I'm guessing, competing House Wrens. House Wrens will pierce eggs and evict tiny babies of ALL species nests near their nest. I guess for less food completion. If they see a nest box hole occupied by other wrens from their nest box vantage point, one will win out. Place boxes away from the sight of one another and you might not have as much fatality.
Alison Kondler Jefferson County -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/b47e8f6d-06a4-4cb1-aecf-2c10532c472f%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
