Zoological Studies

Vol. 50 No. 1, 2011

Use of an Infrared Monitor to Record the Frequency and Timing of Parental Nest Visitation by the Blue Rock Thrush Monticola solitarius

Toshimitsu Nuka1,2,*, Yoshitaka Morikawa3, and Christopher P. Norman1,4

1Marine Biosystems Research Center, Chiba University, 1 Uchiura, Kamogawa, Chiba 299-5502, Japan
2Chiba City Wild Bird Society, 5-16-14-102 Makuharihongo, Hanamigawa-ku, Chiba 262-0033, Japan. E-mail:tnuka@hotmail.co.jp
3Faculty of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
4Japan Scientific Texts, 1709-5 Imafuku, Kawagoe, Saitama 350-1151, Japan

Toshimitsu Nuka, Yoshitaka Morikawa, and Christopher P. Norman (2011) We observed the nest visitation behavior of the Blue Rock Thrush Monticola solitarius by setting up an infrared monitoring system (IMS) at the entrance of a Blue Rock Thrush nest hole. Furthermore we carried out visual observations and video image analysis to confirm the IMS data and discuss the efficiency of the IMS. Two consecutive broods in 1999 (Apr.-July) and 1 brood in 2006 (Apr.-June) were monitored. The IMS recorded a consistent nest visitation pattern in all 3 broods. During the incubation stage, about 20 8 (mean S.D., n = 33) responses per day were recorded as the female emerged from the nest hole to feed at regular intervals. During the nestling stage, about 105 47 (mean S.D., n = 42) responses per day were recorded as the parents visited the nest hole to feed the chicks at about 10 min intervals. From the light intensity and IMS data, the daily activity pattern of the Blue Rock Thrush showed clear diurnal activity from before sunrise (-0.209 log Lum/m2) to after sunset (-0.100 log Lum/m2). The efficiency of the IMS was verified using video and visual observations, and around an 87% accuracy was confirmed. We concluded that after an initial confirmation of the efficiency of the IMS, the visitation behavior of Blue Rock Thrush in the incubation and nestling stages can be estimated using IMS data. For general monitoring of behavioral patterns, the IMS is weatherproof, requires minimal maintenance, and can be used for long-term monitoring. We concluded that the IMS is more efficient than using a video camera for monitoring hole-nesting animals because the time required for analysis is greatly reduced.

Key words: Incubation, Infrared monitoring system, Light intensity, Nest hole, Nestling.

*Correspondence: E-mail:tnuka@hotmail.co.jp