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Every sperm is sacred

10,000 Birds

By studying Zebra Finches and domestic chickens, the scientists discovered that multiple sperm appear necessary for a fertilized egg to progress to the embryo stage (a process called “polyspermy”.) This differs from humans and other mammals, in which the addition of extra sperm essentially destroys the egg.

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Birding Shanghai in October 2022

10,000 Birds

Of course, it is hard to resist looking at a paper titled “Host personality predicts cuckoo egg rejection in Daurian redstarts” Basically, the personality of a female redstart (bold or shy) predicts the responses to parasitic eggs – bold hosts are more likely to reject parasitic eggs.

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