新疆木垒波斑鸨的繁殖成功率

Breeding success of houbara bustard (Chlamydotis undulata macqueenii) population in Mulei, Xinjiang

作者于 1998～ 2 0 0 0年 4～ 7月 ,采用野外直接观察、栖息地植被样方调查和无线电跟踪等方法对分布于新疆木垒的波斑鸨 (Chlamydotiundulatamacqueenii)种群的繁殖生态进行了初步观察与研究。考察中共发现45个巢、 84窝幼雏。研究结果表明 ,木垒波斑鸨有两个产卵高峰期 ,表明雌鸟第一次繁殖失败后可能再次产卵。雌鸟营巢成功率平均为 0 5 0 5。波斑鸨的窝卵数在 2～ 6枚之间 ,出现 4枚卵的频率最高。第一产卵期内的平均窝卵数 ( 4 0± 0 8枚 /窝 )大于第二产卵期内的平均窝卵数 ( 3 3± 0 8枚 /窝 )。木垒波斑鸨种群三年间卵孵化率分别为 0 84、 0 80和 1,繁殖成功率为 0 45 6。种群在繁殖期几乎不受人类活动干扰 ,巢卵及幼雏损失主要来自天敌捕食 ,如沙狐、大和棕尾等.

Breeding success of the houbara bustard(Chlamydotis undulata macqueenii) was studied within a 3 050 km 2 area in Mulei, Xinjiang Uygur Autonomous Region in conjunction with radio tracking and vegetation sampling from April to June, 1998-2000. A total of 45 nests were monitored and 84 broods comprising 205 chicks captured, of which 82 were radio-tracked. The start of laying was different among the three years of study, however, the laying peak fell consistently between the 26th and 30th of April. A bimodal distribution in laying dates suggests the laying of a replacement clutches. Mean clutch size was 4.0±0.8 for the first clutch and 3.3±0.8 for the second clutch. Clutch size ranged from 2 to 6 eggs per nest from 1998 to 2000 with 4 being most common. The average clutch size was 3.9±0.8, 3.7±0.6 and 3.4±0.8 in each of the 3 years from 1998 to 2000 respectively. Average nesting success was 0.505 per female with large differences of 0.882, 0.406 and 0.227 in 1998, 1999 and 2000 respectively. Logistic regression was used to describe major differences between successful and failed nests. The distance to the closest fox den (m) was the only variable included in the model. The average distance to the closest fox den (m) was significantly longer at successful nests than at depredated nests (t=2.465, df=23, P<0.05). This suggests that fox predation is a factor affecting nesting success. Hatchability was 0.84, 0.80, and 1.00 respectively from 1998 to 2000. The average brood size on hatching was 3.3±0.8 in 1988, 3. 2±0.9 in 1999 and 2.5±1.0 in 2000. In 1999 and 2000 the decrease in brood size from stage A (1 to 5 days old) to stage B (6 to 28 days old) was 27.2% and 31.4%, respectively. In 2000, brood size decreased 37.5% from stage B to stage C (29 days to 56 days old) but remained nearly constant from stage A to stage C in 1998. Average chick survival per brood was 0.670 during the three years of the study. The proportion of females that lost their entire brood was 0.704 in 1999 and 0.452 in 2000. Only 42.2% of females that hatched eggs actually fledged young over the entire three years of the study. Predation, including that by foxes and buzzards, was the cause of brood mortality. The overall breeding success of the Mulei houbara population from 1998 to 2000 was 0.456, which means that a breeding female would, on average, fledge just 0.456 chicks .