Kestrels Breeding in Burnaby

This past Sunday (July 16), following my own advice to “… get out there and take a look”, I was cycling east along North Fraser Way in Burnaby’s Big Bend area when an interesting bird silhouette caught my eye.

Kestrel silhouetted on a dead snag in the Big Bend area

Grabbing my bins from the bike pannier to get a better look, I was soon able to resolve the dark shape into that of a Kestrel. A “good” bird anywhere in the Lower Mainland, and a real and unexpected treat to see in Burnaby.

Grabbing my camera, I started a slow walk along Abbotsford Street toward the perched bird hoping for some good pictures, or at least a record shot of this Burnaby rarity, when I noticed a second Kestrel, this one sitting low down but half hidden in a thicket next to the tree in which the the first bird was perched. Two Kestrels! Wow!

Juvenile American Kestrel

Juvenile Kestrels are difficult to visually tell apart from their adult parents; however, this guy (yes, it’s a male), was making the occasional begging call, and when the adult male swooped down into the grassy road edge to catch some prey, and then flew up with it, junior was in hot pursuit for a meal.

So this was a recently fledged bird, which virtually guarantees it was hatched right here in the Big Bend area. In the 1 to 2 weeks immediately post-fledging, the young birds solicit food from their parents. After this period they cease begging as they become adept at capturing prey independently. So this young guy left the nest and took his first flights within the previous 2 weeks, and as a young, relatively weak flyer would not have travelled into the area from outside. It was Burnaby born and raised. Yay!

The Kestrel diet is primarily insects, especially grasshoppers, beetles, and dragonflies, and small rodents, especially voles and mice. All of the these prey items would be available in the area. The farming here is predominantly mixed vegetables, with some large areas of cranberry bogs to the north. The field edges are nicely unkempt, scruffy, and weedy providing lots of just the kinds of foods Kestrels need. Farming and wildlife can happily co-exist if the farming isn’t too industrialized and intensive.

Fields of vegetables with good Kestrel foraging habitat along its weedy edges in Burnaby’s Big Bend.

 

Fallow field of rough grass meadow full of insects, and small rodents – Kestrel food

I don’t know how much pesticide use there is on these farms, but the insect life was abundant when I visited. Perhaps this is a sign it is minimal, which is not only good for our health, but also that of the insect-eating Kestrels and other birds. Along the Byrne Road side of the area, the organic farm that was Urban Digs is now getting going again under new stewardship and name – Seed of Life Farm. No pesticide use there for sure. Another positive for the Kestrels.

So where would the nest itself likely have been? Kestrels are cavity nesters, using woodpecker-excavated and natural cavities in larger trees which are surrounded by large open areas for hunting food. We’ve got the open patches in Big Bend, but not so much the larger trees in the immediate area where I saw the birds.  However, there are many large black cottonwoods surrounding the fields, and Kestrels are known to use buildings too for nesting. A number of the old farm buildings in the area looked quite suitable to me.

Vegetable fields surrounded by the old farm buildings which may have provided a suitable Kestrel nest site

Both male and female Kestrels feed the young except for a short period after first hatching when the male provisions the female and the chicks on the nest. After 7-10 days both parents feed the young and this continues through the post-hatching period.

Breaking News (July18)

Went down to Big Bend again this morning to check up on the progress of the Kestrels. Despite the fact that somehow I had put a mostly un-charged battery in my camera and as a result missed all sorts of photo opportunities, it was a wonderful morning. The news is getting better.

There were at least 4 kestrels there this morning. Two adults, a male and female, and two juveniles, a male and female. Likely this represents the whole family, but given the birds were very active hunting and begging, I could have missed more family members. The young are still being fed by the parents, but are taking up perches and stances showing they are making the transition to feeding on their own. No more perching low down and tucked in like the juvenile I first observed Sunday.

The accepted common name for this species is American Kestrel. These ones, of course, are “Canadian” born and raised. In fact, I think we can safely claim this family group as “Burnaby” Kestrels.

Adult male “Burnaby” American Kestrel

If you head down to N Fraser Way and Abbotsford St. to see the happenings for yourself, please respect the farmland and private property, and stay on the roads. This area is not a public park.

 

 

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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.

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.

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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.