[obol] Barn Swallow mystery

[David Koskamp]

About 2-3 weeks ago a pair of barn swallows, I believe the same pair who nested above my front door last year, returned to build a new nest right off my front entryway.  A little under a week ago she laid eggs and they've been busy on the nest since.  I took the chance to spy inside via a ladder when they left the nest briefly and I managed to spot three eggs.

All seemed well and good but this afternoon after a run I was taken aback to see three broken eggs on the ground.  I am really puzzled at what happened given the nest's relatively secure spot.

Do you think the parents knocked them out somehow knowing they weren't developing?  Would another bird have felt threatened and raided the nest when the chance was there?  Will barn swallows "double clutch" if something happens to the first eggs laid?

Here are some pictures which show including of one of the nest setup.
http://fettster.smugmug.com/gallery/5268484_zbvuA#320725413_TuBCD

Let me know if you have any thoughts on this mystery.

-David





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