Summer habitat of yellow rails, Coturnicops noveboracensis, along the St. Lawrence River, Quebec

Abstract

As part of our investigations of Quebec birds at risk, we studied Yellow Rail (Coturnicops noveboracensis) habitats at three localities (Ile aux Grues, Cacouna and Lake Saint-François National Wildlife Area) along the St. Lawrence River, in southern Quebec, from 1993 to 1995. Circles, 0.2-ha in area, centred on six nests discovered at Ile aux Grues (the first nests reported east of Ontario in half a century), were characterized by herbaceous plants belonging to the Gramineae (Spartina pectinata), Cyperaceae (Carex paleacea and C. hormatodes) or Juncaceae (Juncus balticus). All nesting habitats (circles) had very high mean percent cover of live vegetation. All also had a well-developed senescent vegetation canopy from the previous year's growth. Habitats used at Cacouna and Lake Saint-François National Wildlife Area were dominated by the same plant families, although the species varied among localities (Carex paleacea, Scirpus maritimus, and Carex mackenziei at Cacouna; Carex lacustris, Calamagrostis canadensis, and Carex aquatilis at Lake Saint-François National Wildlife Area). Each habitat usually had shallow (12 cm) or no measurable standing water, but the substrate remained water-saturated throughout the summer. Although Carex sedges predominated in each habitat, we found that other graminoid plant species provided important cover. In our view, Carex sedges should not be considered the only indicator plant species of Yellow Rail habitat; we believe instead that the Yellow Rail, in common with other rail species, may tolerate considerable variation in certain, subtle features of its summer habitat, such as plant species composition, stem density, or height of vegetation. Habitat selection may be influenced primarily by plant physiognomy and maximum water levels. We also believe that the presence of a concealing senescent vegetation canopy constitutes a specific feature of Yellow Rail breeding habitat.