Searching for king rails is like looking for that needle in a haystack: the few remaining crow-sized birds are so well hidden in the marshes of southwestern Ontario, they are nearly impossible to detect
by Tim Tiner
Lurking deep within the most inaccessible marshlands in southern Ontario, the king rail is a secretive, solitary wading bird that blends into its densely vegetated surroundings. Seldom flying, flushing or swimming in open water, the mottled, rusty-hued, crow-sized bird is so reclusive that it was not even recorded in the annals of ornithology until John James Audubon noted it in 1835. Almost two centuries later, the bird remains a mystery, holding out in Canada largely in a few refuges in the most intensely farmed area of the province.
King rails primarily inhabit coastal marshes. Inland, they used to be concentrated around the wetlands of Lake St. Clair and the Ohio side of Lake Erie, as well as in the lower Mississippi area. It is believed that they were once more common in large marshes along this province’s Lake Erie and Lake Ontario shores. Today, however, more than 80 percent of southwestern Ontario’s original wetlands are gone. Only about a tenth of the once vast marshes in the Lake St. Clair area remains.
In 1985, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) estimated that Ontario had only enough suitable habitat left to support fewer than 300 pairs of king rails, and listed the bird as a species of special concern. By the early 1990s, fieldwork for the province’s first breeding bird atlas and the Rare Breeding Bird Program suggested that the actual provincial population of this species was between 20 and 52 pairs. In response, COSEWIC changed its status to endangered in April 1994.
Severe declines in the population have occurred elsewhere, too. The king rail has been declared endangered in most of the lower Great Lakes states, where only a small number still appear to nest. Outside of Florida and Louisiana, the bird is considered at least threatened.
The habitat requirements of the king rail are far more specific than those of the much more common and considerably smaller Virginia rail, says Jon McCracken, national programs director with Bird Studies Canada and a member to the National King Rail Recovery Team, formed in 1997. “King rails have a whole range of habitat needs that extend beyond the nesting period,” he notes. The plump, somewhat chicken-like birds require highly diverse environments, with grasses, sedges, cattails and other aquatic plants, shallow open water, exposed mud and drier shrubby or grassy hummocks. These rails build their nests on marshbound tussocks of grass just above the water, hiding the nests so well under canopies of bent stalks that none have been found in Ontario since the 1970s. After the large broods of downy black chicks hatch in early summer, their parents lead them to drier areas, such as shrubby swales.
Because rails are so difficult to spot, most records are of males calling as they stake out breeding territories after returning from the Atlantic and Gulf coasts in the U.S. around late April and early May. Typically in the early morning and evening, they utter a rapid series of harsh, resonant “kik-kik-kik” notes, rolling the last syllable.
The last province-wide surveys found 32 calling males in 1997 and 27 in 1999. More than half were detected on the Walpole Island First Nation, where a delta at the mouth of the St. Clair River forms nearly 80 square kilometres of marshes. Walpole Island’s mix of marshland grading into wet tallgrass prairie offers the ideal range of habitat for rails, as well as more than 50 other COSEWIC-designated species at risk. Smaller numbers of rails live in several other marshes along eastern Lake St. Clair, together covering almost 30 square kilometres. A few of these rails turn up elsewhere, mainly at large wetlands around Point Pelee, Long Point, Rondeau Provincial Park and Prince Edward County.
While rail numbers appear to have remained relatively stable in the past decade, McCracken says a further decline could go undetected. “It’s really difficult to provide a good estimate on what the population is doing in a given year,” he explains. “They’re a hard bird to study.”
“There are a lot of unanswered questions about their life system needs,” concurs P. Allen Woodliffe, another member of the recovery team, who is the Aylmer district ecologist for the Ontario Ministry of Natural Resources. “We have to use the best science to identify the habitat that needs to be protected.”
Earlier this decade, Woodliffe and his recovery-team colleagues completed a draft strategy proposing such research. Three years after the draft was due to be made public, however, it is still undergoing review. Barbara Slezak, a senior species-at-risk biologist at Environment Canada, the lead agency in developing the strategy, says that normally the process “can last from a few months to up to a year.”
Though wetland loss has slowed in southern Ontario, even large marshes used by rails may be affected by invasive species, such as choking monocultures of non-native phragmites and hybrid cattails. Pesticide and fertilizer runoff and other disturbances from encroaching development are also a concern. The largest concentration of rails, at Walpole Island and Lake St. Clair, is just downstream from Sarnia’s sprawling petrochemical plants.
The king rail’s food supply may also be threatened, notes McCracken, referring to reports that crayfish, the top food item for this bird, are now much less common in some areas than in the past. According to McCracken, research has shown that acid precipitation causes a decrease in calcium in aquatic habitats, which may affect crayfish.
Even though most of the known Ontario king rail population nests in parks, national wildlife areas and other wetlands protected from outright destruction, the survival of this species depends on safeguarding it south of the border. “The population in southern Ontario is on the extreme northern edge of its range, so we may never have had 200 pairs here,” says Dan Lebedyk, a conservation biologist with the Essex Region Conservation Authority. His organization manages Hillman Marsh, at the base of Point Pelee, where a male rail is detected about once every other year.
“The question is,” adds Lebedyk, “why is the local population not large and increasing? There really is no clear answer, other than that the population may always have been low.” McCracken agrees. The king rail in Ontario, he says, “is never going to get back into big numbers.”
Tim Tiner is the author of several nature guidebooks and a long-time contributor to ON Nature.