July – Moult Month for Waterfowl

July is mid-summer for us humans, and the time of year when we head out to our parks and beaches. However, despite the attractions of the season, it’s just not as pleasant and pretty down at the Deer Lake beach as it usually is. In fact, things are looking downright scruffy and untidy.

All that feather shedding and goose pooping are making quite the mess. What’s going on?

For sure it’s the birds making the mess, and over one hundred Canada Geese can make a good one, but before getting ticked off, spare them a sympathetic thought. July is a pretty tough month to be a goose or a duck. They’re going through a big part of their annual moult. It’s biology and they have no choice.

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Not a pretty sight – moulting geese crowd Deer Lake beach

Walking around the beach, feathers are strewn everywhere and most of them are from the park’s ducks and geese.

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For all species of waterfowl (ducks, swans and geese), moulting is a pretty dramatic and stressful affair. Not only do they shed some of their body feathers, but also their wing feathers. And not just one by one; waterfowl lose their flight feathers all at once. Now if your flight feathers are gone, you’re flightless, and that can be serious – especially if you need to escape from a predator.

So our ducks and geese gather in areas where they have easy access to an escape route – in this case to the lake itself. The beaches at Deer Lake and Piper Spit at Burnaby Lake offer great locations for moulting birds.

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Canada Goose with all its flight feathers missing from moulting

Take a look at the goose above. The long, dark wing feathers that extend to the rear and partly cover the tail are completely missing and expose the black back and white rump that we see like this only at this time of year.

Here’s another bird, and here you can see the newly growing pin feathers, or blood feathers as they are also called. Over a period of a couple of weeks they will become fully developed and fully functioning wing feathers, or primaries. Right now they’re just tiny stubs.

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Note the emerging wing feathers encased in a blue, waxy coating on each side of the bird

The base of the pin feathers shown above are engorged with blood to aid their rapid growth. You can just see the new feather material emerging from the tip of the waxy coating. Damage to these pin feathers at this stage can be dangerous for the birds – it can lead to significant blood loss.

A little further along in the moulting process, here’s a bird with partially-grown new flight feathers that have not yet reached their full length.

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The dark-coloured, newly growing flight feathers (primaries) are best seen on the bird’s left wing. Note the still-to-be-moulted, old, paler, worn-looking, unshed flight feather on the extreme lower left.

As the flight feathers continue to grow they will once again cover the white rump and much of the tail. The bird above is also growing replacement tail feathers – note the uneven length at the tips. Growing so many large feathers at one time uses a lot of the birds’ energy, and they tend to loaf around to conserve it.

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Loafing on the beach, and then bathing in the lake. Remind you of anything?

Loafing on the beach enables the moulting birds to bathe frequently and preen those new feathers into good condition. This is important work; they will have to last until this time next year before being replaced.

Ducks also moult their flight feathers after breeding, but their transformation is even more dramatic. As they moult their wing feathers, they enter what is known as eclipse plumage. The males loose all their fancy body feathering, and often look much the same as females of the species. However, given they are flightless, it’s no doubt best to be as inconspicuous as possible. Plus the fancy, female-attracting plumage is no longer required now that breeding has just finished.

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This drake Mallard is losing his glossy green head feathers, rufous breast plumage and gray back and sides as he moves further into eclipse plumage

Here’s a picture taken earlier this year showing how much the drake Mallard transforms from eclipse to breeding plumage. Eclipse above, breeding below.

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Breeding plumage Mallard – the plumage we see most of the year

Ducks are very unusual in the bird world as the males have their two annual moults very close together in summer and fall. Most birds that take on different plumages for the breeding season have their second moult in the spring, ready for the breeding season.

Ducks in contrast, form pairs in the winter and males develop their pre-breeding finery during fall to be ready for winter pre-breeding pairing.

Lastly, here’s a very scruffy looking Gadwall at the lake.

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A very “female looking” drake Gadwall in eclipse plumage

Along with moulting waterfowl, many other birds  also undergo a moult at this time of year. Just like our ducks and geese, even our crows come down to the beach to make use of the fresh water from Buckingham Creek to bathe and condition their new feathers.

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Moulting crows gather around the mouth of Buckingham Creek

Unlike waterfowl, crows do not moult their flight feathers all at once, but lose and replace them serially over a period of several weeks. Such a moult strategy enables these birds to continue flying while undergoing this annual transformation. Looking up at crows flying overhead at this time of year you will notice the shape of the wings at the trailing edge is somewhat jagged, the result of new feathers growing in and others having been shed.

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Crow showing its moult in progress

The picture above is really illustrates what’s going on. This Northwestern Crow photographed last week at Deer Lake shows both body and wing feathers being replaced. The old, sun-bleached, brownish feathers contrast quite strikingly with the glossy, black new feathers just growing in. This bird has also lost feathers at the base of the bill, likely as a result of continually stuffing food into the mouths of its hungry young. All will be restored to glossy glory in a few weeks.

It’s enough to make you want to take a bath.

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Bathing Northwestern Crow, Buckingham Creek

While photographing the geese, ducks and crows shown above, I suddenly noticed feeding right along the edge of the Deer Lake beach were these two Long-billed Dowitchers – a rare treat at this location.

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Long-billed Dowitchers newly arrived from Northern breeding grounds

These two birds are adults in worn, breeding plumage. You’ll have to take my word on the “worn” part. Now these sandpipers have a different moulting strategy from the birds we’ve looked at so far. After breeding, the dowitchers migrate from the breeding grounds and then moult into their drabber winter plumage on the wintering grounds.

And many Long-billed Dowitchers spend the winter at Burnaby Lake. Here’s a picture from last winter. Look at the transformation. Breeding above, winter below.

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Long-billed Dowitchers in winter plumage

You can just see in the flanks of the bird below the first few hints of the greyer feathers of the winter plumage.

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Long-billed Dowitcher, Deer Lake beach

With all this shedding of feathers and growing of new ones it’s enough to make you want to scratch that itch. It’s that time of year.

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****

It’s been a busy spring of birding and travel that has kept me away from the blog. However, it’s back, at least for a while.

 

Northern Harriers – Update

Perhaps quite predictable, but good news nonetheless for the prospects for raising another generation of Northern Harriers at Deer Lake was the arrival on the breeding territory of a female harrier just a couple of days after the male was scouting out the lay of of the land.

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Female Northern Harrier newly arrived on her breeding territory.
Photo: Jason Hung

And of course we can anticipate the outcome of a male and a female on the breeding territory. The male was soon in courtship mode, and pursued the female whenever she landed on the meadow.

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Male harrier takes off in pursuit of female
Photo: Jason Hung

Copulation was not captured photographically, but here the male is approaching the female very closely.

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Harrier pair. Photo: Jason Hung

In the meantime I’ll keep you posted as events unfold. Even better, get down to the meadows and check out the action for yourself. However, please keep out of the meadows and observe from the trails. The birds’ breeding success depends on us, and our dogs not disturbing them.

I’ve also updated the photographs with higher resolution images on the previous post about the harriers at Deer Lake. Click here to view that post and the upgraded images.

Northern Harriers – A Sign of Spring

Not only is the calendar telling us that today (March 20th) is Spring Equinox, but nature too is showing us the seasons are changing. The first Tree Swallows of the year showed up at Burnaby Lake just over three weeks ago, and there are all sorts of signs of spring in our parks. From the blooming of the indian plum in the forests, to the peeping of tree frogs down at Burnaby Lake, all confirm what the birds are telling us – spring is here.

For me, one of the most exciting signs of spring is the return of the Northern Harriers to their nesting area in the meadows at the west end of Deer Lake. And just this past Friday (March 14) I saw the male harrier checking out his regular nesting area.

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Male Northern Harrier checking out its nesting territory prior to breeding

Not a great picture, but the bird was far out in the meadow. Below is a much better picture of the male harrier in flight. Jason Hung, who kindly let me use some of his photographs for this post (thank you, Jason), has much superior pictures of the birds than I can capture with my more basic camera gear. A lot of patience waiting for the birds to fly close-by is needed, and Jason’s patience and skill with a camera has certainly paid off. He’s managed to get some great shots over the past couple of years.

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Male Northern Harrier photographed at Deer Lake by Jason Hung

The fact that we’ve got harriers nesting at Deer Lake, is a real feather in the cap for Burnaby Parks – pun intended! We’re tremendously fortunate to have them nesting pretty much in the centre of the City because harriers need undisturbed wetlands or grasslands in which to nest and raise their young. Unlike many raptors, harriers nest on the ground, and as a result are very susceptible to disturbance from people and dogs. The Deer Lake birds arrived here about 10 years ago, and set up nesting territory in the park. As the park has got busier over the years with the increasing population around Metrotown, the pressure on the birds’ habitat has increased. At least once in the past few years, a dog killed a young harrier on the ground, but in most years the pair has successfully raised one or two young.

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This city sign is important protection for our ground-nesting Northern Harriers. Let’s watch and enjoy them from the nearby trails.

Now known as Northern Harriers, these birds were previously named Marsh Hawks and many readers may know them by the previous moniker. “Hawk” is a generic name applied to many raptors, but in the case of harriers it’s not a particularly apt descriptor.Compared to other North American raptors, harriers have a number of unique characteristics. Firstly, the males and females have strikingly different plumage; they are sexually dimorphic. As can be seen from the photos above, the males are grey backed, and mostly white underneath with black wingtips. The females, in contrast to the males, are mostly shades of brown above with buffy, streaked undersides.

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Female Northern Harrier. Photo: Jason Hung
Click to enlarge

Looking at the picture above, it’s possible to see that harriers have another interesting feature not found in other day-hunting raptors. They have facial disks like owls, which perform the same function for harriers as they do for the raptorial nightshift. They focus the sounds of prey to enable the capture of mice and voles, even when they may be out of sight in thick grasses over which the harrier is gliding.

Even more interesting, perhaps, is that the males are polygynous i.e. they mate with more than one female, sometimes up to five. However, mostly they are monogamous or bigamous, and in all cases the males provide most of the food for both females and the young. Our male at Deer Lake has typically had two females to provide food for. The second nest is in a virtually inaccessible part of the park, and while the patch of habitat is smaller, it may be more protected from intrusion because of its isolation.

The provisioning of food for female and young by the male gives us the opportunity to see a very exciting and dramatic event. When the male returns to the incubating female sitting on the nest, he gives a whistling call, which is the signal for the female to get airborne. Once she’s up and flying she also calls insistently. The male, flying higher, drops the prey for the female below to pursue and to catch in mid-air. It’s a wonderful aerobatic display.

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Male above, female below with prey just released by the male.
Photo Jason Hung

When the young are flying, the adults will drop in prey for the young to catch in mid-air. Below, Jason once again captured the action. This time it’s the female making the aerial exchange with one of her young.

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Female to young prey exchange. The in-transit food is probably a Townsend’s vole.
Photo: Jason Hung

The next couple of months will provide many opportunities to observe the comings and goings of the Northern Harriers at Deer Lake. Keep your distance, and enjoy the show. Nesting starts in earnest in the next couple of weeks. Spring is definitely here.

Our Dandiest Duck?

So let’s see: iridescent greens, blues, cobalt, purple, violet, bronze, ultramarine, crimson, burgundy spotted with white, black, and vermiculated gold; we could just as well be reading a list of exotic colours on an artist’s palette as descriptions of Wood Duck plumage – a dandy’s colours for sure. See for yourself; click on the image below.

WODU3pairWood Ducks frequently perch on logs, and tree limbs near the water

The females above are noticeably subdued in their plumage compared to the drakes, but being the sole incubator of the eggs, and the guardian of the young when they first emerge from the nest, it makes sense to be less eye-catching to predators. It’s all about remaining inconspicuous, and not drawing unwanted attention. This is a common evolutionary adaptation among many bird species, and among North American ducks nearly all species show this strong sexual dimorphism. Wood Ducks happen to be one of the species that push these male/female differences to the extreme. While it is the drakes that catch the eye on a first look, both females and males are worthy of close scrutiny that reveals the real complexity and subtlety of the colours of both sexes. Let’s start with a closer look at the females.

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Female Wood Duck – showing the diagnostic white eye-patch that tapers to the rear.

Most species of female ducks are relatively drab in colour, often a mixture of browns, buffs, and tans, but our Wood Duck above shows some iridescence both on the top of the head, and in the shoulder feathers (scapulars) spreading out below the neck. Taking an even closer look at the scapulars we see the subtle, but beautiful colours that we might otherwise miss when seeing a female perched alongside her fancier mate.

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Subtle but striking – the shoulder and some wing feathers of the female Wood Duck

Wood Ducks are unique among North American duck species. They are the sole representative on the continent of their genus, Aix (Greek for waterbird). In fact, the Aix genus contains only two species worldwide. The other is the Australasian Mandarin Duck – another contestant in the “dandy duck” stakes. Both are part of a larger group called the perching ducks. Wood Ducks certainly live up to that classification. They are often seen perching along the water’s edge on logs and in sometimes in trees.

Confirming their scientific classification as perching ducks, Wood Ducks line a tree limb over Eagle Creek

Confirming their scientific classification as perching ducks, Wood Ducks line a tree limb over Eagle Creek, loafing, preening and snoozing.

There’s a certain irony, however, to the dramatic sexual dimorphism we see in Wood Ducks. It’s the drabber females’ choice of mates that drives the evolution of the spectacular male plumage. Pairs are seasonally monogamous, i.e. they pair-up anew each year,  but because the males play no part in rearing the young (more “dandy” behaviour?) their breeding success is more strongly determined by their ability to attract a mate. Therefore, the bolder the plumage, which indicates to the female readiness and suitability of the male for breeding, the more chance the male has of being selected and passing on his genes to the next generation. Other species of birds in which the males do assist with rearing the young are frequently less sexually dimorphic. Here’s the drake Wood Duck.

Wood Duck male – Dandy indeed!

Wood Duck male – Dandy indeed!

The colours above need no more description, but it is worth noticing the rakish crest that flows down the back of the head. The female has one too, and among the dabbling ducks in North America (Mallards, wigeons, and teals etc), the crest sported by the Wood Duck is unique.

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This drake is perched next to a female, and is lifting his head to display to her the “full effect”.

The gradations of colours here on the head are quite striking in close-up. No doubt they’re just what an interested female is looking for.

Paired Wood Ducks

Paired Wood Ducks

And while all this fantastic plumage is in pursuit of one thing – passing on the male’s genes to the next generation, Wood Ducks also need suitable habitat to breed successfully – marshy lakes and ponds with lots of surrounding vegetation. Oh yes, and one more thing; they need nest cavities. Before the forests of North America were extensively cleared, and the old trees that contained natural cavities from broken branches and abandoned woodpecker holes were cut down, Wood Ducks were numerous. However, by the late nineteenth century there were real fears that the Wood Duck would go extinct from the combination of habitat loss and over-hunting. After the Migratory Bird Act of 1918 ended the legal hunting of Wood Ducks, the species recovered rapidly. Concerned conservationists also helped them along by providing nest boxes to replace the natural cavities that had been lost in forest clearing.

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Wood Duck nestbox – Piper Spit, Burnaby Lake

The best place locally to see lots of Wood Ducks is Burnaby Lake at Piper Spit, and it’s no coincidence that at this location you’ll also see many nest boxes put up specifically for Wood Ducks. Although there are many nestboxes at Burnaby Lake, there may not be enough for all the ducks needing one. There are frequent incidents of egg-dumping here when more than one female lays her eggs in a single nest box – up to thirty eggs in a one box. Now not all the eggs will hatch in these conditions, but for a female that can’t find a nest cavity of her own, it seems a good strategy to ensure that at least some eggs produced by the female will hatch.

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Glaucous Gull – A Rare Deer Lake Visitor

There is always a small flock of gulls that spend the winter on the beach around the children’s playground at the east end of Deer Lake, but this year more than the usual number has shown up, and they’ve been joined by a rare visitor from the Arctic.

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Gulls winging into the beach at Deer Lake

The birds come and go over the course of the day, but at times this month I’ve counted up to 300 on the beach and out on the lake – a good number.

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Adults and immature (the brownish ones) gulls on Deer Lake beach.

They come to the beach for a couple of reasons: one, they like to bathe and clean up their plumage at the mouth of Buckingham Creek where it flows into the lake over a gravelly bar. And two, because people come down to the lake to feed the ducks, often with the kids in tow, the gulls hang around to grab their share of the handouts. Of course it’s against park rules to feed the wildlife, but the happy result for us is that the gulls get quite used to people, and it gives us the chance to see them up-close and personal. And to identify gulls, good close looks are preferred.

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Spot the visitor?

If you take a close look at the flock, you’re likely able to pick out the one that is a little larger than the others, and looks a little different too. There are other brownish gulls on the beach, but the washed-out looking bird in the centre of the picture above is the Glaucous Gull, our rare visitor from the Arctic.

Here’s a close up.

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Glaucous Gull – Deer Lake beach

So what makes this one different? Isn’t it just another gull? Firstly, it’s large, and it’s by far the palest looking immature bird on the beach. There are other brownish birds, but this bird is basically a dirty-white overall with light brown markings on the back and wings. Its wingtips are virtually white. It has a large, heavy bill which is quite strikingly bi-coloured, pink at the base, and black-tipped.

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Bi-coloured pink and black bill, dark eye, and dirty white plumage are key features that identify this immature Glaucous Gull.

When Glaucous Gulls do show up in British Columbia it’s mostly as single birds. They are usually in their first or second winter of life, and our visitor fits this general pattern. The Deer Lake gull is a first winter bird. Glaucous gulls are among a number of large white-headed gulls that take four years to reach adulthood, and acquire their full adult plumage. This one has three more years to go.

The bird below is also a white-headed gull, but it’s quite a bit smaller than the Glaucous Gull, and takes three years to reach adulthood.

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Ring-billed Gull adult

I think the Ring-billed Gull is quite a nattily handsome bird and is the species most frequently seen down at the lake, and fortunately is also very easy to identify in adult plumage. The combination of grey back, black wingtips with white “mirrors”, yellow legs, yellow eyes, and a bold black ring on a yellow bill is diagnostic. This one is still in winter plumage shown by the dusky flecking over the head and neck. These brown feather tips will wear away over the course of the winter to leave a pure white head ready for the breeding season.

Gulls are difficult group of birds to identify, and I usually recommend for casual or beginning birders to leave them until later. Start with easy stuff. However, some birders get  “into” gulls in a big way; they get captured by the complexity of identification and the excitement of finding the rarities among the commonplace. However, it’s a challenge. The birds have different plumages in each year before they reach adulthood, with the immature birds being the most challenging to sort out.

As adults, most gulls show a combination of white head, neck and body, grey back or mantle, and dark wingtips with white “mirrors”. Many of the differences among species are subtle. And to cap it off, gulls of different species frequently interbreed, producing all sorts of hybrids with features of two different parents making identification even more difficult. There are lots of hybrid gulls in the Deer Lake flock. Here’s just one example below.

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Probable Glaucous-winged X Herring Gull hybrid

I could go on and on about gulls, but I fear my audience will soon be mimicking the yawn of the Glaucous Gull below.

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Glaucous Gull centre and Glaucous-winged Gull to the left front

However, one final suggestion for a common and easy-to-identify gull is the Glaucous-winged Gull shown on the left above. It’s a large gull, yellow billed, pink legged, and with a pale grey back and grey (not dark or black) wingtips with white mirrors. If the grey coloured wingtips match the colour of the back, you’ve got a Glaucous-winged Gull.

Glaucous, by the way, refers to the grey colour of the adult birds’ back, and wings. Adult Glaucous Gulls have white wing tips.

Gull numbers at the lake will drop steadily from now on. The Glaucous Gull will likely head back north, perhaps to Alaska. It won’t breed for another three years, and when it does, it will do so on Arctic breeding grounds. The Ring-billed Gull will head back to its breeding grounds that stretch across central BC, the Prairies and all the way across the country to Newfoundland and Labrador. The Glaucous-winged Gull breeds here on the BC coast, in Washington State, and right up to Alaska and the Aleutian Islands. It is our commonest year-round gull in Metro Vancouver and the Georgia Basin.

So you’ve hung in this far, thank you for your persistence. Gulls are not everyone’s idea of a fun topic. I’ve not posted for a while, but life just gets really busy sometimes. I plan to be posting more regularly as we head into spring. There’s lots to see and enjoy in our parks. Next up are Wood Ducks, our dandiest ducks.

A Blue Jay – the real thing!

Around these parts, many people name our local resident jays, blue jays. Birders like me feel a mild, internal cringe at this minor misnaming, but we usually let it pass without comment. After all, our birds are blue, and they’re definitely jays. The fairly common blue jay of our coastal forests is of course BC’s Provincial bird, the Steller’s Jay. Loud, brash, and with lots of attitude, it fits in well out here on the “left” coast.

Its somewhat shyer Eastern cousin is the real Blue Jay, and we’re incredibly lucky right now to have one visiting a backyard feeder regularly on North Gamma Ave, in North Burnaby.

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The real Blue Jay is a very rare visitor to the West Coast.

Common east of the Rocky Mountains and right across southern Canada, Blue Jays are rare visitors to the Lower Mainland, and as far as I’m aware this is the first one we know to visit Burnaby. It’s certainly a new addition to my list of Burnaby birds. Although rare in our region, Blue Jays are expanding their range in BC west of the Rockies. In fact, there is a second Blue Jay in south Vancouver right now. Two Blue Jays in one winter in this region is exceptional.

But let’s enjoy our bird. Compared to its cousin (shown below), the much more familiar Steller’s Jay, the Blue Jay’s blue is a lot paler, and the bird is much more boldly marked. Very similar in shape, size and structure, both birds are attracted to bird feeders and have a particular fondness for nuts of all kinds. Both members of the Cyanocitta genus, they are closely related, and where the two species are found together, they sometimes hybridize.

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Steller’s Jay, BC’s Provincial Bird

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Blue Jays sport many more colours than our resident Steller’s Jays. Various shades of blue make a showy contrast to areas of black, white, gray and taup – a handsome bird!

While both these birds show quite different shades or colours of blue, their blues have a fascinating connection. For the most part, wherever blue bird feathers are found, including our two jays here, it is not the result of pigmentation. In other words, the feathers are not coloured blue in the way blue jeans are, or blue cars are. At the microscopic level, their feathers have specialized structures that scatter the incoming light to produce the very precise blue colours we see. This is called structural colour. If you found a blue feather from one of these birds and held it up for the light to shine through it, it would look brownish. Here’s to structural colour – our two jays would be a lot drabber without it.

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Dark blues and black predominate in the Steller’s Jays’ plumage.

So, if you’re heading up to North Gamma to look for the bird, focus your efforts north of Cambridge Street. A good clue will be other birders and photographers standing around waiting for the bird to put in an appearance. Another clue to the bird’s presence is its distinctive call. Listen out for it, as this bird frequently announces its arrival before putting in an appearance. And please be respectful of people’s homes and privacy.

They’re Back!

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Three of five chum salmon spawning in Buckingham Creek this morning (Nov 6th).

After last year’s salmon surprise at Deer Lake, the chum salmon are back again this year attracting the curious, bringing smiles to people’s faces, and causing gasps of excitement. “They’re Back!” Not the return of last year’s fish, of course, but a new run of chum salmon has surged up Buckingham Creek at the east end of Deer Lake, almost to the day they appeared last year.

The fish are actively flushing the accumulated silt from their redd (spawning bed) and getting on with the business of producing the next generation.

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Vigorous body undulations, and splashy tail action cleans out the redd ready to receive the chum salmon eggs.

After a fantastic journey to and from the Pacific Ocean where they arrived as smolts, and spent from 3 to 5 years growing to maturity, these fish are returning to spawn in this tiny urban waterway. Last year’s post gave more detail about the journey these fish have made to return here to spawn.

Periods of rest separate periods of vigorous activity, perhaps not such a surprise after such a long journey. But spawning is a strong urge and the salmon give their all in the final act of reproduction. In a couple of weeks, we’ll see their spent carcasses in the creek.

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After some energetic gravel cleaning, the fish rest awhile before continuing their spawning.

Don’t miss out. Welcome back our urban salmon. The action won’t last for long.

Halloween Nightmare – for a snail!

It’s All Hallow’s Eve. Gore-spattered ghosts, ghouls, and goblins roam our streets in packs.  Vacant eye-sockets glare at us from dark doorways, and dripping bushes. Blood curdling wails of pain and screams of fear echo through the neighbourhoods.

Putting the frighteners on ourselves is all part of the fun, and the scary stuff is not that nightmarish when we know that once all ‘tributes’ have been collected, a warm home awaits us with hot chocolate and a feast of goodies.

However, from our comfy seats at home, can we give a thought for the lowly snail? If snails could think like we do (they don’t) surely their Halloween Nightmare would be one that would terrify us too – trapped, unable to move, and being eaten alive, head first, Hannibal Lecter style.

And that’s what’s happening below; not in the movies, and not in our imaginations, but for real.

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Calosoma ground beetle eating a snail.
Click to enlarge.

With the beetle’s mandibles plunged into the opening of the snail’s shell, the hapless gastropod is being eaten alive, head first. I witnessed the dramatic scene above while gardening this week .

Ground beetles, like the one above, are quite common carnivorous denizens of our gardens. Often unseen because of their nocturnal habits, we frequently disturb them while digging around in our gardens. Far less frequently do we see them with their prey.

However, it’s a good reminder that many of the invertebrates in our gardens are actually doing us favour, although I’m sure the snail wouldn’t see it that way. In this case our friendly beetle is consuming a garden-plant-eating snail. Remember: Don’t squash the insects, and do avoid the pesticides!

The two hard “shields” covering the back of the beetle and protecting the wings underneath are called the elytra. They are nicely striated in the above specimen, and suggest that it’s in the Calosoma genus. As I’m a bird man, and less of a bug man, my identification of the beetle is provisional.

And while I’m on the topic of ground beetles, I thought I would take the opportunity to share a picture of another striking member of this large family of insects. I managed to photograph this beauty last year in my garden after a brief shower left it with a shiny coating of water over its smooth, red elytra. Again, my identification is provisional. I believe this one is a member of the Carabus genus.

Both beetles are in the 25 to 30 mm size range.

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Carabus ground beetle after a rain shower.
Click to enlarge

Take a close look at the beetle above and you’ll notice it’s missing part of its left front leg, and part of its right antenna.  It’s an eat-and-be-eaten world all around us. So if snails could have Halloween nightmares, then I’m certain that ground beetles would have theirs too. Who can imagine what frightening beasts could attack and dismember ground beetles?

Happy? Halloween.

Alien Invader Arrives in Burnaby – finally!

The Eurasian Collared-Dove’s invasion of North America is a remarkable story. This dainty member of the pigeon and dove family has found human-altered landscapes to be just what it needs to breed rapidly, and spread like an avian tsunami across the continent from east to west. The bird’s arrival here in Burnaby may be one of the final chapters in its conquest of the whole continent, and in particular here on the West Coast. The surprise for me is that it has taken so long to arrive in our fair city.

Eurasian Collared-dove

Eurasian Collared-dove. Since the bird’s introduction to the Bahamas in the 1970′s, its population has exploded and it has spread right across the continent.

For more than six years now, Eurasian Collared-Doves have firmly established themselves in Surrey, Delta, Ladner, Richmond, and up the Fraser Valley. Even though I have been watching out for them, to my knowledge they’ve only just arrived in Burnaby this summer.

Despite my expectation to find the bird here in Burnaby, it was readers of this blog who were the first to notice the alien species in our midst. Back in late July Brian Johnson sent me a couple of pictures of a “mystery” bird he was seeing and hearing in his yard. Bingo! Brian’s distant pictures provided the first evidence I had seen of Collared-Doves in Burnaby. Next up was a phone call a week or so later from Tony Fabian. “Hey George, I’ve got this odd-looking pigeon in my yard. I can’t find it in any of my bird books.”

It took me a couple of weeks more to actually see the birds for myself, and take some pictures that I could publish here. The birds have proved to be skittish, and difficult to get close-up photographs. Finally, my friend Ross McIlroy invited me around to his backyard where the doves were a new arrival at his bird feeder. Although I didn’t manage to get the hoped-for closeup, one of the birds was conveniently perched nearby.

Eurasian Collared-dove

Favouring backyards and back lanes, Eurasian Collared-Doves frequently perch on power lines.

A frequent concern with introduced species, especially highly invasive ones like the Collared-Dove, is their negative impacts on our native species with which they compete for food, territory, and nest sites. So far, Collared-Doves seem to be living harmoniously in North America without significant impacts on our native North American doves and pigeons.

A case in point is its seemingly benign relations with my favourite local member of this family of birds, the Band-tailed Pigeon. It’s good to know this beautiful bird is apparently unaffected by this alien invader. Band-tailed Pigeons breed sparsely in forested areas scattered across our city, but they often show up in large numbers during Fall migration. Their favoured food at this time of year is acorns, which they swallow (whole!) to fuel their migration to points south.

BTPI#1

Band-tailed Pigeons have bright yellow legs, feet and bill, and beautiful, vinaceous body plumage. Click image to expand the image – this is a spectacular bird.

So what’s the difference between these two species – one native and one alien invader? Interestingly both have prominent neck collars and contrastingly patterned tails.

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The dark and light tail bands give the Band-tailed Pigeon its name – nice feeder bird, Ross!

The prominent white collar on the Band-tailed Pigeon above, contrasts with the prominent black collar of the Collared-Dove below.

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Dark collar, pale pastel overall, and dainty appearance characterize the Eurasian Collared-Dove.

So the aliens are now in our midst, and fortunately they are neither to be feared nor shunned. With some careful observation they are easily identified, especially if you are lucky enough to have them coming to a bird feeder in your garden.

Neither species should be confused with the familiar feral pigeon commonly seen along railroad tracks and in parks. That bird is the introduced Rock Pigeon, and that’s a story for another time.

To hear the cooing song of the Eurasian Collared-Dove click here, and then click on the play button.

Cooper’s Hawks

Cooper’s Hawks are likely the commonest raptor found in Burnaby, but much of the time you wouldn’t know it. Like all members of the accipiter family (true hawks) they are specialized, bird hunting, ambush predators, that mostly remain hidden deep in cover from where they launch surprise attacks, and pursue their avian prey through the woods.

However, in July and early August when the young birds have just fledged (left the nest), they frequently perch out in the open for a few days, noisily begging for food. Recently, friends in North Burnaby phoned to tell me that they and their neighbours were being entertained by a family of four recently-fledged, and two adult Cooper’s Hawks in nearby Montrose Park.

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Three of four juvenile Cooper’s Hawks await their parents’ return with food – Montrose Park.

When I headed over there the next day, the birds seemed to have learned their first lesson as young raptors – stay hidden. No doubt the youngsters had been mobbed by smaller birds, and the neighbourhood crows, which will attempt to drive all raptors from their territory. But, while staying hidden, they were still calling loudly for food. After a bit of searching, and using their long, wheezing whistles to guide us, we finally managed to find a couple of the young birds perched, and begging for food in the deciduous trees along the Trans-Canada Trail through Montrose Park.

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Juvenile Cooper’s Hawk concealed in big-leaf maple, begging for food

The adults were not  around when we were there, and were likely out hunting for the young birds’ next meals. Over the next two or three weeks the young will continue to be fed by their parents, but they will increasingly be left to their own devices until, and after four or five weeks, they will be abandoned to their make their own way in the world. If they haven’t honed their hunting skills sufficiently in the meantime, they’ll not survive. They may still hang around in the area of their birth up to six weeks after fledging. You should have a good chance of finding one if you head down to Montrose.

It’s a steep learning curve for the young Cooper’s Hawks to become independent hunters, but they’re born with all the equipment they need. Their incredibly sharp vision puts human  eyesight into the piker division. Cooper’s Hawks can not only resolve much greater detail at greater distances than humans, but they are also able the track the rapid movements of their prey through the forests, which for us would simply be a blur. Their binocular vision gives them the very precise judgement of distances which is essential for capturing fast-moving prey.

COHA#6

Forward facing eyes give Cooper’s Hawks a wide field of binocular vision, essential for hunting.

Cooper’s Hawks wings are relatively short and rounded, whereas their tails are relatively long. You can see in the picture above the long extension of the tail beyond the wing-tips. This combination makes them stunningly maneuverable in flight. Fast to accelerate, they are able to make incredibly sharp turns at very high speeds to pursue their prey through dense vegetation. And they often seem totally fearless when chasing down their quarry.  I recall watching one chase a starling from a bird feeder, and then crash full force into a dense shrub, into which the starling had plunged to make its escape, only to yank it out, clutched in one foot.

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Long, sharp talons make for a deadly grip on the Cooper’s Hawk’s prey

Cooper’s Hawks are a success story in the urban bird world. Once in serious decline across North America due to hunting, pesticide contamination, and loss of forest habitats, they have now rebounded and adapted extremely well to urban environments, including our parks, where they find plenty of prey.

Andy Stewart in Victoria has had a long term program of banding and monitoring Cooper’s Hawks in the capital city, and he has discovered some of the highest densities ever recorded on the continent just across the Straight from us. I would not be surprised at all if we have comparable population densities of these beautiful predators right here in Burnaby.

Hawks banded in Victoria have been recorded a number of times on this side of the Strait of Georgia. Keep an eye out around your bird feeders this winter. Cooper’s Hawks often snatch their prey from our gardens.

To read more about Andy’s work, click here. A longer article, with a more continental perspective on Cooper’s Hawks can be found here.