(To watch this 34 second video clip, you may have to hit the spacebar or Enter to activate the control.) House Wrens have been known to destroy bluebird and other cavity-nester's eggs by piercing them, and then often removing them from the nest. Althea Shermanreported that House Wrens destroyed eggs of 29 different birds. They can remove an entire chickadee nest in a matter of hours.
This wren was caught in the act on my infrared nestbox camera. It is attacking House Wren eggs, probably in a competitor's nest. The entire attack lasted a matter of seconds. Notice that the House Wren makes a pretty big hole in the center of the egg, as opposed to the two tiny holes sometimes seen when House Wrens remove an egg from a box. It eventually removed all the egg fragments.
Reminds me of the shower scene in the Hitchcock movie Psycho.
Nature is NOT putting up boxes for the birds to nest in. Putting up a box is interfering with nature. With that intervention comes responsibility.
Nicholas A. Zbiciak, Bluebird_L, 2000
