Fig. 4
From: Nightlife in the city: drivers of the occurrence and vocal activity of a tropical owl
Heat maps showing variations of daily and masking noise and the vocal activity of the Mottled Owl (Ciccaba virgata) in relation to sampling sites and time periods. Shading represents the intensity of noise ranged from lower (− 100 dB) to higher levels (− 50 dB). Letters indicate sampling sites ranked according to green cover. A to R: 75–100%, S to T: 50–74%, U to Y: 25–49%, Z to Z2: < 25%