Cuckoo Statistics

I was fortunate enough to see and hear a pair of cuckoos this morning, and I
got to wondering about the statistic that a female cuckoo lays up to 13 eggs
in a season. How was this figure arrived at? If it is that each female
cuckoo has a unique pattern to her eggs, the researchers must have worked
very hard and been very lucky to find thirteen nests, each containing a
cuckoo egg!

Best wishes
Daphne


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