All over the park there are nests full of baby great tits. Video from WH Amazing Animals Share on your social media:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Like this:Like Loading... 2 thoughts on “” Why does the mother bird eat the eggshells. Is she just clearing up the nest? Each egg weighs about the same as 10% of the female’s body weight; a clutch of eight eggs is an enormous drain on her body. She eats the eggshells in an effort to recover some of the calcium and other essential minerals that she put into making the eggshell in the first place. Comments are closed.