. The Canadian field-naturalist. Natural history. 426 The Canadian Field-Naturalist Vol. 115 was surveyed consistently for 18 years (1979-1996) by the same observer (Muriel Carlson). The number of species detected per year on the Brightsand route declined sharply between the 1980s and 1990s. Starting in 1990, species richness began to decrease, and by 1995, only 67 bird species were recorded on this route compared to a high of 105 species in 1987. Of those species still recorded on this route, almost all are declining and many of these declines are sig- nificant. In order to determine if speci
. The Canadian field-naturalist. Natural history. 426 The Canadian Field-Naturalist Vol. 115 was surveyed consistently for 18 years (1979-1996) by the same observer (Muriel Carlson). The number of species detected per year on the Brightsand route declined sharply between the 1980s and 1990s. Starting in 1990, species richness began to decrease, and by 1995, only 67 bird species were recorded on this route compared to a high of 105 species in 1987. Of those species still recorded on this route, almost all are declining and many of these declines are sig- nificant. In order to determine if species declines were related to local changes in habitat, or were a more widespread phenomenon, we examined other BBS routes surveyed consistently for long periods (, >20 years) both in forest fringe and in continuous forest habitat. Four additional routes with a similar suite of species were added to the analysis; Athabasca, Alberta, surveyed for 26 years by John Kinnaird; Two Hills, Alberta, surveyed for 14 years by Graham Greenle and the last 12 years by David Ealey; Clouston, Saskatchewan surveyed for 23 years by Maurice Mareschal; and Tyndall, Manitoba, surveyed for 26 years (22 by Rudolf Koes). We chose the BBS Bird River, Manitoba, as a control route. Bird River is the longest running BBS route (surveyed for 21 years by Peter Taylor) located in continuous forest habitat in the Prairie Provinces. Study Area Brightsand, Saskatchewan (53° 30' N, 108° 40' W), Clouston, Saskatchewan (53° 06' N, 105° 51' W), Athabasca, Alberta (54° 50' N, 113° 06' W), Two Hills, Alberta (53° 44' N, 111° 32' W ), and Tyndall, Manitoba routes (50 04' N, 96 36' W), are all located in the Boreal Plain Ecozone (Acton et al. 1998). This ecozone extends across Prairie Canada from southeastern Manitoba to northwestern Alberta and is bounded by the Precambrian Shield to the north and Aspen Parkland to the south (Figure 1). The Boreal Plain Ecozone is a gently rolling plain that was originall
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