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.