We have been monitoring 10 kestrel boxes for the past three years with two pairs nest among these 10 boxes. This year one of our parents produced 5 eggs (like normal) as first indicated by us on 5/30. However, since then we have not seen these eggs hatch. At this point we are far beyond the normal incubation hatching period indicating that for some reason these are not viable. This momma kestrel is particularly protective too and is still attempting to incubate. My question is, what to do next. Do we remove the eggs to give her some time to grieve and reassess? Or do we leave them for her to eventually give up on? She rarely leaves the box on checks (done with an endoscope camera). Our other nest did extremely well and gave us a record of 6 eggs to chicks to fledglings.
This is a great question, and thanks for reaching out. The Migratory Bird Protection Act prohibits the disturbance of any active American Kestrel nest, and a nest qualifies as active if one or both of the adults are still around, even if the eggs are no longer viable. Kestrels have been observed continuing to incubate eggs for almost two months past the predicted hatch date, so this female may just need more time to figure out what has happened.
As long as the female is still attempting to incubate, the nest should be left alone other than whatever checks you have scheduled. Once she finally moves on (which could be another few weeks yet) the box can then be cleaned out and the nonviable eggs discarded.
Thanks again for asking, and for your participation in the American Kestrel Partnership. Hopefully your 2023 nests perform more like your other nest this year—six fledglings is an impressive feat!