Individuals of species found in many kinds of environments are often considered as ecologically tolerant. However, species found in a variety of environments may be composed of a suite of individuals with narrow, but different, niches (individual specialisation). My research will test whether individual specialization occurs in the White-throated Sparrow ( Zonotrichia albicollis ). In boreal forests, this species is found in a variety of forest stands, from recent clearcuts to mature stands. If individual specialization occurs in this species, site-fidelity by individuals from one year to the next should be higher in undisturbed stands compared to stands clearcut between two breeding seasons (while sparrows are in their wintering range). I measure site fidelity using breeding dispersal distances and return rates of males. I will try to test this prediction at the Forêt Montmorency, 75 km North of Québec city. In summers 2004 and 2005, we captured and color-banded over 150 male sparrows, about 50% in stands that were cut the following winter, and 50% in control stands. The project will continue in 2007.