Purple Martins – First Confirmed Nesting in Burnaby

Back in September 2012 I wrote a blog post here on the pre-migration gathering of Purple Martins at Deer Lake Park.

In Martins Departin’? the birds involved in the “… noisy, energetic, and exuberant convocation in the tree tops along the boardwalk”  were almost certainly from the colonies at Maplewood Flats, North Vancouver, and at Rock Point, Port Moody. There were no breeding locations in Burnaby at that time.

Adult female and immature Purple Martins, August, 2012.

But now, almost five years later, I’m delighted to report that Purple Martins are actually breeding here in Burnaby, down at Burnaby Lake on the pilings at the west end of the rowing course. Not only is this a first modern-day record for the City (they likely did breed here historically), but there’s a special bonus involved here too.

The spectacular, province-wide recovery of Purple Martins, described in the earlier post, has been almost entirely due to the use of nestboxes erected by many dedicated volunteers here on the Mainland, and on Vancouver Island. Nearly all these locations have been over salt water, usually on wooden docks and pilings.

For some years now there has been great anticipation that, with the expanding population, martins will nest again over freshwater locations, which they historically did. Bingo! Burnaby Lake is freshwater, and the nesting here is one of only four very recent locations where nesting around freshwater has been confirmed – the others being in the mid-Fraser Valley.

How do we know they are nesting at Burnaby Lake? Well, head down to the Rowing Pavilion and take a look for yourself. With a little patience, every 10 to 15 minutes you’ll see the martins entering the upper-right nestbox on the fourth piling from the left. If all the numbers on the box were were readable, it would be 06 – 24. See the picture below.

Adult male Purple Martin exiting the occupied nestbox

A brief aside: this post is notable for its poor pictures. Unfortunately, the birds are distant, fast moving, and adding an additional murky quality today, was the smoke-filled air. Earlier pictures like the above are a little brighter. Today’s are, well, foggier.

Take your binoculars, and you’ll notice the returning adults are carrying food (mainly dragonflies and other large flying insects) into the nest. Try clicking once on the picture below for a larger view. Look carefully at the bird’s bill to see it’s stuffed with insects.

Male Purple Martin about to enter nestbox with food

Carrying food into the nest is one thing, but are there actually young birds inside? We can’t see them after all. However, a higher level of certainty is provided by the picture below. Here you can see the female departing the nest which a large white blob in her bill which she will very quickly drop into the lake. Like many birds, young Purple Martins’ poop is contained in a white mucous membrane “bag” which enables parents to keep the nest clean.

Female Purple Martin carrying fecal sac from nestbox confirming “someone” pooped inside.

Parents carrying out the fecal sacs suggests the youngsters are older than 8 days. After about 13 to 14 days, the young will defecate at the entrance to the nestbox from where parents carry off the fecal sac. I saw no evidence of fecal sacs at the nestbox entrance during my two visits. I estimate from these observations that the young are between about 10 and 14 days old.

Natural Hazards

After about 28 days the young should be ready to fledge i.e. take their first flight – always a risky time for all young birds as they learn the skills of flying and maneuvering, catching prey and avoiding predators.

An added hazard for these young martins is that there is at least one, and probably a pair of Merlins in the area, probably nesting too. I have seen one on both my visits. The parent martins are very vigilant however. Along with the Barn Swallows, which are quite numerous here, they instantly go into attack mode, calling loudly, and vigorously diving and swooping at the Merlin to drive it out of the area. The male seems to be more aggressive than the female in these interactions.

Distant shot of Merlin. The bird was aggressively chased from this perch by the adult male Purple Martin soon after this photo was taken.

However, Merlins, small falcons, are for their size, powerful bird predators. Often making their captures in mid-air after a high speed chase, they could be a significant threat to an inexperienced young martin taking one of its first flights.

A Long History Finally Rewarded

Joe Sadowski, a founding member of the Burnaby Lake Park Association, trail builder, and nestbox constructor extraordinaire, has been waiting 20 years, he tells me, for the Purple Martins to nest in the nestboxes he was instrumental in putting up at the lake. Along with the Park Association, Roy Teo, and Kiyoshi Takahashi have been monitoring these nest boxes and other Purple Martin nesting colonies for many years.

It’s a credit to all their hard work that we finally have these largest North American Swallows nesting in our midst. Rewarded indeed.

 

Martins departin’?

As August rolls into September, there’s lots of birdy action in the park, and a real feeling things are about to change. It’s a Janus time of year – looking back at summer, looking forward to fall.

Looking back: today I watched a Willow Flycatcher still feeding a newly-fledged youngster– a real summer sighting.

Looking forward, and a real pointer to fall, the Purple Martins are gathering in a noisy, energetic, and exuberant convocation in the tree tops along the boardwalk at the west end of Deer Lake signalling their intentions to soon head south. And pretty far south they go too. How about south-eastern Brazil? Incredible!

Here’s a group of three juveniles (upper), and what is likely an adult female (lowest bird), which were part of a gathering of more than thirty Purple Martins seen today (August 30th).

Purple Martins are North America’s largest member of the swallow family, and one of the largest swallows in the world. Compared to the more familiar Barn Swallow, you know, the ones that nest in the barns where many of us buy our veggies from the farms down on Marine Drive, they weigh-in at almost three times the size (56 g vs 19g). With a wingspan of almost 47 cm, that’s almost half a meter, this is a heck of a swallow.

And just like their smaller cousins, who classically line up along telephone wires and power lines prior to migration, Purple Martins gather in large groups too, made up of both adults and young, before they migrate. Here out west, they often gather in tree tops, particularly if  dead or bare branches are available for easy perching.

But, they’re not purple you’re saying! Well, the males are purplish – blue-black really. Unfortunately, they’re fairly tough to photograph, especially with the fairly basic gear I have, and the best I can do is some not-so-great pictures. Here’s an adult male, and if you squint hard, you may be able to convince yourself he’s… sort of purplish. (Don’t forget you can enlarge the pictures here by clicking on them)

Our western Purple Martins are a marvellous conservation success story. They are the comeback kids of coastal BC. By the early 1980’s the estimated BC population was in the order of ten breeding pairs only. That minuscule number was a clear signal we were about to lose them from the Province. In technical lingo, they were facing extirpation. We’d logged the old growth forests, removed snags, cleared burned areas, removed the old pilings from harbours and docks, and introduced House Sparrows and European Starlings. All of these factors led to the disappearance, or the occupation, in the case of the sparrows and starlings, of the woodpecker holes and crevices in pilings that the martins needed to nest.

Purple Martins are cavity nesters, and the solution to their decline was to provide them with artificial nest boxes over water. In 1986 a program of installing nest boxes on pilings in coastal areas was started by dedicated groups of volunteers, both here on the Mainland and on Vancouver Island. The first successes were on the east coast of the Island on the Cowichan Estuary.  In 1994, Maplewood Flats, just across Burrard Inlet from here, was the first successful re-nesting location on the Mainland. They hadn’t bred on the Mainland for probably more than thirty years. Kudos to the volunteers, and what a wonderful pay-off for everyone. We’re now enjoying the fruits of these efforts in Burnaby.

Our western martins are a little different from their eastern counterparts. They don’t use the classic condominium-style martin nest boxes that you would see in Ontario, Quebec, and the eastern U.S. Our birds nest in colonies too, but they are more loosely structured. They prefer individual nest boxes. Maplewood Flats in North Vancouver, and Rocky Point Park in Port Coquitlam are good places to see the nest boxes on pilings. We may have a few nesting here on the pilings at Barnet Marine Park. We’ll have to check it out next spring to see. I didn’t get down there this year to see what’s happening.

Since the conservation effort started 26 years ago the BC Purple Martin population has increased dramatically reaching 735 pairs in 2011. Isn’t it fantastic what a little TLC can achieve? In previous years, we’ve had over 100 birds in the park at this time of year. They should be here until mid-September, but their departure date and time varies from year to year. They’re Canadian birds, after all, and a bit unpredictable; kind of like our national airline.

So take a Deer Lake walk. You’ll hear the martins before you see them. Their beautiful, melodious warbles will cascade down from the air above. Along the boardwalk you’ll have a good chance to see them perched in the taller trees. They also like the big, old snag in the middle of the tall grass meadow near the bio-filtration pond.

Here’s a link to listen to Purple Martin vocalizations. Click here.

A full list of birds from my August 30th walk is here.

Postscript: the gathering of the martins was brief this year. They were all gone, left for points south, by September 5th. Weather conditions were just right I presume, and Brazil via Mexico was beckoning. The urge to migrate is is irresistable.