The highly gregarious Eared Grebe is best surveyed aerially (Cullen et al. 1999), but targeted aerial surveys do not exist for most breeding colonies. Thus, Canadian population trends must be inferred from continental data during staging and wintering. Christmas Bird Count (CBC) data suggest that, despite some strong fluctuations, the current North American abundance has shown little change relative to 1970. However, CBC results have low reliability because trends for Canadian breeders cannot be distinguished from the continent-wide trend, and because much of the population winters far offshore beyond the range of CBC coverage. This assessment is therefore considered to have low reliability. This may be improved once new information from targeted aerial surveys from Mono Lake, California and Great Salt Lake, Utah, where the majority of birds stage each fall, is available. The Eared Grebe is currently at an acceptable level relative to its national population goalat an acceptable level relative to its national population goal (see graph below).
Additional information on: Christmas Bird Count (CBC)
