Researchers say they have discovered widespread declines of many species, from American kestrels to olive-sided flycatchers . The researchers surveyed 61 sites in the desert and found that, on average, there were 43 percent fewer species of birds than a century ago.

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Researchers say they have discovered widespread declines of many species, from American kestrels to olive-sided flycatchers . The researchers surveyed 61 sites in the desert and found that, on average, there were 43 percent fewer species of birds than a century ago.