ocr: UNUSUAL CALLS Many songbirds have fast, high-pitched calls that are very difficult to remember, even if you are an expert. But some calls are so distinctive that they instantly identify the bird that produces them. A typical example IS the Eurasian cuckoo, whose wo-note call IS one of the loudest and clearest in the bird word. The cuckoo IS a migratory bird and throughout Europe the cuckoo's call isa sign that spring has arrived. SEE ALSO
