Birth, and copulation, and death.
That’s all the facts when you come to brass tacks:
Birth, and copulation, and death.
I’ve been born, and once is enough.

Although not involved in bird study, these lines from T. S. Eliot encapsulate our current studies of wader populations on The Wash. Bird populations are sustained by recruitment of fledged young into the adult population at an equal rate to the death of individual adults. More recruitment than deaths equals more birds. Unfortunately, the opposite is currently occurring in Eurasian Curlew, which is experiencing population decline. This could be due to not enough chicks being raised to adulthood from each nesting attempt, or alternatively, it could be due to increased death of adult birds. Knowing which factor is more important allows conservation efforts to be prioritised: do we need to protect Curlew nests to improve chick survival or do we need to enhance protection of wintering Curlew to improve adult survival? A recently published paper has explored one part of the equation – survival in Curlew – using data from The Wash, as well as other wader ringers around Britain and Ireland.