IF YOU want to save a species you need to know how many individuals are left. But it turns out that simply counting animals at known hangouts is no good: rare species may be there, even when you can鈥檛 see them.
of West Virginia University in Morgantown and his team monitored , living on a nature reserve in Kazakhstan. Only .
The number of breeding birds is relatively easy to establish because they stay at their nests. But Katzner focused his study on young non-breeders. These can step in if the breeders die for any reason, and stabilise the population.
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The team used two methods to estimate numbers: counting the birds as they left their roosts, and collecting shed feathers for genetic analysis. In 2004, the genetic analysis identified 308 non-breeders, while visual surveys found only 21 ().
鈥淲hat you see isn鈥檛 what you get,鈥� Katzner says. 鈥淢ost conservation plans are centred around nests and breeding pairs. In reality there鈥檚 a cryptic population that you don鈥檛 see but is really important.鈥�
of the Zoological Society of London says genetic studies like these are crucial for monitoring endangered species, especially those that are tricky to observe conventionally.
