Study On The Incubation Behavior And Foraging Habitats Selection Of Anser Indicus In Yanchiwan National Nature Reserve

The bar-headed goose(Anser indicus)is an endemic species in Asia.It is a monogamous bird and mainly reproduces in plateau lakes.Danghe wetland in Yanchiwan National Nature Reserve of Gansu Province is one of the breeding areas of bar-headed goose.From April to June 2019 and June 2020,the behavior of bar-headed goose during incubation period(Recorded 1 minute video and 3 photos per 5 minutes,6:00-20:00 every day,recorded 8082 minutes video and 9275 photos during incubation period)was recorded by infrared camera.The behavior time budget during incubation period was analyzed,the behavior law and the mating system were discussed,and the foraging habitat selection of bar-headed goose was analyzed.(1)The time budget: incubation behavior of bar-headed goose was divided into four categories,hatching,survival,defense and rest.Female bar-headed goose mainly hatch eggs(88.2±2.71%)without resting behavior.Male bar-headed goose did not directly participate in incubation,and their resting(66.41± 1.03%)and defense(10.61±0.73%)behaviors were significantly higher than those of females(P<0.01).In addition to foraging,the time budget of inter-sexual behavior was significantly different during incubation period.Male bar-headed is mainly responsible for warning.Resting behavior can be regarded as a ready defense and accompanying females,so as to ensure hatchings.Female bar-headed goose is fully invested in hatching.(2)The time budget of each behavior of bar-headed goose changed along with the incubation period.In order to further explore the energy distribution and the intersexual role of bar-headed goose,the incubation period was divided into three stages,the pre-incubation period,the mid-incubation period,the late-incubation period.In the pre-incubation period,the foraging of female bar-headed goose was higher than that in the mid and late incubation period respectively.In the late-incubation period,the foraging of male bar-headed goose was significantly less than that in the pre and mid period respectively.Preening in the mid and late period respectively was significantly more than that in the pre-incubation period.By reducing foraging and increasing preening actively prepare to take care of hatched goose.The male bar-headed goose maintains a high level of warning behavior throughout the incubation period,protecting nests,eggs and females.(3)Daily rhythms: the bar-headed goose usually foraged at a noon in the incubation period,the male bar-headed goose foraging more a peak than female,indicating that the male foraging intensity was greater than the female.Warning,preening,nest-tidying were changed with bar-headed goose foraging behavior.The behavior rhythm of bar-headed goose was related to the change of atmospheric temperature.When the temperature rises,female bar-headed goose increases foraging and reduces sitting nest accordingly,while male bar-headed goose increases foraging behavior and reduces resting accordingly.The bar-headed goose adapts to the changes of plateau environment by changing their behavior,ensuring successful reproduction.(4)The results showed that the perching on nest is the main behavior of females accounting for 88.13±1.28% in a day,leaving their nest 1.51±0.08 times and lasting for55.82±4.00 min,as well as turning egg 4.73±0.43 times.At different stages of the incubation period,there were significant differences in the ratio of perching on nest,the frequency and time length of leaving the nest,as well as the egg-turning frequency.There was a significant positive correlation between temperature and the frequency of leaving the nest and the time length of leaving the nest,and the frequency and length of leaving the nest increased with the rise of temperature.The hatching strategy has obvious environmental adaptability.In low temperature environment,the increase of sitting-nest rate is mainly to meet the needs of embryos,and in warm environment,the increase of foraging is mainly to meet their own survival.(5)Maintenance mechanism of single formulation of bar-headed goose during incubation period: the females are responsible for hatching eggs(setting nest,nest-tidying,turning egg),while males for the defense and accompanying females.In the late-incubation period,males actively prepare to take care of the early hatched geese by less foraging and increasing their preening.(6)The survey of foraging habitat selection showed that 132 plots(1m×1m)were established for sampling vegetation.Factors of its foraging habitat including vegetation species,vegetation height,vegetation density,vegetation coverage,the depth of water,the distance to water,the distance to grazing area,the distance to trail and other habitat factors were measured.According to the results of the vegetation composition of foraging habitats,Cyperaceae were found to have the highest frequency,accounting for more than 50% of the vegetation composition.The foraging sample was compared with the normal foraging sample,and it was found that the foraging sample had the following characteristics: the vegetation height was less than 10 cm,the vegetation density was higher than 500 plants per square meter,the vegetation coverage was mainly between50 and 75%,the depth of the foraging place water was less than 15 cm,far away from the interference,and near the water source.The principal component analysis showed that the main environmental factors affecting the selection of foraging habitats during the incubation period of bar-headed goose were food factors,interference factors,and safety factors.