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And then there were winter finches.

Beginning in the late summer of 1997 and continuing through the winter of 1997-1998, a finch "superflight" occurred. In any given season, some species of the so-called winter finches (crossbills, redpolls, siskins, and Evening and Pine grosbeaks) undertake winter movements. These species are often tagged with this moniker; obviously, they are "summer finches" in many northern coniferous areas, but most birders only encounter them in the winter. What constitutes a superflight is when all, or nearly all, the species move in the same season. Ironically, this means that in superflight years some areas will have fewer than normal finches -- the areas the birds have vacated. In last year’s 97th Count, there was a major movement of Red Crossbills, Cassin’s Finches, and Lawrence’s Goldfinches into many lowland or southern areas of the southwest. That flight was not echoed in the 98th Count. In the core range of many of these species in the continent, the northern Rockies and west central Canadian evergreen forests, in the 98th Count there was a dearth of winter finches. These were the areas that the nesting species had vacated.

Crossbills, redpolls, and Evening Grosbeaks began moving early; the Pacific coast, eastern Canada, the Northeastern US, and the mid-west all experienced an influx of these species during the 98th Count.

The push continued through mid-winter; crossbills and redpolls notably spread eastward and southward until late February.

What apparently drives these flights are food resources, with each species dependent on slightly different seed crops. A superflight event implies that large geographic areas had major failures of most seed crops. Interestingly, what could drive these movements are unusual weather patterns in the summer season prior to the Count period. Under El Ni–o conditions, abnormal patterns of drought and flood occur on a global basis. These could affect seed crops continentally, which in turn could induce entire populations of "winter finches" to vacate their normal haunts. It will be interesting to see if there is any long-term correlation between major El Ni–o events and winter finch superflights the following season.

The BirdSource website and historical CBC database will facilitate analyses such as this.