Tag Archives: Blue Jay

Sunday Snapshots: Being Harried

Hairy Woodpecker - female

NB: I didn’t get a chance to post these on actual Sunday, as our internet service provider seemed to be suffering an outage. So they’re going up Monday, but I’ve backdated them to Sunday.

Here are another couple of species that have been frequenting our feeders, but that I didn’t have room to mention on Friday. Clearly, the female Hairy Woodpecker (above) rules the roost.

Hairy Woodpecker - female

Hairy Woodpecker - female

Hairy Woodpecker - female

Hairy Woodpecker - female

Monday Miscellany

Country road in spring

It’s amazing just how fast the trees leaf out once they start. Just two weeks ago I was noting the late afternoon sun glowing through the sprinkling of leaves on the saplings across the road from the house. Now, I can barely make out the neighbour’s house, which was so apparent in winter. By June, I won’t be able to see it at all. All manner of plant life has greened up or is hard at work at it. Some shrubs are completely leafed out, while the tall ash trees are only just starting. Like the creeks that start tumbling over their rocky beds at spring melt, once spring arrived, time seems to have picked up speed and is rushing by.

Blue Jay

We’ve had a fair bit of rain over the course of the last week. It seems to have gotten all the wet out of its system now, however, and we’re forecasted to have mostly clear skies the rest of the week (whether it remains that way remains to be seen). Although all that rain was undoubtedly part of the reason behind the green explosion, the animals were less than happy about it. This Blue Jay, for instance, was looking a bit bedraggled as it visited the feeders one afternoon.

Mink Frog

The rain has made the ground near our dock rather soggy. As Dan was flipping his boat over one day last week to try to locate a leak that had gotten worse over the winter, he disturbed this guy from the pool of water around the boat. I spent a lot of time debating the identity of this guy. The bright green upper lip and speckled underbelly should make it easy to ID, I figured. I think that it’s a Mink Frog, Rana septentrionalis, but it could also be a Green Frog, Rana clamitans. I couldn’t figure out a definitive ID characteristic that would rule one out based on the photos I have. A Mink Frog would be a “lifer” for me, a species that I’d never encountered previously. In Ontario they tend to be found further north than the GTA where I grew up, but we’d be at the southern edge of their range, here. They’ve been recorded over in the Park. I’m leaning toward Mink because of the small eardrums, dorsal ridges that terminate halfway down the back, and lack of strong barring on the back legs, but I get the impression these are all somewhat variable features.

Water bug, Belostoma sp.

Before Dan flipped over his boat, he bailed out some of the water. And sitting in the water was this guy. I believe it’s a water bug in the genus Belostoma. It was rather large, about an inch long, and quite active within the container Dan had scooped it into. This group of water bugs are among those where the female lays her eggs on the male’s back in the spring. He “broods” the eggs, keeping them clean of fungus, protecting them from predators, and making sure they’re well oxygenated (by doing “push-ups” at the surface of the water). I’m not sure if the lack of eggs on this one means it’s a female, or just a male that hasn’t been laid on yet. I did notice, however, in examining the photos on my computer, that it’s sporting a bunch of red mites.

Bolitotherus cornutus

I found this strange beetle clinging to a piece of driftwood beside my moth trap one morning. I wasn’t sure if it was alive, as it fell off the wood when I touched it, and sat with its legs curled under it. I set it on a shelf in a vial for a couple of hours as I sorted through my trap and photographed the moths I’d caught. When I returned to it, it was sitting in a different spot in the vial, and its legs appeared to be out. As soon as I picked up the vial again, however, it fell over and its legs curled underneath it again.

I pulled out my trusty Kaufman Guide to Insects (I love that book, have I mentioned that?), and there it was at the bottom of page 193: Bolitotherus cornutus. Looking it up on BugGuide.net reveals its common name to be Forked Fungus Beetle, or sometimes Horned Darkling Beetle. The two horns are projections from its thorax, and are used in “battle” with other males to win females (I’m not sure the purpose of the orange “hairs”). They are associated with bracket fungi of hardwoods such as maple and beech. The Kaufman guide makes a note that they are adept at “playing dead”, so I guess that’s what my beetle was doing whenever I disturbed it. Was pretty convincing!

Unidentified bracket fungus

While out with Raven today I encountered this bracket fungus projecting from the side of a stump. Just recently I had read over at Huckleberry Days about Dryad’s Saddle, Polyporus squamosus, a stalked bracket fungus that appears about now, so I thought, “Aha! A Dryad’s Saddle!”. I took a documenting photo and returned home. I pulled out my mushroom guide just to confirm and look up a couple of life history details about the species, and now I’m not convinced that it’s Dryad’s Saddle after all. All the photos I can find on the web for the species show it being concave where it attaches to the stalk, rather than convex like my fungus. I searched through the guide a couple of times and poked about the ‘net, but couldn’t come up with an identity.

Bee fly

Very close to the same spot, I stood and watched this bee fly hovering at several Spring Beauties at the side of the road. It was much oranger than previous individuals I’ve seen, and I wondered if it was just a dark Bombylius major, the species I’ve seen before, or a different species. I gather the half-light/half-dark wing markings are fairly distinctive, and seem to only be shared by B. major and B. mexicanus. It’s hard to make out the specific pattern of dark, but I’m leaning toward B. major.

Crab spider?

I have no idea what this spider is. Not being insects, they’re not usually treated in much depth in the usual insect guides, although Stephen Marshall’s Insects doesn’t do too badly. It looks like it might be a type of crab spider, but I’m not sure. I’d knocked it off the branch of a tree onto a white sheet when I was out looking for beetles (as per a post by Ted of Beetles in the Bush that suggested if you go around thwacking some branches in the spring, it’s possible to discover some beetles you might not normally encounter). I’ve only gone out the once and thwacked half a dozen branches before I was disrupted by the arrival of a real estate agent who was coming to take photos of the house, and then it rained much of last week. Now that the weather is nice again I plan to give it another try.

Birdwatching

A few animals from a little closer to home… with the nicer spring weather the cats have been allowed to go outside in their harnesses to sit in the long grass, enjoy the sunshine, and watch the birds. They’re tied to the deck with short 10-foot leads, so they’re not really a threat to anything except perhaps the odd bug. Both for the safety of wildlife and the cats themselves, I never let my cats roam about outdoors, so this is about as outdoor-cat as these guys will get. They enjoy it, though. Despite the chipmunk who thumbs its nose at them by foraging on fallen seeds under the birdfeeder five feet away.

Fish eats cat, fish spits up cat

Fish eats cat. Fish spits up cat.

Water dog

Since late winter, when the snow was just starting to melt, Raven has been taking an increased interest in water. At the first start of ice breakup, she’d paddle her feet in the shallows of the lake, but it’s taken her a while of gradually working up to letting her feet leave the security of the ground. Even when she started doing that, she’d only push forward half a body length, and then quickly turn around to paddle back. After once or twice of that, she wouldn’t go after sticks that were further out anymore, she’d just look at you and whine. We’d taken her out in the boat a couple times and “thrown” her overboard, and she’d paddle back to shore just fine, but was reluctant to go in of her own accord.

Then, a couple days ago, it was like she had an epiphany. We’d thrown a couple of sticks for her just out of reach from where her feet could touch bottom, and she’d pushed off to grab them, but turn quickly back around. She showed a bit of willingness to go a bit further, and so we got her to do two body lengths, and then three. Then Dan suggested throwing the stick way out and seeing if she’d go for it. So I tossed it four or five meters out, and she struck right out to retrieve it.

Water dog

Within the course of five minutes, she was suddenly paddling all over the place like a bonafide water dog. Not only that, but once she realized she wasn’t going to drown if her feet left the bottom, she discovered that hey – I actually like this! Now when we take her down to throw sticks for her, she’ll jump right in the water and start paddling out before you’ve even tossed the stick out. Quite a change from the puppy who was reluctant to even get her feet wet last fall!

More on Blue Jays

Blue Jay, Cyanocitta cristata

Since Dan got his Master banding permit, we’ve put up a few nets to get a start on some of our planned projects. I mentioned the owl monitoring already in an earlier post. This morning we opened a net that we set up near our feeders. Dan goes into more detail on the purpose of the project, but essentially it’s to learn more about the local winter ecology of our resident birds – things like population sizes and demographics, survivorship over the winter, and general health of individuals (hopefully if we’re supplementing their diet with feed they’ll all be in good health, but it may lend some insight into the food resource abundance outside of the feeders).

There’s a lot of information that’s either extremely difficult or impossible to obtain without using banding studies. Two such pieces of info were evident from our efforts this morning. The first was that there were a lot more Blue Jays visiting our feeders than we’d first thought. By visual counts, simply watching the feeders and seeing who was around, we guessed there were perhaps 5 or 6 coming for seed. This morning, however, we caught no fewer than 8 separate individuals in the net, and later on, once we’d closed the net for the day, saw an additional 3 together at the feeder who had no bands, making a minimum of 11. We observed some of the banded individuals coming to the feeder again a short while later. Free food is hard to pass up! Evidently they weren’t too put off by the quick banding process.

The second thing we learned is that there’s an unusual proportion of adults to young birds among them. In an average fall, at an average banding location, one might expect to capture about 80-90% hatch-year (HY) birds – that is, birds that were hatched in this calendar year. The remaining 10-20% are after-hatch-years (AHY) – the adults who were parents this calendar year. Among our 8 Blue Jays captured this morning, a whopping 6 – 75% – were adults. This could mean either it was an exceptionally poor breeding year for Blue Jays in our woods and they didn’t raise many offspring, or the offspring have all dispersed or flown south, leaving just the adults to spend the winter here. It’s hard to know the reason for sure, although seeing what the proportions are come spring (after any migrants have presumably returned) will help to answer the question.

Blue Jay ages

You can tell the difference between the age classes of Blue Jays fairly easily. HY birds still have many of their “baby feathers”, that is, the set of feathers that they grew in while they were in the nest. They grow these feathers very quickly, because they want to limit the amount of time that they’re flightless and vulnerable to predation. However, because they grow them in all at once, and feathers are very energetically costly to grow, these “baby feathers” are of very poor quality. They’re generally rather coarse and dull, and will fade and wear down rapidly. Most songbird species have a pattern of moult whereby the HY birds will replace a portion of their feathers before the winter to see them through until their next moult (for some birds, this will be spring, but for many others they’ll have to wait until next fall). You can examine the feathers of a bird’s wing to see if it’s got any “baby feathers” – and most species have a very specific replacement pattern so it’s easy to know what to look for.

In the case of Blue Jays, the characteristic feathers are these small, outer feathers mid-way up the wing. They’re the little feathers that cover the sheathes of the long primary feathers (appropriately called the primary coverts), and the feather that comes from the thumb (the alula). In the above photo, you can see the left-hand bird, the AHY or adult, has very distinct barring to these outer feathers, and the colour is approximately the same as the larger neighbouring white-tipped feathers (the greater coverts, which cover the sheaths of the long inner secondary feathers). The right-hand bird, the HY or youngster, has relatively unmarked outer feathers which are a duller colour than the rich blues of the white-tipped greater coverts.

Blue Jay

I love Blue Jays’ wings, the blue colour in them is simply surreal. While most feather colours are created through various pigments, blue and green different. Like the sky, blue is created through the refraction of light, not the absorption of it. A red feather will still look red when lit from underneath, but a blue feather loses all of its colour – check out this page for some neat photos demonstrating this. Likewise, if you grind up a red feather, you have a pile of red dust, but grinding up a blue feather does not produce blue dust (it will more likely be brownish or grayish).

The exact light-scattering mechanism employed in these blue feathers has traditionally been assumed to be similar to what happens in the sky – the light hits the microscopic structures and then scatters in all directions, with just the blue coming back to your eye (so why don’t you see red or orange when viewed at a sharp angle, like sunsets, you ask? Good question, and I don’t know the answer.) A paper published in 1998 argued that the blue was created through a different scattering method, called interference or coherent scattering, whereby the light wavelengths break up and then come back together again, and the way they meet up again all the colours cancel themselves out except for the blue.

Whichever it is, the end result is that it’s a colour produced through structure, not pigment. And it’s pretty amazing. Can you believe so many people simply look past these guys, desensitized because they’re common?

Bold and bossy

Blue Jay, Cyanocitta cristata

When we first put the feeder up, the chickadees were the most common birds coming to visit, by virtue of the fact that they were the only ones who knew about it. Now that the word has spread, and we’re getting more species, the Blue Jays might be more frequent visitors. Undoubtedly, they’re the ones going through the most seed.

Blue Jays (Cyanocitta cristata) are real characters. They belong to the family Corvidae, which includes the jays and crows, generally felt to be one of the smartest groups of birds. For instance, jays often learn the call of the hawk species that inhabits their area, and then scream it out as they’re approaching a feeding station. At my parents’, they mimicked the Red-tailed Hawk; here, they do Red-shouldered Hawk. They’re pretty good mimics, and it’s usually enough to cause the birds already at the feeders to scatter, allowing the jays to have their pick of the food.

Blue Jay, Cyanocitta cristata

They’re also loud, vocal birds. Seeing a silent jay is much less common than seeing one that’s calling. In the fall and winter jays band together in loose groups, and their calls are partly used for communication between group members, keeping everyone together. Personally, I also think they just like to hear themselves talk. They have a wide variety of regular vocalizations, but their most common are the “jay” from when they take their name (although it could also be derived from an old German word, “gahi”, meaning “quick”), a “queedle-queedle” that sounds reminiscent of a squeaky closthesline, and various whistles.

Blue Jay, Cyanocitta cristata

And beyond even that, jays are gluttons. Or, at least, they get that reputation. Blue Jays have a pouch, or pocket, in their throats that they can tuck seeds in to, allowing them to pick up 10 to 15 at a time from a feeder. In the above photo this jay is throwing a seed back into one of the pouches. Usually when you see this behaviour it’s not because they’re greedy or especially hungry, but rather that they’re taking the seeds off to cache, or hide elsewhere. They use this behaviour to help ensure that they’ll have food to make it through the winter if heavy snows or prolonged weather prevents them from finding any at any time.

Blue Jay, Cyanocitta cristata

Jays aren’t the only birds that cache seeds from feeders, chickadees will also, and squirrels if they’re allowed to visit. In nature this behaviour would often apply to natural food sources such as acorns, and a single jay can cache up to 2000 to 4000 of them in a season. The jays only remember the locations of about 30% of their caches, using memorized landmarks to retrieve them, so inevitably some of the buried seeds will end up germinating. In the case of acorns, maples and other native species, this forgetfulness does the trees a favour in helping to get their seeds off to a good start.

Not all jays will cache seeds, depending partially on local food availability. The ones at my parents’ wouldn’t do it so much, but most of the ones here seem to. Or perhaps I’m just watching them more here. They’ll stuff their throat pouch till it’s bulging, and then take off to go hide them.

Blue Jay, Cyanocitta cristata

Although we tend to think of them as year-round residents, Blue Jays are actually a migratory species. Some will stick it out through the winter, but many hoof it south to more favourable climes, particularly in the most northern regions of their range. Blue Jays are found through virtually the entire east and Great Plains, and west through the Boreal forest, just nosing into northern BC. In the west their niche is filled by the Steller’s Jay (C. stelleri) a striking jay with an all-blue body and black head, and little blue (or white, depending on the subspecies) eyebrows. One of my favourite birds of my trips west have been these guys, both for their striking plumage and their character.

Migrating jays can be seen in flocks of anywhere from half a dozen to a few hundred. If you’re in a migrant-concentration area, such as a peninsula or a valley, you’ll often see jays flying high overhead in huge, silent groups in the fall. In a single morning in September it may be possible to see a few thousand go by overhead. These birds won’t go really far, just far enough for food to be easier to find come winter snow, a little like the juncos or some winter finches.

Blue Jay, Cyanocitta cristata

Although not a strict rule, larger birds generally live longer than smaller ones. Blue Jays have been recorded to live up to 18 years in captivity, though the chances of a wild bird even coming close to that age are fairly slim. Wild jays may live up to 6 years on average, usually succumbing to predation or weather pressures before they have a chance to experience old age. Various hawks, particularly the accipiters (Sharp-shinned, Cooper’s, and goshawk) are their main predators, being bird-specialists, extremely agile in woodland settings. The highest mortality rate occurs before the birds reach their first birthday, though, as they’re either helpless in the nest or still learning the ways of the world. This is why birds generally have such large clutches: most of the young won’t make it, even if they manage to raise them all to the point of leaving the nest.

Blue Jay, Cyanocitta cristata

Blue Jays are known for their bold behaviour. Falling in this category is mobbing. If you suddenly hear a big group of jays kicking up a fuss, shove your feet in your shoes and hurry out to see what it’s all about. Chances are there’s a hawk or an owl perched in a tree and the jays are expressing their displeasure, trying to encourage the bird to move on. Crows, weasels and foxes are also fair game, since they’re all potential predators of adults or their young. This mobbing behaviour is an adaptation that helps improve the survival of young (a predator that is driven off is one that isn’t eating your children). Although it seems like the adults are taking their life in their figurative hands, predators rarely try to attack them, usually because the birds are too quick for the predator to make a successful snap at one. Birds will usually mob in large groups, which also helps to protect individuals, since even if one was taken, the rest of the birds would continue dive-bombing the predator. I suspect mostly the predator just feels annoyed at being pinged on the head, and finds it easier to move on than try to catch one of these amazingly quick aggressors.

Blue Jay, Cyanocitta cristata

The jay, throat pouch full, crouches to take off for wherever he’s been hiding things. Jays really are very pretty birds, but overlooked because they’re so common. They’re entertaining to watch, even if they do go through our seed at an incredible rate, and they add a beautiful splash of blue to the feeder-scape. Hopefully as we get closer to winter they’ll get over their caching behaviour and just settle in to normal feeding (though they may carry on all winter).

A harbinger of spring

Edit: This post was recently included in the 70th edition of I and the Bird, a blog carnival focusing on, you guessed it, birds. You can check out the full edition at Earth, Wind & Water.

First starling of spring

The northeast got another dump of snow last night. Although it was only just lightly starting in the evening before I went to bed, by the time I got up there was a good eight inches on the ground, and it was still snowing with some conviction.

Snowfall

It finally began to taper off mid-morning. I happened to be at my parents’ for a few days of renovation work, so I didn’t have to go anywhere in it, but when my dad got home he said the driving was pretty slick on the way in to work. I helped my mom put the horses out in the fields; she normally takes them herself two at a time, but the younger two are very lively and with the slippery conditions she wasn’t keen about having a prancing horse at the end of each arm.

The feeders were very active this morning. Virtually every bird in the surrounding woods had come out to fuel up at the convenient food source while it was snowing. Surprisingly, I didn’t see the big flocks of redpolls that usually turn up in this weather; they seem to have traded off with American Tree Sparrows, which were unusually abundant.

First starling of spring

Mom and I were looking out the window at the activity when she commented, “what’s that dark thing in the tree, just a knot? Or is it a starling?” Sure enough, it was a starling. This is a very notable sighting for us (worth writing in my newly-started Nature Calendar!). Because my parents are out in the country, their starlings don’t stick around over the winter. They depart in the fall with the rest of the migrants, and then come back again early in the spring to nest in the eaves of the house and garage. There’re usually at least three pairs nesting here every summer.

First starling of spring

They’re the true harbinger of spring here. They arrive earlier than any other migrant, even the Red-winged Blackbirds, which are early arrivals. Unfortunately I don’t have a solid record of arrival dates over recent years. Shoulda been keeping a calendar… I’d be interested to know where they all go in the winter, whether they just skip down to the nearby town, or if they migrate some distance away.

Starling sneaking up on doves

I love starlings, they’re one of my favourite birds. This is due in part to my years in university, living in town, where during the winter they, and the House Sparrows, were the only signs of life for months. Their chattery song is very lively and upbeat, even when there’s a foot of snow on the ground. They’ve got lots of character, and I personally think their glossy irridescence is beautiful.

They aren’t so universally welcomed, however. Note these Mourning Doves are keeping an eye on this individual as she clambers around the tree foraging for edible bits. Starlings have a well-earned reputation as being bullies of the bird world. Although this one was alone, they usually move around in flocks in the winter, shooing other birds away from feeders when they move in to hoard all the food. They are definitely hogs when it comes to the good stuff, and has driven many a backyard bird feeder to “snob feeding” (to coin a Julie Zickefoose term). We don’t mind them here, however, since they’re so few in number.

Too close for comfort

The starling gets a little too close for comfort and the dove decides to move to a different perch. Starlings are also known for kicking more passive birds from nesting boxes. One of their main victims is the Purple Martin, but they’ll also kick out bluebirds, tree swallows, woodpeckers (including the hefty Northern Flicker), and just about any other bird that happens to have chosen a box the starling desires.

Starling and Blue Jay

Only the birds of similar size will challenge the starlings, as this Blue Jay prepares to do here. Blue Jays themselves are charismatic, bold and pushy, both with other birds…

Starling and Blue Jays

…and between themselves. The starling waits her turn.

I’m pretty sure this one’s a female. Starlings are neat because, although males and females have essentially the same plumage, during the winter and subsequent breeding season the “cere”, the soft fleshy part at the base of their bill, changes colour. Appropriately, the males turn blueish, and the females turn pinkish. Males also have nice, long, glossy throat feathers that they puff out and show off when singing. Incidentally, the white speckles you see on winter birds wear off over the winter so that the black, irridescent “summer plumage” is really just the same feathers they had all winter, minus the white tips.

Starling and cardinal

A female cardinal gives the suet a once-over. Cardinals rarely visit the suet, instead preferring the fat-rich sunflower seeds. A starling’s beak isn’t as well-designed to cracking open the hard shells of seeds, and their summer diet is primarily insects and berries. In the winter, the suet is their favourite. It’s not such a problem here, with just a few birds, but if you live in town and have a whole flock of them descend on your feeder, their powerful beaks can hack it apart and gobble it up amazingly quickly.

Their scientific name is Sturnus vulgaris. Back when the species was named, “vulgar” meant “common”, rather than ugly or unpleasant as it is often used now, so the scientific name basically meant “Common Starling”. I’m sure there are a lot of North American bird watchers who would also identify with the word’s other meaning, however.

Sunny day

Late morning the sun came out, and it was a beautifully bright day. Unfortunately, I didn’t find much time to enjoy it, working as I was.

I’m using my mom’s computer to post this evening. Most of my photos were a little underexposed because of the overcast, snowy conditions this morning, so I had to brighten them up a tad on the computer. Unfortunately, I do most of my photo editing in a different program at home, and I can’t seem to make Photoshop accomplish the same things, even though I appear to be using the same or similar command. So, because I was shooting through a window, some of these may seem a little cloudy, or the snow overexposed now; I just couldn’t seem to fix it, for some reason!

Winter bird irruptions

Common Redpoll

I have more to add to the winter colours theme of the last couple of posts, but feel like a change of pace today. I haven’t done any posts yet about birds, which is a little surprising given that birds are really my primary interest in nature (first birds, everything else second). So here’s a post on birds.

This winter, southern Ontario, and indeed most of northeastern North America, is enjoying a phenomenon called “irruption”. An irruption is similar to migration in birds, but takes place irregularly, usually every two to four years (depending on the species), rather than every year. Most irruptions are the result of food shortages in the areas where the birds usually spend their winters. Because the birds can’t find sufficient food there, they start to move south in large numbers. In many of these species, small numbers may be seen every winter, but an irruption is marked by a great abundance of the species south of its usual range. This winter seed crops, especially of deciduous trees, did very poorly in much of the north, resulting in low food availability for most seed-eating species.

The above photo is of a Common Redpoll, named for the red cap on its head, a regular irruptive species that usually comes south into southern Ontario and the northeastern states every couple of years. On their wintering grounds, redpolls feed primarily on the catkins of birch and alder trees. In a year of poor catkin production, redpolls will begin to move out of their regular range in search of an area with good food availability. In the south, this is often in the form of bird feeders. Redpolls love nyger seed (thistle seed), and will swarm nyger feeders in large numbers. They’re rarely seen in small numbers or individually, and flocks can reach 40 or 50, to upwards of 100 birds. This year is a bigger year for redpolls.

PISI1

Another frequently seen irruptive species is the Pine Siskin. This year they seem to have carried on through southern Ontario to places further south, but in some years they can be just as, or often more, numerous at the feeders than the redpolls. Siskins depend on evergreen cone seeds, but are also enthusiastic visitors to nyger seed feeders. Although they’re not very flashy, they can be distinguished from some other brown, streaky finches by their sharp, narrow beak (not well seen in this photo), and the yellow tints to their wing feathers.

Pine Grosbeaks and Bohemian Waxwings have also been reported in large numbers this winter. I haven’t had a chance to go out to look for either, yet, unfortunately. The last time I saw a Pine Grosbeak was some four or five years ago, and the only ones I’ve seen in Ontario were at the University of Guelph, back when I was a student there. They’ve been reported there again this year. That gives you an idea of the frequency of their irruptions this far south. I’ve never had the luck to see a Bohemian Waxwing, although I’ve gone looking for them.

RBNU4

These aren’t the only species that come south in years of low food availability. Red-breasted Nuthatches are seen periodically in larger numbers, and this year they moved out early in the fall, to destinations further south. My parents have one coming to their feeder this winter, however, and they’re usually gone by mid-fall. Black-capped Chickadees are usually year-round residents on their territories, but in years of good breeding success (that is, lots of babies!) coupled with poor winter food supply, large numbers of primarily young birds will move south looking for food. Chickadees moving through in the fall was slightly elevated this year, but 2005 was the biggest movement over the last few years. Blue Jays will also irrupt in larger numbers some years than others. We had a moderate movement this year, but the best year since I’ve been keeping track was probably 2003.

Northern Saw-whet Owl

Seed-eaters aren’t the only group of birds that undergo periodic irruptions. The seed shortages that cause birds to move also affect rodent populations in those areas, which depend heavily on seeds as their food source. In years of poor seed crops, rodent populations suffer sharp declines (often called “population crashes”). This year rodent populations had an especially severe crash, as last year’s seed crop had been good, encouraging a good breeding season this summer. That breeding success was followed by this fall’s seed shortage, causing a precipitous decline in numbers.

Birds that prey on rodents, such as owls, tend to follow their population cycles fairly closely. Because rodents were so abundant, owl populations, particularly the Northern Saw-whet Owl (pictured above), had a very successful breeding season. When rodent populations crashed this fall saw-whets began moving south in huge numbers. Saw-whets usually follow a four year cycle, where every fourth year their rodent prey, Red-backed Vole, peaks in number and so does their population. Saw-whets are naturally migratory and will move south every year, but the numbers encountered in the south vary according to the size of the movement. The combination of high saw-whet numbers due to this year’s breeding success and the low prey availability because of poor seed crops resulted in a larger-than-normal movement of saw-whets this fall.

GGOW

Great Gray Owls follow a similar pattern, although they usually only move as far as they need to to find food, which means they don’t often make it as far south as most human communities. A bird of northern Ontario, they often just move to another part of the north when prey shortages occur, since such shortages are often regional in nature, although small numbers are usually seen as far south as cottage country every winter. A few years ago, in the winter of 2004-5, a huge movement of these beautiful northern owls occurred in southern Ontario, and I had the opportunity to get out and see several. They’re the only ones I’ve seen.

Another species of owl that comes south every year, but can move in larger numbers some years, is Snowy Owl. There’s usually one bird that winters at Tommy Thompson Park (home of the research station, and as close to a backyard as I have here in the city) every year, although I haven’t seen reports of it this year. However, in years of larger movements, such as 2005-6, many Snowy Owls can be seen in a relatively small area (of suitable habitat, of course). The photo below was taken on Amherst Island, near Kingston, where we had up to 13 individuals during one day.

SNOW3