Songbird community composition versus forest rotation age in Saskatchewan boreal mixedwood forest

Abstract

Songbird communities were characterised using unlimited-distance point counts in four age-classes of boreal mixedwood forest in central Saskatchewan in 1991. Forest age-classes surveyed were: mature stands (50-60 years old), rotation age stands (80-90 years), old stands (100-110 years), and very old stands (>140 years). Ten species (Winter Wren, Troglodytes troglodytes; Golden-crowned Kinglet, Regulus satrapa; Ruby-crowned Kinglet, R. calendula; Swainson's Thrush, Catharus ustulatus; Tennessee Warbler, Vermivora peregrina; Blackburnian Warbler, Dendroica fusca; Magnolia Warbler, D. magnolia; Bay-breasted Warbler, D. castanea; Rose-breasted Grosbeak, Pheucticus ludovicianus and Evening Grosbeak, Coccothraustes vespertinus, were significantly more abundant in forest that was older than rotation age. Four of these species (Winter Wren, Tennessee, Magnolia and Bay-breasted warblers), reached their highest densities only in the oldest (>140) age class. Two species (Red-eyed Vireo, Vireo olivaceus, and Ovenbird, Seiurus aurocapillus) were significantly more abundant in forest that was rotation age or younger. In boreal mixedwood forest, habitat-selection patterns of songbirds suggest that many species, not also occurring in rotation-aged or younger stands, may require substantially older forest in order to persist.