeds, chopped peanuts and suet.

Bohemian Waxwing: Most Bohemians should stay in the north this winter, because of the large berry crop on mountain-ash. That being said, we almost always see at least a few flocks of this species in the Kawarthas in winter. This may be partly due to the local abundance of European Buckthorn, a non-native shrub that produces a large berry crop nearly every year. Bohemian Waxwings are also attracted to European Mountain-ash and ornamental crabapples. In recent years, these handsome birds have expanded their breeding range east across northern Quebec.

Bohemian Waxwing (Karl Egressy)

Bohemian Waxwing (Karl Egressy)

Project FeederWatch
If you feed the birds, you can support bird research and conservation at the same time. Join Project FeederWatch and share information about which birds visit your feeders between November and April. This will help scientists at Bird Studies Canada and the Cornell Lab of Ornithology track changes in bird numbers and movements. Participating is easy. Just count the numbers and kinds of birds at your feeders, and enter the information on the Project FeederWatch website (or on printed forms). Last season, more than 3100 Canadians took part in this North America-wide program. More information can be found at http://www.birdscanada.org/volunteer/pfw/ or by calling Bird Studies Canada at 1-888-448-2473.