Purple Martin, The Conservation Area at Maplewood Flats Signature Species
by John Lowman
1) The Purple Martin (Progne subis)
With a length from bill to tail of eight inches and a sixteen inch wingspan, the Purple Martin is North America's largest swallow and the only martin. It breeds in North America during the summer months and spends its winters in South America in and around the Amazon Basin. There are three Purple Martin subspecies: Progne subis subis breeds in eastern North America and eastern Mexico; Progne subis hesperia breeds in Arizona, western Mexico, and Baja California; and Progne subis arboricola breeds along the Pacific coast of the US and Canada and parts of the Rockies, and is the race present at The Conservation Area.
In British Columbia the Purple Martin experienced a steep decline in numbers in the mid Twentieth Century. Competition from European Starlings and House Sparrows for nesting cavities close to water, the Purple Martin's favoured nesting site, is thought to be one of the main causes of the decline. By the 1970's there were only a handful of colonies on Eastern Vancouver Island left, the bird having disappeared entirely from the Lower Mainland. By the early 1980s, just five pairs of Purple Martin were recorded as nesting in British Columbia. As far as BC was concerned, the martin was on the brink of extinction.
To help restore the population, the Non-game section of BC Environment, funded by the Canadian Wildlife Service, Lynn Canyon Ecology Centre, and the Vancouver Natural History Society, initiated a nesting box program, beginning on Vancouver Island. Because of the success of the initial efforts, the occasional Purple Martin once again foraged in the skies over the Lower Mainland. In 1992 to help re-establish the mainland population, 120 nest boxes were installed at five marine intertidal zones where pilings were available to hang the boxes: Iona (Vancouver), Rocky Point (Port Moody), Maplewood (North Vancouver), Harris Road (Pitt Meadows), and Blackie Spit (Surrey). In 1994, Marshnotes (the quarterly publication of the British Columbia Waterfowl Society) reported that at least one pair of Purple Martins had nested at the Conservation Area at Maplewood Flats, the first to breed successfully in the Lower Mainland in 22 years.
In 1996 an independent banding team monitoring Purple Martins in BC found five active nests at the Conservation Area containing a total of 16 young. In early 2003, WBT became concerned about the failing condition of the original nest boxes and obtained permission from PortMetroVancouver to initiate the WBT Purple Martin Nestling Banding Program as a means of properly maintaining and better managing the colony. New boxes were introduced that year. Led by Master Bander Derek Matthews, the program continued until 2006, at which point it disbanded. In 2007, the contents of the nest boxes were examined to ascertain the number of breeding pairs. Early in 2008, WBT member June Ryder proposed the implementation of a foot patrol to monitor the colony, which led to the creation of the WBT Purple Martin Monitoring Program, which continues to this day. Under June's supervision as Program Coordinator, the observations are made by a two-person team using telescopes to record activity at each nesting box, including whether adults enter with food (Image 4 and 5) or exit carrying fecal sacs (Image 6) and any young peering out of the entrances (Image 7). These observations, carried out at least once a week during the latter part of the breeding season, allow the team to ascertain the number of nests.
The monitoring program revealed that, in the six years between 2007 and 2012, the colony averaged 55.5 breeding pairs annually, fluctuating between a low of 47 and high of 68. These data established that The Conservation Area at Maplewood Flats colony in each of those years was either the largest or second largest in the Georgia Basin. No wonder, then, that in 1996 WBT President Richard Beard mused in the very first edition of WBT's quarterly publication, WINGSPAN: "Of all the exciting developments in the first year of our existence, none surpassed the successful breeding of Purple Martins at Maplewood Flats, and we take it as the ultimate endorsement for having Maplewood Flats set aside for wildlife conservation."
The following photographs of the pilings, nesting boxes and Purple Martins could not provide a better confirmation of Richard's excitement, and a testament to The Conservation Area's success in fulfilling WBT's mandate "dedicated to wild birds and their habitats on the principle all wildlife must benefit."
Images 1 and 2 show one of the rows of Maplewood pilings. These are the "dolphins" from the log sort that occupied the mudflat up to the late 1970's on which the nest boxes hang. Image 3 shows Purple Martin in and around both old and new style boxes. The old boxes (the brown box third from the left and the green box second from the right) were screwed into the dolphin, which made it difficult to conduct an annual cleaning to get rid of nesting material which contains various parasites. The new boxes (those with numbers) are constructed to allow easy access to the nesting material inside, and are hooked onto a nail so that they can be quickly removed from the piling and stored during the winter.
The remaining images feature the Purple Martins themselves, and reveal the astonishing skill of an insectivore that catches almost all of its prey on the wing. Most of these photographs were taken when I accompanied WBT's Purple Martin Monitoring Teams (Colin Clasen, Derek Killby, Mark Habdas and June Ryder) as they observed the colony. The images of the martins in flight were taken as they approached the nest. They show the importance of large dragonflies in the Maplewood martin's diet, and for demonstrating why bird conservation relies so much on protecting their habitat. Without the creation of The Conservation Area's extensive freshwater pond system fed by water pumped from the aquifer below, there would be insufficient insects to sustain the colony, hence WBT's philosophy of protecting birds on the principle that all wildlife must benefit.
When wildlife benefits, so do we all.
Sources: "Return of the Purple Martin" Marshnotes Fall 1994 (article from information supplied by Tom Plath (Ministry of the Environment, and WBT member).
George F. Clulow, "Keeping Tabs on Maplewood's Purple Martin Colony" WINGSPAN Fall 1996 pp. 1-2.
WBT Co-Founder Patricia M. Banning-Lover provided other information about the history of the colony.
For information about the BC Purple Martin Stewardship and Recovery Program see http://www.georgiabasin.ca/puma.htm
For further information about the birds, see The Purple Martin Conservation Association (http://purplemartin.org/) and The Purple Martin Society, NA (http://www.purplemartins.com/).