At Presqu'ile provincial park, roughly 40 km to the south, the redstart is a common spring migrant in mid- to late-May, and in fall from late August to early October (LaForest, 1993, pp.326-327). Pairs nest in deciduous forest areas in the park, especially those with a thick understory. In Peterborough county, to the northwest, the redstart is recorded between 15 April and 9 October (Sadler, 1983, p.139).
The redstart is widespread in south and central Ontario (Cadman et al., 1987, pp.400-401). In the revised Bird Breeding Atlas (Cadman et al., 2007, pp.504-505) the redstart has retained its numbers, and typically starts nesting in mid-May.
References
Cadman,MD, Eagles,PFJ and Helleiner,FM (1987) Atlas of the Breeding Birds of Ontario. Federation of Ontario Naturalists and Long Point Bird Observatory, published by University of Waterloo Press, 617pp.
Cadman,MD, Sutherland,DA, Beck,GG, Lepage,D and Couturier,AR (editors) (2007) Atlas of the Breeding Birds of Ontario, 2001-2005. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, 706pp.
LaForest,SM (1993) Birds of Presqu'ile Provincial Park. Friends of Presqu'ile Park / Ontario Ministry of Natural Resources, 436pp.
Sadler,D (1983) Our Heritage of Birds: Peterborough County in the Kawarthas. Peterborough Field Naturalists / Orchid Press, Peterborough, ON, 192pp.