Study On Breeding Biology Of Greater Coucal(Centropus Sinensis)

Greater Coucal(Centropus sinensis)belonging to the Cuculiformes,Cuculidae,Centropus,there were eight subspecies in the world,and it was a widely-distributed resident bird in Asia.South China was the main distribution region,but its population had declined rapidly for illegal hunting to make traditional Chinese medicine,was classified as the national secondary key protected wild animals.So far,there had been some studies about this species abroad,while was rarely reported at home.Study on breeding biology of Greater Coucal had been carried out to perfect the basic data in Nonggang Village,Longzhou County,southwest Guangxi,China from March to June,2016.The methods,such as line transect method,systematic search,tracking birds' behavior,and the equipments like automatic temperature recorder,infrared-triggered camera,camera had been used to study breeding season habitat selection,breeding behavior,egg and clutch size,incubation rhythm,nestling development,competition and threats and other aspects about Greater Coucal.The results were as follows:(1)There were 12 breeding nests of Greater Coucal had been found in the wild,10 of which had eggs,and successfully hatched 5 nests.44 eggs were recorded and successfully hatched 20 eggs,the hatching rate was 45.45%.16 chicks finally successful fledged,and the fledging rate was 80%.Breeding success was 36.36%.(2)The shape of Greater Coucal nest was an oval.The nest was built in Gramineous plants,and it was mainly by its mutual bend or inlay leaves composed.The nest opening tended to southwest.Nest height was 47.08 � 1.20 cm(n=12 nests),the width and length of nest were 36.42�1.33 cm and 42.75� 1.91 cm(n = 12 nests),and the height from ground was 1.73 � 0.14 m(n ?12 nests).Nest site more selected in the good hidden Karst mountain foot where close to farmland,less human disturbance and have tree.During the breeding period of Greater Coucal habitat preference for low altitude,species and quantity of trees was relatively small,tree and shrub coverage low but herbaceous cover high environment,at the same time love foraging in the farmland,especially the high vegetation coverage farmland.These were reflected Greater Coucal in habitat selection a trade-off between the process of breeding success and survival of their own.(3)The courtship behavior of Greater Coucal appeared in March,disappeared in mid May,and most active during the period of 06:00-10:00 and 16:00-18:00.Mating behavior often occurred during the period of 10:00-13:00 and 16:00-19:00,and in the brae of Karst mountain vegetation rich place.There was a kind of mating behavior occurred in the nest(nest mating behavior)had been recorded.Nesting behavior happened after confirming the mate,both male and female joint participation.Egg laying during nesting,every 2 days lay 1 egg,which lasted for 6-10 days.Both adults participated in incubation during the daytime,but only one bird incubated eggs at night.Usually,the one which in charge the job at night stayed at the nest around 19:00 and would lasting to around 06:00 of the next day.Feeding by the parents together,the brooding period was 17-19 days,average 18.25 � 0.48 d(n = 4 nests).Chicks within 6 days after hatched,needed parents to warm the young during morning and night,with increased age,time of warm young will gradually reduce.(4)The egg of Greater Coucal was oval,and white without spots.Egg weight was 16.35 � 0.51 g(n = 44 eggs),the width and length of egg were 28.46 � 0.38 mm and 36.11�0.42 mm(n = 44 eggs).Clutch size was 3-5 eggs,average 4.56 � 0.24 eggs(n=9 nests).Nest predation rate was 66.67%.There was correlation between clutch size and egg parameters or breeding parameters,and no correlation with nest size.According to the results,we believed that increasing clutch size was beneficial to the reproduction of the population,increasing the population continued insurance coefficient,and nest predation pressure was a key factor affecting the clutch size.(5)Incubation period of Greater Coucal was 12-19 days,average 16.75 �1.65 d(n = 4 nests),and it was no significant correlation with clutch size(r =0.865,P>0.05).The incubation strategy that the adults taken was lower leaving nest frequency and longer recess time.The length of activities was over 700 min(n?45 days)and 8.82 � 0.34 times(n = 45 days)of the recess per day.Average recess time was 52.91 � 2.35 min(n = 397 times)which has significant negative correlated to the ambient temperature(r =-0.113,P<0.05).The average incubation temperature in the nest was 31.7 � 0.3 ?(n = 4 nests)and increased with nest age.It was positive correlated to the ambient temperature(maximum temperature,r = 0.566;minimum temperature,r = 0.537;mean temperature r = 0.706,P<0.01)and the length of activities(r = 0.506,P<0.01).One nest was temporarily abandoned by parents during incubation and the nest temperature dropped to a minimum of 22.1 ? at night.(6)Brood size of Greater Coucal was 3-5,average 4 � 0.32(n = 5 nests).The external organ Logistics curve inflection point was body length(4.04 d)<tarsus length(6.70 d)?culmen length(6.72 d)<wing length(10.50 d)<tail length(11.97 d).Nestling growth can be divided into three stages,namely the T1 period(0-6 days old),tarsus length and body weight increased rapidly;the T2 period(7-12 days old),the indicators were growing rapidly;T3 period(13 days old to fledge),tail length and culmen length was growing rapidly,meanwhile,the wing length also developed greatly.The correlation between tail length and body weight was less than 0.9,and the other parameters were all above 0.9(P<0.01),had good substitution.Nestling growth followed the principle of the most important function of priority development,its high growth rate may relate to research area high nest predation rates,and it may also be a kind of adaptation to the changeable environment of nest site.Greater Coucal took the brood strategy of feeding more nestling in a short time,and the breeding strategy of increasing parental investment to ensure the nestlings'survival rate.(7)A total of 40 bird species were recorded in the Greater Coucal activity area,cluster analysis showed that Black-bellied Malkoha(Phaenicophaeus diardi)and Red Junglefowl(Gallus gallus)and Greater Coucal formed a group when the Euclidean distance d=8,had the potential competition.And the principal component analysis confirmed this relationship.At present,natural predator,diseases and parasites,chemical pollution,habitat lost and human hunting were important factors affecting population development.