In this study,live fledglings of Nycticorax nycticorax and Ardeola bacchus at the Huangpu District of Guangzhou City were collected,and their primary feather,breast feather,tail feather,liver,chest muscle and egg shell were sampled for mercury determination.The results showed that these two heron species had a very similar distribution pattern of mercury concentration in their tissues and organs,i.e.,tail feather > breast and primary feather > liver > chest muscle > egg shell.Ardeola bacchus had higher levels of mercury in all its tissues than Nycticorax nycticorax.There were significant interspecific differences in mercury level for breast feather and primary feather.Because the collection of breast feather is easier and not harmful to birds,it is better to use it rather than primary or tail feather to monitor environmental pollution.The mercury level in breast feather was ten times higher than that in liver,lower than that in tail feather,but not significantly different to that in primary feather.The mercury concentrations in the tissues of Nycticorax nycticorax and Ardeola bacchus from Huangpu District of Guangzhou were similar to those from the suburbs of Chengdu,Sichuan Province,but lower than those from Taihu Lake,Jiangsu Province and higher than those from Hong Kong.
