The Lincolnshire Bird Club

Just an update on owl box checking so far. Little Owls have also had a poor breeding season. Of 24 pairs in our boxes this year, only 47 young have fledged. Upon inspection, eggs that failed to hatch, appear to have been infertile suggesting that Little Owls were in poor condition at start of the season.
Kestrels also seem to be fairing badly especially in the Sleaford to Lincoln area.

Alan

Alan, with my farming background - the bulk of which was spent in the poultry industry, I feel it is unlikely that the poor 'fertility' you are reporting from the nests of Little Owls is due to the condition of the adult birds. The females would have had to be in good condition initially in order to have laid their eggs and it is doubtful that the males would differ greatly in weight.
Without very close examination of the 'clear' eggs it is near impossible to establish whether or not they were truly infertile. In some cases there may be a day or two of cell division followed by very early death of the embryo. It needs an experienced eye to spot this.
I hope that there is not something more sinister behind your findings !

Regards,
Roy.

Roy - You are quite correct in that I had merely assumed that eggs were infertile and have not yet had any results back from analysis. My supposition was based upon the fact that Little Owl females are extremely 'tight sitters' and it was clear that eggs had not been abandoned. One bird was known to have incubated a clutch of three eggs for at least five weeks.

Alan