THE BREEDING BIOLOGY OF THE SHAG PHALACROCORAX ARISTOTELIS ON THE ISLAND OF LUNDY, BRISTOL CHANNEL
THE BREEDING BIOLOGY OF THE SHAG PHALACROCORAX ARISTOTELIS ON THE ISLAND OF LUNDY, BRISTOL CHANNEL
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布里斯托海峡兰迪岛上鸬鹚的繁殖生物学
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
B. Snow
中科院分区：
文献类型：
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作者：
B. Snow
摘要
1.在1454-1957的4年间，伦迪河流域的繁殖量基本保持不变。大多数筑巢地点每年都会被使用。死亡率是由旧巢址的再利用和有颜色标记的鸟类的回归而得出的。
2.各年龄段的启动时间以3~4周为多，不同年份的启动日期相差1~6天。
3.岛上不同地区使用不同类型的NCST-Site和NCST-Nest材料。较大的巢比较小的巢更成功。
4.1954-1958年五年的平均窝卵数为307枚，每年的变化幅度约为0-4枚。离合器的大小随着季节的推进而减少。
5.孵化从c/3中的第二个卵子开始，但在c/4中一天或更晚。
6.1954-1957年的孵化成功率仅在69%至73%之间。不孕不育是孵化失败的主要原因。
7.1957年和1958年对鸡蛋进行了称重和测量。在每一年中，较大的卵比较小的卵含有更大的蛋。1957年的平均蛋重(当时卵子更大)比1958年更大。这是由于较高的比重造成的。
8.初出茅庐的成功率为90%-95%，1956年除外，当时为67%。今年更严重的损失似乎是由于粮食短缺。大多数雏鸟的损失发生在前十天。
9.1957年对雏鸡的生长发育进行了研究。公鸡在30日龄时往往可以通过体重较重来区分。一窝中的第四只雏鸟在羽化期的前半段通常低于平均体重。
10.一些有标记的幼鱼在离开鸟巢后仍留在岛上长达50天。在这段时间里，他们表现出对父母的部分依赖。
11.较晚的离合器不如早期的离合器成功。在狭窄的悬崖上筑巢不如在其他地点筑巢成功。
SUMMARY
1. In the 4 years 1454–1957 the breeding population of Shags on Lundy appeared to he static. Most of the nest-sites were used each year. Mortality was deduced from the re-use of old nest-sites and the return of colour-marked birds.
2. Most of the clutches were started during a period of 3 to 4 weeks in each year but dates varied by as much as 1 6 days in different years.
3. Different types of ncst-site and nest-material are used on different parts of the island. Larger nests were more successful than smaller ones.
4. The mean-clutch size for the five years 1954–1958 was 307, varying annually by us much as 0–4 egg. Clutch-size decreases with the advance of the season.
5. Incubation starts with the second egg in c/3 but a day or more later in c/4.
6. Hatching success 1954–1957 varied only between 69 and 73%. Infertility was the mam cause of hatching failure.
7. Eggs were weighed and measured in 1957 and 1958. In each year the larger clutches contained larger eggs than the smaller clutches. The mean weight of eggs was greater in 1957 (when clutches were bigger) than in 1958. This was due to a higher specific gravity.
8. Fledging success was 90–95%, except in 1956 when it was 67%. The heavier losses in this year appeared to be due to food shortage. Most chick losses occur in the first ten days.
9. The growth of chicks was studied in 1957. Male chicks can frequently be differentiated when 30 days old by their heavier weights. The fourth chick in a brood is normally below average weight during the first half of the fledging period.
10. Some marked juveniles remain on the island up to 50 days after leaving the nest. During this time they show partial dependence on their parents.
11. Later clutches are less successful than early clutches. Nests situated on narrow cliff ledges were less successful than nests at other sites.