All coots do it till they have only one young (typically) - why? Beats me, I've heard explanations but they've all sounded like the things that swing between your legs
quotes 5-7 eggs and 0.38 juvenile survival, which I take to mean a 0.38 probability of any one juvenile surviving its first year. Hatching percentage not given but if 4 eggs hatch and 3 juveniles were killed survival would be 0.25 even without any other mortality. Am I missing something? One for the boffins, perhaps!
John, Mike & Pete,
There is a fair bit of discussion about this on the net – I really had no idea about it, however, there is a bit of video from David Attenborough, called ‘The Problems of Parenthood,’ which explains and shows this coot behaviour perfectly?
Pete - I think survival is usually expressed as young/ pair, not the proportion of young from a brood that survive. Which would equate back to the 1 surviving young per brood. This wasn't something I was aware of and it does sound bizarre.