| From March to mid-November 2004, we utilized the methods of on-the-spot surveying , measuring , observing , comparing and combining geographical information system on the research of theCommon Cormorant (Phalacrocorax carbo) in Majuan Island in Wusuli River. The research included breeding ecology (include prophase of breeding period, breeding period, posterior breeding period), feeding habits, songs and breeding habitats, etc. of Common Cormorants. The result showed that: Common Cormorant came back to Wusuli River from late March to mid-April. They began to build their nests in mid- or late April and mated at the same time. Their nests' distributions presented the type of cluster. The utilization rate of old nest was up to 92.93%.Common Cormorant generally laid 3-4 eggs for each clutch, usually every two days laying one egg, with the weight of 52±16.85g and the size of (5.84±0.28) × (3.61±0.16) cm. The parents cooperated to hatch, hatching with that laying, the female bird hatching longer than the male. The incubation duration was 28 days, the hatch temperature was 38.2°C-38.9°C, the weight loss rate of eggs was 22.7%, and the hatching rate was 93. 6%. During the process of hatching, replacing other alien bird eggs into its nest artificially, we didn't find cormorants exclude those eggs. The nestling began to leave their nests at the beginning of July, till the beginging of Augst most of them had leaved. The autumn migriate began at the mid-Augst, till the beginning of September, they migriated in large colonies, the largest colony were 890, they left Wusuli River at the beginning of Novmber.The weight of fresh nestling did not influence their growth. The parents cooperated to foster their nestling, feeding some half digested fish in 1 -8 Days; feeding some undigested small fish in 8-35 Days, such as Leuciscus waleckii, Rhodeus sericeus, Hemibarbus labeo, Saurogobio dabryi, Carassius auratus, Aristichthys nobilis and so on; feeding big fish after 35 Day, for example, like Black carp (Carassius Carassius) of 18cm in length and catfish (Silurus asotus) of 30cm length. Under artificial feeding the weight of nestling increased faster and the adults are bigger than under wild condition. Under above two conditions, the weight growth curves of the nestling were both shown as Logistic curve. The body temperature of nestling maintained at 38.9±0.52°C after 20 days old . Thermostatical ability came forth later than early-birds. The reproductive capacity is1.84, productivity is 1.673.The analysis of songs shows that: The sound frequency of the nestling was higher than adults, but the time was shorter than adult and the syllable number was difficult to be differentiated in younger than 20 Days' nestling; the frequency at alertness was higher than at hungry.In Majuan Island, Common Cormorant and Gray Heron (Ardea cinerea) are dominant birds, and White-tailed Sea Eagle (Haliaetus albicilla) is their natural enemy. Mallard {Anas platynchos) and Common Teal (Anas crecca) are common, and other birds are rare. In the nesting site of Common Cormorant, the height of nesting trees remarkably differed with non-nesting trees. Among those Common Cormorants' nesting site, Gray Heron's nesting site, their mix nesting site, and other districts, the height and chest-height diameter of trees remarkably differ each other.Main factors influencing Common Cormorant population are destruction of habitat, pollution of rivers, human economic activities and natural enemy. In addition, paroxysmalterrible weather, such as strong wind and lower temperature, can greatly influence Common Cormorant's breeding and survival.
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