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New Microscopy Reveals Causes of Unhatched Eggs in Endangered Birds

10/2/2025

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Summary

Story summary

A team from the University of Sheffield and the Zoological Society of London (ZSL) finds early embryonic mortality, not fertilization failure, causes unhatched eggs; 65.5% of unhatched eggs were fertilized.
Advanced fluorescence microscopy yields a more accurate assessment of egg viability.
ZSL conservation zoos apply these diagnostics to boost endangered Sihek kingfisher breeding, with nine hand-raised Sihek released last year.

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Story summary

A team from the University of Sheffield and the Zoological Society of London (ZSL) finds early embryonic mortality, not fertilization failure, causes unhatched eggs; 65.5% of unhatched eggs were fertilized.
Advanced fluorescence microscopy yields a more accurate assessment of egg viability.
ZSL conservation zoos apply these diagnostics to boost endangered Sihek kingfisher breeding, with nine hand-raised Sihek released last year.