Lawrence Peregrines: addled egg, not hatching

May 18, 2018 in In the Nest Box, lawrence peregrines

Just after sunrise at 5:17 AM it was mostly cloudy, wind from NE at 13 MPH and temp at 58F.  The forecast calls for mostly sunny skies, with a high near 60. East wind forecast at 11 to 13 mph.

IMG_6837The female was observed around 6:20 AM this morning feeding those always hungry and growing chicks!  The fourth egg has not hatched, and at this point, it is unlikely to hatch.  In prior years, the falcons have had unhatched eggs.  An unhatched egg, may also be referred at as an addled egg.  This is an egg in which the developing embryo has died. Not to be confused with a clear or infertile egg, though in common usage the term is often applied to any egg gone bad.

IMG_6852Around 6:20 PM, after a lot of vocalizing, the female was provided with another meal, by the male for the chicks.  The photo shows the female returning to the nest box, with prey in her bill.  The bird in her bill has been stripped of feathers and is ready for her to rip apart for feeding purposes.  Also visible is the remaining unhatched egg.  This type of egg becomes known as as addled egg. Addled eggs are usually left, and may survive after the young have gone as dried and bleached relics, kicked to the side of the nest box, but they are often broken and trampled to pieces!

Literature cited:

Ratcliffe, D. 1993. The Peregrine Falcon. 2nd ed. Carlton, England: T. and A. D. Poyser.