REPRODUCTIVE-PERFORMANCE, RECRUITMENT AND SURVIVAL OF WANDERING ALBATROSSES DIOMEDEA-EXULANS AT BIRD-ISLAND, SOUTH-GEORGIA
REPRODUCTIVE-PERFORMANCE, RECRUITMENT AND SURVIVAL OF WANDERING ALBATROSSES DIOMEDEA-EXULANS AT BIRD-ISLAND, SOUTH-GEORGIA
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DOI：
10.2307/4895
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发表时间：
1990-06-01
影响因子：
4.8
通讯作者：
PRINCE, PA
中科院分区：
文献类型：
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作者：
CROXALL, JP;ROTHERY, P;PRINCE, PA
自1961年以来，南格鲁吉亚鸟岛的流浪信天翁繁殖种群以每年1.0%的速度下降。类似的下降也发生在亚班尼特的其他地方。利用1958年、1962年、1963年和1972年以来重新捕获的幼鸟的详细数据，我们研究了自1976年以来繁殖成功率、繁殖频率、存活率和招募率下降的相对重要性。繁殖成功率（平均64%）每年增加1.2%，孵化和雏鸟成功率的增加同样重要。繁殖频率保持不变，除了繁殖成功率越高意味着更多的鸟每两年繁殖一次。在成功的繁殖者中，分别有72%、8%和6%在2年、3年或更长时间后繁殖;在不成功的繁殖者中，分别有68%、14%和6%在1年、2年或更长时间后繁殖。繁殖种群的招募率从20世纪60年代的36%下降到现在的30%;第一次繁殖的平均年龄也下降了。成年存活率平均为94%;女性比男性低2%; 20世纪60年代的存活率可能高出1-2%。一个人口模型的开发，密切配合所观察到的变化，并给出人口减少率每年0.9和1.1%之间。种群数量减少的原因主要是在繁殖季节之外（因为繁殖成功率高）;已知状态的鸟类的少数恢复支持这一点。关于延绳钓捕捞金枪鱼过程中死亡的鸟类的新数据（直接观察、振铃回收）有力地加强了早先关于低纬度地区捕捞活动造成的附带死亡率很重要的建议。鸟岛成年鱼的年死亡率可能超过2-3%，幼鱼的年死亡率可能超过15%。
The wandering albatross breeding population at Bird Island, South Georgia has declined since 1961 at a rate of 1.0% per annum. Similar declines have occurred elsewhere in the Subantarctic. Using detailed data on recaptures of birds ringed as chicks in 1958, 1962, 1963 and 1972 onwards, we examine the relative importance of changes in breeding success, breeding frequency and survival and recruitment rates to the decline since 1976. Breeding success (average 64%) has increased by 1.2% per annum, with increases in hatching and fledging success about equally responsible. Breeding frequency has remained constant, except that higher breeding success means more birds breeding biennially. Of successful breeders, 72%, 8% and 6% breed 2, 3 and more years later, respectively; of unsuccessful birds, 68%, 14% and 6% breed 1, 2 and more years later. Recruitment to the breeding population has decreased from 36% (of a cohort) in the 1960s to 30% nowadays; average age of first breeding has also decreased. Adult survival averages 94%; females have a 2% significantly lower rate than males; survival in the 1960s was probably 1-2% higher. A demographic model is developed which closely matches the observed changes and gives rates of population decrease between 0.9 and 1.1% per annum. The causes of the population decrease must operate mainly outside the breeding season (because of high breeding success); the few recoveries of birds of known status support this. Earlier suggestions that incidental mortality due to fishing activity in lower latitudes is important are strongly reinforced by new data (direct observations, ringing recoveries) on birds killed during long-line fishing for tuna. Annual mortality rates may exceed 2-3% of Bird Island adults and 15% of juveniles.