The Breeding Ecology Of Snow Partridge(Lerwa Lerwa)

During the breeding season,birds living in specific environment will choose corresponding breeding strategies to ensure the successful completion of breeding tasks.Birds living at high altitude often face the challenges of food shortage,low temperature,low oxygen and short breeding season.In this study,the selection of the breeding micro-habitat,the incubation rhythm and the characteristics of the life history of the Snow Partridge(Lerwa lerwa)living in the Qinghai-Tibet Plateau were studied to supplement the breeding data of Snow Partridge and to explore the adaptation strategies to the extreme high-altitude environment.The study sites are located in Basu County and Cuona County of Tibet Autonomous Region.The occurrence sites and nests sites of Snow Partridge were collected by line transect method,system search method,and playback and interview survey method.The environmental factors that may affect the microhabitat selection of Snow Partridge were recorded by sampling method,and the nest site selection and microhabitat selection of Snow Partridge were analyzed by Random Forest model.The daily activity rhythm of Snow Partridge was recorded and analyzed by instantaneous scanning method and focal animal sampling method.Record the incubation rhythm of snow quails by data-logger.The results of micro-habitat selection analysis during the breeding season of Snow Partridge showed that altitude was the most critical factor for habitat selection,and the nearest cliff distance and slope represented the terrain as the second important factor.Snow Partridges preferred to move around the ridge near the cliff and steep slope,which helped to avoid predators.Land cover is the third important factor,which may be related to food and avoiding predators.A total of 12 Snow Partridge nests were recorded All nests are cave nests,the bottom of the cave is slightly concave downward,with hay and feathers as the bedding for the eggs.The result of nest site selection suggest that the slope is the most important factor in nest site selection,and the road distance,the distance from the nearest cliff and the direction of nest opening are the second important factors;the remaining six environmental variables are the third important factors.Cave nest can reduce the energy consumption of adult birds.This study shows that Snow Partridges tend to improve their nest concealment when they are faced with the trade-off between nest concealment and vision,rather than finding nest predators early in advance to avoid them.Snow partridge eggs oval,light yellow color,eggshell surface uneven distribution of different sizes of brown spots.The clutch size was 4-5(mean = 4.71±0.45 eggs,n = 7 nests);the egg mass was between 28.1g-37.7g(mean=31.1±2.5g,n =28eggs).Compared with same parameters of other Galliformes,Snow Partridge has higher egg weight,fewer clutch size,and the proportion of single egg weight to female body weight is higher.The results showed that in order to adapt to the extreme environment of high altitude,Snow Partridge kept a high hatching success rate by increasing the investment in the offspring and reducing the number of offspring,which supported the K-selection strategy of "fewer clutch size and bigger egg".Females left nest 1-4 times a day(mean=1.8±0.7,n=39d).Usually,leave the nest every morning before sunrise.Most of recess occurred within 0.5 hours before sunrise and 1.5 hours before sunset.The time of the first recess was 06:01-07:09(mean=06:26±16 min,n=39 d).The duration of the first recess was 60 min-615 min(mean=179±102 min,n=39 d).The nesting rate of females was 85.2±6.9%(57.3%-92%,n=39d).The success rate of hatching was 87.9%.Compared with other related parameters of Galliformes,the characteristics of low nesting rate,bimodal recess time and less times of recess help Snow Partridges adapt to the alpine environment of the Qinghai Tibet Plateau.The less times the eggs leave the nest,the less energy they need to reheat,and the lower the risk of predation.The primary productivity of vegetation in high altitude areas is often lower than that in low altitude areas,and it takes longer for Snow Partridge females to find food.However,it may lead to delayed development of embryo,prolonged incubation period and increased possibility of egg predation.Therefore,the research results support that Snow Partridges may prefer the energy demand of hatching females and the potential future reproductive effect.