From the COSEWIC report (direct quotes):
- Yellow Rails have such a narrow tolerance of water levels for breeding that any given location may be suitable in one year but not the next, especially in prairie regions, where the species mainly occurs in seasonal wetlands (Prescott et al. 2003).
- An occupied marsh in southern Manitoba was partly destroyed for highway development (Wilson 2005), and between the 1960s and 1980s 10–50% of township sections in that region lost wetlands (Oswald 2000). Wetlands in southern Ontario and Quebec are under heavy pressure from various forms of fragmentation and degradation. Over 50% of potential Yellow Rail habitat along the St. Lawrence and Saguenay Rivers was lost during the last decades of the previous century to filling and construction projects, such as harbour infrastructure and highways (Robert et al. 1995; Alvo and Robert 1999). The invasive non–native form of Common Reed, Phragmites australis, has infiltrated rail habitat at Île aux Grues during the last 15 years (Marineau et al.2002; Dalpé–Charron 2006; Rivard 2007), and active management is needed to halt succession at Lac Saint–François National Wildlife Area (Brisson et al. 2006).
- In the rest of the range west of Quebec, the bird’s distribution is so scattered and poorly known that only a rough guess can be made from inventories of wetland protection in general, which estimate that less than 10% of wetlands are protected there (Wiken et al. 2004). About half of the sites in Quebec are protected, mainly as National Wildlife Areas (Robert et al. 1995). In New Brunswick, the bird’s distribution is too poorly known to estimate how much is protected, although the sites where the bird has been found most reliably are protected as National Wildlife Areas (Portobello Creek and Tintamarre National Wildlife Areas) or as Class II Protected Natural Area (Grand Lake Meadows), which prohibits, for example, most commercial or industrial development. Altogether, less than 10–20% of known Yellow Rail habitat is in protected areas. Much of the remaining habitat is partly protected by various federal, provincial, and municipal policies and regulations concerning development on wetlands (reviewed in Rubec and Hanson 2008). However, many sites may not be large enough and/or sufficiently typical of wetlands to receive such protection.
- Nonetheless, in the US, it is clear that the species has disappeared from the former southern edge of its range, specifically southern Wisconsin (Grimm 1991), northern Illinois, and central Ohio (Alvo and Robert 1999).
- Habitat loss and degradation continues locally not only through drainage, dyking, infilling, and diversion of wetlands, but also through converting rail habitat for other uses. Specific recent examples include several historically occupied sites in Alberta that have been co–opted for grazing (Prescott et al. 2003), areas of Douglas Marsh in Manitoba that were proposed (albeit rejected) for highway development (Wilson 2005), and various commercial and industrial developments along the St. Lawrence River in Quebec (Dalpé–Charron 2006). Energy projects in Alberta and Northwest Territories threaten habitat both through direct habitat destruction, for mines, pipelines and hydro lines, for example, and indirectly through changes in hydrological regimes, particularly for oil sands extraction (Alvo and Robert 1999; Oil Sands Wetlands Working Group 2000; Goldrup 2008). All–terrain vehicles have also been identified as having the potential to disrupt wetland habitat and to disturb wetland birds (NBDNR2008).