| The Chinese Bulbul, Pycnonotus sinensis, is one of the most abundant and widely distributed birds of south China. From March to July in2012, we surveyed the Chinese Bulbul in the urban environment of Hangzhou, China. We aim to:1) gain a clearer perspective on their breeding ecology in urban environment,2) detect their responses in breeding behavior to urbanization. The main results were as follows:(1) Totally,117breeding nests were found. The Chinese Bulbul began to lay eggs in early April. Its average clutch size was3.37±0.48eggs (n=103), hatching success68.3%, fledging rate52.1%, and the total breeding success35.58%(n=117). The main causes of breeding failure included egg and fledgling predation, as well as human disturbance.(2) The Chinese Bulbul mainly nested on the trees of Osmanthus fragrans (84.6%, n=117) at residential area, street tree strip and green belt. The results showed that the average nest height from the ground is3.16±0.91m (n=117). Six factors were found to affect its nest site selection:the proportion of pavement (20.33%), the proportion of building (13.26%), the proportion of greenbelt (11.59%), the proportion of water (11.02%), the proportion of nudation (8.55%) and the type of lawn (8.10%). The nest height from the ground and the nest tree height increased significantly with urbanization index, but both concealments from upper side and lower side were not significant related to urbanization index. These results might indicate that under suitable nest concealment, increasing nest height is the major strategy for the Chinese Bulbul to adapt to urbanization.(3) The measurement of73nests show that major axis is12.06±0.90cm, minor axis 10.81±1.02cm, inner major axis7.57±0.68cm, inner minor axis7.57±0.68cm, nest height10.96±1.97cm, nest depth10.96±1.97cm, bottom thickness6.18±1.83cm, nest volume127.35±22.37ml. There is no significant relationship between urbanization and nest parameters. It implies that the Chinese Bulbul have not adjusted their nest shape and size to urbanization.(4) By analyzing the materials of73nests, we found that the nests materials generally could be divided into two main groups:natural materials such as grass blade, tree leaves, palm etc., and artificial materials such as plastics, paper, foamed plastic materials etc. We found that95.9%nests contained artificial materials in the outer and middle layers, but only8.2%nests included artificial materials in the inner layer. The weights of artificial materials in outer layer, middle layer and whole nest all increased significantly with urbanization. In more urbanization area, the Chinese Bulbuls tended to choose more artificial materials due to the lack of natural materials.(5) Mean incubation period was11.25±1.16d (n=32). The longest was14d and the shortest8d. Nest temperatures was relatively higher during13:00-16:00, and lower during4:00-7:00. Mean nest temperature was24.67±3.11℃(n=55). There was no significant relationship between urbanization index and incubation behavior parameters. The Chinese Bulbuls show no significant response in incubation behavior to urbanization.(6) Mean fledgling period was11.85±1.12d (n=47). The longest was14d and shortest8d. We recorded13nests by video camera from06:00to18:00. The lowest feeding frequency was during06:00-07:00, with3.03±3.76times. The highest feeding frequency was during16:00-17:00, with8.31±5.88times. The frequency of feeding nestlings increased significantly with urbanization index, but the frequency of plant food and animal food were not significant related to urbanization index. The results indicate that there might be more food resources for breeding Chinese Bulbuls in urbanized environment, no matter from plant food or animal food. |
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