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The Importance of Canada's Boreal Forest to Landbirds

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PART 2: HOW SIGNIFICANT ARE BOREAL LANDBIRDS THROUGHOUT CANADA, NORTH AMERICA AND THE WESTERN HEMISPHERE?

Winter Birds at U.S. Feeders: Project FeederWatch

Birds from Canada's boreal forest constitute about 17% of landbirds counted at feeders in the contiguous United States. This is a somewhat higher figure than the 10% of total birds estimated from Christmas Bird Counts. Sparrows and finches make up the bulk of boreal birds at feeders (Table 17). The boreal forest produces many other species of birds that are regularly attracted to feeders, such as chickadees, woodpeckers, nuthatches and jays, but most of those species are not migratory. Many boreal finches are migratory but a large proportion of their population remains in southern Canada.

Table 17: Project FeederWatch (PFW) indices of average abundance, by bird family         PFW Abundance Index % Shared All     Landbird Family Boreal Birds All Birds Boreal Migrants Landbirds     Emberizidae (Sparrows & Allies) 3.07 4.47 69% 19 36     Fringillidae (Finches) 0.65 5.02 13% 6 15     Turdidae (Thrushes) 0.09 0.30 31% 9 12     Corvidae (Jays, Crows & Allies) 0.09 1.81 5% 2 19     40 other Landbird Families 0.24 13.09 2% 99 262     Total Landbirds 4.13 24.69 17% 135 344

Dark-eyed Juncos are by far the most abundant of boreal birds at feeders in the U.S. (see Table 18), and Juncos exported from Canada's boreal are estimated to make up on average about nine % of all U.S. feeder birds. Juncos are numerically the most abundant species in 14 of 48 states, and one of the top five species in 39 states. "Snowbirds", as they are sometimes called, have the distinction of being recorded at the highest proportion of feeders in North America (Dunn & Tessaglia-Hymes 1999). American Goldfinches and Whitethroated Sparrows from Canada's boreal are also numerically important.

Table 18: Project FeederWatch (PFW) indices of average abundance, for species with most birds from Canada's Boreal Forest         PFW Abundance Index %     Species Boreal Birds All Birds Boreal     Dark-eyed Junco 2.20 3.06 72%     White-throated Sparrow 0.49 0.50 98%     American Goldfinch 0.34 2.02 17%     Pine Siskin 0.13 0.23 58%     Purple Finch 0.13 0.22 60%     White-crowned Sparrow 0.11 0.20 58%     American Tree Sparrow 0.10 0.20 49%     American Crow 0.09 0.44 20%     American Robin 0.08 0.22 36%     Chipping Sparrow 0.06 0.10 59%     Song Sparrow 0.05 0.20 27%     Northern Flicker 0.04 0.10 40%     Evening Grosbeak 0.03 0.07 50%     Yellow-rumped Warbler 0.03 0.04 74%     Red-breasted Nuthatch 0.03 0.15 19%

The distribution of boreal birds, expressed as a proportion of all birds at feeders, is shown in Figure 8. The proportion of boreal birds varies more than three-fold across states, from nine % in Florida to 31% in Oregon. The overall distribution is heavily weighted towards the distribution of Dark-eyed Juncos, which are slightly more abundant at feeders in the west (Dunn & Tessaglia-Hymes 1999).

Figure 8: Distribution of Boreal birds at U.S. Bird Feeders, from Project FeederWatch

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