To effectively monitor bird populations, accurate identification of species is critical. However, the reliability of species identification is rarely taken into account or quantified. For this study, bird call data was collected using automated acoustic recording devices (ARDs) over a 3-year period. We then compared the results from experienced ornithologists who independently identified bird calls from the same samples. Results were highly variable.
Birdsong has evolved to help individual birds attract mates and defend territories. The breeding season is a critical period in the life history of many songbird species and previous studies indicate that bird vocal behaviour changes at the onset of breeding season. In this study, we compared the complex songs of a seasonal-breeding New Zealand honeyeater, the tui (Prosthemadera novaeseelandiae), between breeding and non-breeding seasons.
The suitability of line-transect-based distance sampling to robustly estimate population densities of bellbird (Anthornis melanura), kererū (Hemiphaga novaeseelandiae), North island tomtit (Petroica macrocephala toitoi) and tūī (Prosthemadera novaeseelandiae) during concurrent multi-species surveys was investigated. Densities were estimated annually from 2006 to 2009 at three sites within the Coromandel Forest Park, New Zealand.