The researchers analysed the family trees of the species studied and found one key similarity.

研究人员对所研究的鸟类的家谱进行分析后发现一个关键的相似点。

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This election season is an ideal time to look into the family trees of our candidates and their critics to learn more about the ties that make them all part of this great country.

选举时期是研究候选人及其批评者家谱的良机，可以借机了解他们之间的血缘关系。

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Perhaps when you next go for a walk with your family, you can examine the trees you pass to see its age.

也许当你下次和你的家人散步时，你可以检查你经过的树，看看它们的年龄。

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If you go back on average 1.77 times further again (35 generations) everyone in the population will have exactly the same set of common ancestors (although they will be related, of course, through different routes in all the different family trees).

BBC: Family trees: Tracing the world's ancestor

Its meticulous records from church documents and sagas, a set of semihistorical books, let the 290, 000 residents trace their family trees to the earliest days.

FORBES: Icelandic identifiers

Mr Taylor also said "homecomers" enjoyed a richer experience if local people, museums and businesses have knowledge about the process of tracing family trees and were able to plan how to meet the needs of visitors.

BBC: North Highland College launches online ancestry courses