One year point hearing survey of birds around sunrise in Oiso hills

Abstract

To survey the changes in avifauna, I recorded vocalizations at fixed point 30 minutes before and after sunrise almost every week for 1 year (45 weeks from July 2014-June 2015) at Oiso hills in Kanazawa Prefecture. I used only data obtained by bird vocalization for analysis. A total of 55 bird species, including introduced species, were observed (daily average = 17 species). The most species were observed in the second half of April (27 species) and the least was in September (5 species).

Start of vocalization according time(1) up to 30 minutes before sunrise: average of 25.4% ofspecies, including nocturnal species, began to vocalize.(2)1 hour sandwiching sunrise: 47.6% of species began to vocalize.(3) 30 minutes after sunrise: 25.4% of species began to vocalize. In the spring there were many diurnal bird species vocalizing (increasing at a rate of 1 species every 3 minutes).

In the autumn there were fewer birds vocalizing (increase rate of 1 species every 8 minutes). The time that diurnal birds being to vocalize varies between species.

Birds that have an annual incidence of 10% or more and start of vocalization half-width is within 10 minutes (in ascending order): Red-billied Leiothrix Leiothrix lutea, Japanese Bush Warbler Cettia diphone Hawfinch Coccothrautes coccothrautes, Brown-eared Bulbul Hypsites amaurotic, Bull-headed Shrike Lanius bucephalus, Hwamei Garrulax canorus, Narcissus Flycatcher Ficedula narcissina. This shows that these species begin to vocalize at a fixed time around sunrise. Birds that have an annual incidence of 10% or more and start of vocalization halfwidth is more than 1 hour (in ascending order): Barn Swallow Hirundo rustic, Japanese Paradis Flycatcher Terpsiphone atrocaudata. Bird species with a start of vocalization half-width larger than 30 minutes: Dusky Thrush Turdus eunomus, Blue-and-White Flycatcher Cyanoptila cyanomelana, Common Buzzard Buteo buteo, Japanese Grosbeak Eophona personata, Meadow Bunting Emberiza cioides. I have shown that the time of first vocalization and time variation between bird species makes it possible to classify them into 3 groups: diurnal visiting species, diurnal resident species and nocturnal species.