I studied under Tim Birkhead (the lead author) at Sheffield Uni on his first lecturing post and I think he has a good point. All this is theoretical but I agree with an early statement in it, that when the egg is full, that is has albumen and yolk or a developing embryo inside, the point of balance is different from an empty egg. Therefore when it rolls it does not roll in a small circle to avoid falling off the nesting ledge. As an assistant ringer in the past I have attended nests and when eggs are full they roll very differently than empty shells. The small circular rolling was surmised from spinning empty Guillemot eggs, not full ones! Great link Nick, thanks
Steve Suttill said
Wed Mar 8 10:31 AM, 2017
And if you really want to know more, read Tim Birkhead's "The Most Perfect Thing - inside (and outside) a bird's egg".
A highly recommended read even if Guillemots aren't your thing.
Nick Hilton said
Tue Mar 7 9:32 PM, 2017
Guillemot's eggs are pointed so they don't roll off cliff ledges, we all know that !
I studied under Tim Birkhead (the lead author) at Sheffield Uni on his first lecturing post and I think he has a good point. All this is theoretical but I agree with an early statement in it, that when the egg is full, that is has albumen and yolk or a developing embryo inside, the point of balance is different from an empty egg. Therefore when it rolls it does not roll in a small circle to avoid falling off the nesting ledge. As an assistant ringer in the past I have attended nests and when eggs are full they roll very differently than empty shells. The small circular rolling was surmised from spinning empty Guillemot eggs, not full ones! Great link Nick, thanks
A highly recommended read even if Guillemots aren't your thing.
Apparently not;
http://onlinelibrary.wiley.com/doi/10.1111/ibi.12458/full