Purple Martin
This rareo species is increasing in numbers due to nest-box programs
Ministry of Environment, Lands and Parks peratures or heavy rain, for example, gramme at Maplewood Flats in North can mean the onset of nestling Vancouver. The total number of known mortality from starvation. This happens active martin nests in British Columbia because the low temperatures prevent in 1995 was 55. All but two pairs nested Why are Purple Martins insects from flying, with the result that on southern Vancouver Island. All at risk? parent birds cannot forage suc- were in artificial ever abundant in the province, cessfully. nest-boxes. British Columbia’s Purple Martin A natural consequence of “liv- The British The population now maintains a precarious toehold ing on the edge” is that the is currently ex- as a breeding species here. In the Columbia N number of martins tends to fluc- panding from a past, natural nesting sites were in tuate, sometimes dramatically, population of low of just a few snags near fresh or salt water, although since an event that claims even pairs in the early the majority of nesting records have has probably a few victims has a significant ef- 1980s. A nest-box always been from artificial sites. fect on such a small population. never program started Purple Martins adapted to changing Furthermore, population changes in the Cowichan circumstances numbered in Washington will likely Bay estuary at this by adopting spe- have a significant effect in more than a time probably res- cialised nesting By , all British Columbia: increases cued this species niches in har- few hundred known nesting there are likely to cause a from extirpation bour pilings, as spill-over in our province. birds. in British Colum- well as in crevices pairs in the The increased pressure put bia. There are now in buildings. province were on the species by loss of historic active Purple Martin sites on Vancouver However, even nest sites could conceivably com- Island at the Esquimalt Dockyards, the pilings are using artificial bine with such fluctuations to ex- Victoria Harbour, the Sooke Basin, the disappearing, nest-boxes, tirpate the Purple Martin from Cowichan estuary, Ladysmith Harbour, rotting away and British Columbia altogether. and the Nanaimo estuary; at Newcastle falling into the mainly erected Insecticides take their toll of Island Provincial Marine Park; and on water of the estu- on pilings. Purple Martins, particularly in the Lower Mainland at Maplewood Flats aries and bays their wintering areas in South and nearby Rocky Point. The present where they are found. Purple Martins no America. In a single incident in Brazil, population is still less than 75 pairs. All longer nest in buildings, either, having reported in 1989, 50 000 Purple Martins but one pair are using artificial boxes probably been ousted by introduced Eu- were killed. (that pair used an old Northern Flicker ropean Starlings and House Sparrows, hole in a piling). which compete for suitable cavities. What is their status? In recognition of its perilous status, Without human intervention, particu- he British Columbia population the Purple Martin was assigned to the larly the provision of artificial nest- of Purple Martins has probably British Columbia Red List. Red-listed boxes, this species would probably have never numbered more than a few wildlife species are candidates for desig- been lost to British Columbia some time T hundred birds. Their original nation as Endangered or Threatened ago. Indeed, by 1994, all known nesting distribution included the lower Fraser under the British Columbia Wildlife Act. pairs in the province were using artificial River lowlands, downtown Vancouver The Purple Martin is protected from nest-boxes, mainly erected on pilings. and the east side of Vancouver Island killing or collecting by provisions in the Purple Martins are at the northwest- from Campbell River to Victoria. The Wildlife Act and by the federal Migratory ern limit of their range in British decline of the species in the 1940s seems Bird Convention Act. Columbia. Their low numbers, together to have coincided with the establish- with the fact that conditions here are ment of the European Starling and with What do they look like? marginal for the species (this is usually the removal of old pilings from har- urple Martins (Progne subis) are the the case at the extremes of distribution), bours. By 1949, the species was breeding largest swallows in North America, means that they are particularly suscepti- only on Vancouver Island. Purple Mar- with a body length of about 17 to 20 ble to natural calamities. Just three days tins returned to the Lower Mainland in centimetres – about half as large ° P of cool (less than 6 ) maximum tem- 1994, in response to a nest-box pro- again as other swallows in the region. What makes them unique? he Purple Martin holds a special place in the history of wildlife con servation in North America. Long T reputed to be an efficient predator of insect pests, this large, dark swallow has for centuries been encouraged by native people in the American South- west, and later by wise farmers east of the Rockies, particularly in New Eng- land. Highly tolerant of human pres- ence, the eastern race of the Purple Martin readily accepts colonial nesting boxes provided for it. During the backlash against the ex- cessive use of insecticides precipitated by Rachel Carson’s “Silent Spring” in the 1960s, the Purple Martin’s prowess as a natural insect control agent im- pinged upon the national consciousness in the United States. “Two thousand mosquitoes a day!” (derived from a con- temporary estimate) was the battle-cry of the new conservation movement, and soon communities across the continent were installing nest-boxes by the score. Although these claims are now met with considerable scepticism, the mar- tin’s insect-eating habits are not in doubt. The Purple Martin still benefits from the legacy of its sixties popularity, to the extent that there are at present an estimated one million martin nest- boxes in North America. The benefit now works both ways: the Purple Mar- Adult males are an iridescent purple- Purple Martin’s wing is clearly visible. tin has become largely dependent on black. Females and immature birds There is also a superficial resemblance artificial nest-boxes, so our relationship are dark above and pale below. to the European with the bird is now a symbiotic one. Here in British Columbia, we are not Patches of black appear on imma- Purple Starling. Female ture males by mid-summer. Young martins could be likely to reap the full reputed benefits of males returning from their first mi- Martins are mistaken for other the Purple Martin’s prodigious appetite, as the western race nests in lower- gration are coloured like females, the largest species of swal- but with irregular splotches of dark lows, but are much density colonies than its eastern rela- purple-black. swallows in larger. Martins are tives. Furthermore, British Columbia represents the present northwestern Adult males could be confused North extremely vocal. with black swifts, which have Their distinctive edge of the Purple Martin’s range. We narrower wings. The bend of the America. calls make them can, however, have a significant positive swift’s wing is very close to the easy to locatewhen impact on the species in this province. body, giving its wings a sickle-shaped in flight, even at a considerable The Purple Martin is unique in one appearance, while the bend of the distance. other unusual way: it is the only single wildlife species to have a magazine (Purple Martin Update) devoted entirely to its welfare.
How do they reproduce? urple Martins are usually colonial breeders. The eastern race often nests in apartment-type nest-boxes, P while the western subspecies, although preferring to nest separately, often selects nest sites just a few metres distant from its neigbours. Adult males arrive back from migra- tion first, often returning to the previ- ous year’s nest sites. These males sing a special early morning “dawn song” while in flight high above their sites. This song attracts young males, which claim nearby nest sites. This behaviour is very beneficial to the older males; as the breeding season progresses, ones arrive back from migration. main in the nest into August or even they are able to mate with the females Colony size is very variable, from just September. In September martins flock that pair with the younger males, one pair to many dozens of pairs. The together before migrating to South increasing the largest colony currently active in America for the winter. While the larg- number of off- Martins British Columbia consists of un- est fall flocks recorded in British spring they can der 30 active nests. The female Columbia consist of only about 100 produce. They flock together alone incubates the eggs for 15 to birds, further south in the Seattle area, don’t have to before 19 days, although an incubation where the species is more common, help with rearing period of 21 days has been re- flocks of 14 000 have been recorded. them, as the migrating to ported in Victoria. Adult birds young males South America bring fresh leaves and cedar twigs What do they eat? raise them as into the nest cavity or box from bulletin from the US National their own. There for the winter. time to time. The purpose of this Museum probably best describes is also the ben- is not known; perhaps they help to the diet of the Purple Martin in this efit of ensuring that the colony is reduce nest parasites. The fact that wil- A elegantly redundant fashion: “The well-populated, so that the risk from low and cottonwood leaves – known for whole diet of the Purple Martin can be predators is diminished. It has been their insecticidal properties – are often fully covered by one word – insects! When found that the older males take the chosen helps to support this idea. that is said, all is said, for that is what the best and safest sites before the younger In British Columbia, birds can re- bird subsists upon and nothing else.” There have been no studies of the diet of Purple Martin in British Columbia, but all observations tend to confirm the above statement. Nesting martins appear to make extensive use of dragon- flies in feeding young in southern Brit- ish Columbia. Martins will forage many Nanaimo kilometres from the nest, often flying Present distribution of the Purple Martin high and calling loudly as they feed. For- Victoria Past distribution aging takes place from 30 to 200 of the Purple Martin metres above the ground. Where do they live? for maintenance. Pilings along he Purple Martin breeds docks and piers would be ideal across North America locations. Recent success- from southwestern British ful nest-box programs suggest T Columbia, across Alberta that up to five nest-boxes and central Saskatchewan per piling with a minimum of east to New Brunswick, and 25 boxes per site have the best south to Florida, southern chance of success for establish- Texas and the highlands of ment of a new colony. Permis- Mexico. The western race sion from and co-operation with breeds down the entire western marina owners and operators, seaboard and into Mexico, local boaters and yacht clubs while the eastern raceoccupies should be sought. the eastern half of the conti- In urban areas it may be neces- nent as far west as Alberta. sary to keep nest-box openings The species is absent from blocked until Purple Martins re- most of the dry western por- turn to avoid the problem of tions of the continent away House Sparrows and European from the coast. It is highly mi- Starlings using the boxes and gratory and winters in South out-competing the martins. In America, east of the Andes some areas martin house owners from Columbia to northern have had to control House Spar- Bolivia and southeastern row and starling numbers in or- Brazil. Wintering birds can der to maintain the martins. concentrate in large numbers, - To date, the commercially . one wintering roost site con- R. Wayne Campbell photo available “apartment-style” sisting of 5000 birds in Brazil. nest-boxes used in eastern North The exact winter range of the western What can we do? America have not been used by Purple subspecies is not known, although one he Purple Martin responds well to Martins in British Columbia. Gourd- banding record came from far southern nest-box programs. In Washington style martin houses have not been tested Brazil, at the southern edge of the win- and Oregon, volunteers have res- here. tering range of the eastern race. T cued the population from perilously The British Columbia Conservation The eastern race has been reported low numbers by using nest-boxes and Data Centre needs all information on a few times in extreme northeastern nesting gourds. In British Columbia, Purple Martin sightings, accompanied British Columbia. There are no records placing nest-boxes near to known colo- by as much information as possible. of breeding in the region, despite range nies should continue to increase num- maps in most field guides indicating bers locally. The addition of new boxes Please contact: that the species breeds in British Colum- in areas of historical distribution may BC Conservation Data Centre, bia’s Peace River area. However, nesting lead to recolonisation, as has been the BC Environment occurs nearby in Alberta, and naturalists case in North Vancouver. Individuals Ministry of Environment, are encouraged to watch for this species. and groups interested in helping Purple Lands and Parks Throughout much of its range, Martins in British Columbia are en- Parliament Buildings the Purple Martin will take up resi- couraged to build and erect nest-boxes Victoria, British Columbia V8V 1X4. dence wherever suitable habitat is along the waterfront on southern and present and nest-boxes are provided, eastern Vancouver Island and in People that put up nest-boxes are as long as the nest-boxes are not too the lower Mainland. Boxes should be encouraged to monitor the boxes for close to trees. In British Columbia, it constructed of cedar, and maintained Purple Martins and other species. Don’t almost always selects sites near or over regularly. A cedar nest-box should have forget to send a copy of your informa- open water. a life of about ten years. Locations tion to the British Columbia Conserva- should be chosen that allow easy access tion Data Centre! - . -. David F. Fraser photo David F. Fraser photo
. David F. Fraser photo
, : Wildlife Branch BC Environment Ministry of Environment, Lands and Parks Parliament Buildings Victoria, British Columbia V8V 1X4
--- . , Printed in British Columbia on recycled paper with vegetable base inks. ..