Mostly, the common tern eggs are a khaki-tan color with darker speckling. But some of them are greener, and a rare few are almost robin's-egg blue. I asked Helen what that was about, and she said she wasn't sure but thinks that perhaps it's diet-related. She says she notices a color change, for example, when there are a lot of anchovies about. It's really interesting that mostly (per my observations, anyway) these variations seem to be nest-to-nest, but every so often you find one like this, with very different-looking eggs in the same nest.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/31852224@N00">Michelle Kinsey Bruns</a>
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<p><a rel="nofollow" class="external text" href="https://www.flickr.com/photos/sapphir3blu3/3593033259/">Common Tern Nest with Three Eggs (2)</a>
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