Chestnut-sided Warbler Dendroica pensylvanica
Point Pelee and Rondeau, Ontario May 2005

The Chestnut-sided Warbler breeds from central Canada east to the Maritime Provinces, south through New England and the Great Lakes and through the Appalachian Mountains to northern Georgia. It nests in early to middle successional habitats where it prefers deciduous, brushy areas, and winters in central Mexico south through Central America.

The species is sexually dimporphic: males are more brightly and strongly coloured than females with longer “chestnut-sides”. Females also tend to have a greener crown than the males. Younger males are said to have a shorter less well-marked chestnut flank stripe.

Both adults and first-years may moult their greater coverts creating a contrast in the feathers, and using covert wear and/or contrast between new and old feathers is not a reliable guide to ageing.

Jon Curson in the Helm guide “New World Warblers” (J. Curson et al, Helm 1994) states that this species is one of the few warblers to have benefited from forest clearance as it prefers scrub and young growth (from “very rare” 150 years ago it is now one of “the commonest eastern warblers”), but the Warbler Watch website says that “Populations of Chestnut-sided Warbler are declining in the Southeast, probably due to habitat loss and fragmentation. More northern populations are stable or undergoing local population declines.”
(Adapted from Warbler Watch: Chestnut-sided Warbler, which also has a wav. recording of the song)

Figure 1: Male, Rondeau, 19 May 2005

 

Figure 2: Male, Rondeau, 19 May 2005

 

Figure 3: Male, Rondeau, 19 May 2005

 

Figure 4: Male, Rondeau, 19 May 2005

 

Figure 5: Male, Rondeau, 19 May 2005

 

Figure 6: Male, Rondeau, 19 May 2005

 

Figure 7: Male, Rondeau, 19 May 2005

 

Figure 8: Male, Rondeau, 19 May 2005

 

Figure 9: Male, Rondeau, 19 May 2005

 

Figure 10: Male, Point Pelee, 18 May 2005

 

Figure 11: Male, Point Pelee, 18 May 2005

 

 

Figure 12: Female, Point Pelee, 18 May 2005

 

Figure 13: Female, Point Pelee, 18 May 2005