The consequences of seasonal interactions in migratory birds: from individuals to populations.

鸟类的长距离迁徙是世界上最令人惊奇的野生动物奇观之一，自亚里士多德时代以来一直困扰着人类。然而，尽管这种长期存在的兴趣和多年的研究，我们对迁徙行为的变化如何影响进行这些壮观运动的鸟类种群的理解仍然存在巨大的差距。例如，为什么有些鸟类比其他鸟类迁移得早，为什么同一物种的不同种群在不同的地方过冬或繁殖，为什么有些鸟类能养育后代，而另一些却不能？这些都是非常重要的问题，特别是在保护候鸟方面，但由于两个问题，这些问题仍然没有答案。首先，我们现在知道，我们不能孤立地把一只鸟在一个季节的行为看作是所有季节的事件，因为两者是密不可分的。例如，如果一只鸟定居在一个糟糕的越冬地区，它可能无法及时收集春季迁徙所需的资源，因此会晚到繁殖地，因此不太可能找到配偶。第二，要想知道一只鸟在一个以上的季节里都在做什么，我们需要能够跟踪它每年的迁徙，这是非常困难的。这种跨季节效应在决定迁徙物种的生产力和生存方面可能非常重要。我们的研究将使用在过去30年中从天鹅和鹅个体收集的大量数据（这些天鹅和鹅已经安装了独特的可识别的彩色和字母环），以调查不同季节的事件如何影响它们的种群。

Long distance migration in birds is one of the world's most astonishing wildlife spectacles and has puzzled humans for since the time of Aristotle. However despite this long standing interest and many years of study there are still huge gaps in our understanding of how variation in migratory behaviour influences the populations of birds that undertake these spectacular movements. For example why can some birds migrate earlier than others, why do different populations of the same species spend the winter or breed in different places, why do some birds manage to rear young while others do not? These are all very important questions, particularly with respect to the conservation of migratory birds, but they remain unanswered because of two problems. First, we now know that we cannot view the behaviour of a bird in a single season in isolation as events across all seasons as the two are inextricably linked to one another. For example if a bird settles on a poor wintering territory it may not gather the resources it needs to fuel spring migration in time and so would arrive late on the breeding grounds, and threrefore be less likely to get a mate. Second, to get an idea of what a bird is doing in more than one season, we need to be able to track it as it makes its annual migrations and this is very difficult. This type of cross seasonal effect may be very important in determining the productivity and survival of migratory species. Our study would use large amounts of data collected from individual swans and geese (that have been fitted uniquely identifiable coloured and lettered rings) over the last 30 years in order to investigate how events across different seasons influence their populations.