her biological son.

A rare case of polygamy appeared as male 4 S, orange left, (98), mated neighbouring females  
2 %, orange right, (96) and bachelor german female C/A yellow right, (98). Both females incubated in 600 m distant nests. 4 S only fed 2 %, who reared three chicks.  C/A failed after having incubated during three weeks as she had to go fishing with 48 hours intervals.

               Female 2 %, orange, right, (96).  

          German female C/A yellow, right, (98) 

…. probably for the first time after his first migration, to mate with a german female, black E78, on a quickly made nest on a stump of a tree, close to the Loire river. The pair “separated” after 3 weeks, before any eggs were laid. I did not find  AL black until late August, then mating GY green, “his biological grand- mother” at her usual nest. Her regular mate had disappeared in the breeding season and  AL was not yet “accepted” to land on GY’s nest before this “new potential pair” migrated in September.

2004, GY green came back to her old nest and mated with AL black and the pair produced and fledged young, see table, for the next following 5 years. In the last year, 2008, AL black disappeared in mid June leaving GY green with 4 young in the nest. The nest was monitored frequently in June, July and August, but AL black was never observed.

  Number of young fledged that were produced by this pair, « grandmother » G/Y green and her « grand- son », AL black

                                      2008

According to experiences in Europe it is unusual that one partner in a pair manages, alone,  to fledge one or several young.