So far our choughs have laid sixteen eggs this year – and there may be more to come from nest four.
Given the ages of some of our breeding birds, we have taken the step of checking all eggs laid to see how many potential chicks to expect. We quickly took the eggs in turn from each nest and tested them by “candling”. (These days we don’t hold the eggs up to a candle, but use the LED light from a smartphone).
The results were slightly disappointing – with only the eggs in nests two and three being fertile. However, as all the pairs have taken such great time and energy to produce nests, we decided to share the fertile eggs into the infertile nests. We would then put the infertile eggs back in to replace the fertile ones taken. This meant that each successful nest would only have to rear two chicks, spreading the load on the parents.
Each of the laying pairs now has two fertile eggs to deal with. Two chicks have hatched in nest three, but sadly the younger chick died almost immediately after hatching.
Nest five also has a chick, with another expected to hatch soon. Both sets of parents are doing very well, taking turns to feed the tiny chicks. Hopefully, in the next few days all the remaining fertile eggs will hatch. The infertile eggs will be left in the nests for a few days, as they act as good heat stores when the females are off the nests.