A systematic breeding survey of the avifauna of Colonial Point on Burt Lake, Cheboygan County, Michigan--a comparative study.

Abstract

Numerous studies detail significant population declines in migrant birds across eastern North America. Knowledge of these declines comes from the Breeding Bird Survey (BBS) along with its reservations and other long-term studies. We attempted to determine if birds, especially long-distance migrants, have been declining in Northern Lower Michigan. Transects (2) were surveyed in an old-growth northern hardwoods forest surveyed initially in 1946. Using GPS and plot mapping, species territories were determined based on singing males. Comparison of 1946 and 2005 indicate that all classes of birds, permanent resident (PR), short-distance migrant (SDM) and long-distance migrant (LDM), increased in absolute density. LDM maintained their core presence as the densest breeding group with however, a proportional drop in overall breeding density. Composition of the majority of the LDM breeding class (9 members) remained the same with much internal reorganization. The general increase and species-specific decreases were not attributable to any specific factor, but procedural error, overall general decrease of all migrants, climate change, and especially the changing local landscape may have had some effect on populations. These findings would best be used in future long-term comparable studies.