Urban birds' detectability is affected by inter‐ and intraspecific variation in shyness

Detection probabilities differ between bird species as a function of their life history and ecological and behavioural traits, inevitably introducing bias in their abundance and occupancy estimates. However, the effects of behavioural traits such as species shyness and vigilance on detectability remain poorly understood. Here, we estimated the species-specific level of shyness (estimated using flight initiation distance) and vigilance (alert distance) towards the human observer and their within-species variation for 18 bird species, and accompanied those with species detectability levels estimated during point counts in urban green areas in Prague, Czechia. We found that species detectability increased with inter- and intraspecific variation in birds' shyness, but was not associated with the inter- and intraspecific variation in birds' vigilance. Our study suggests that considering variation in birds' shyness towards human observers might increase the precision of species abundance and occupancy estimates during field surveys such as point and transect counts, at least in urban habitats.