Mountain Bluebird Pair's Misguided Nesting Attempt

"Mountain Bluebirds are taking nesting material into a charcoal grill. Would you be able to bring a box up this morning for a better nest site?" Susan Spaulding, wildlife tech, was surveying birds at Betasso Preserve when she called us at 7 AM Fri. May 15. She knew we were headed up to monitor our trail. The grill was too flat for a proper nest and likely to be wanted for grilling during the weekend. Also, of the 20 boxes at Betasso, only one had a MOBL nest. All the others were Western Bluebirds (WEBL) or not yet committed.

We brought up a box, labeled it #21, and installed it on a nearby tree. In the picture below, the grill cleanout door is still open, and the new box is visible in the background. The next step was to close the door and hope that the MOBLs would shift over to the new box. However, within a very few minutes, the new box was inspected by both WEBLs and Violet-green Swallows as well as the MOBL male. We decided that we would bring up yet another box the next day. Two days later, Marti was thrilled to find 1/2" of grass in #22 and saw a female MOBL enter the box with nesting material.

The bluebirds kept trying to add more nesting material to the grill, as shown above shortly after mounting the new box and closing the small grill door. They were slow to give up on nesting in the grill. The photo below was taken when we added box 22 the next day, Saturday, May 16.

Below Right - Female MOBL on Box 22 on May 20.
Below Left - Completed nest Box 22 on May 22.

June 13 (2 days old)

June 22 - Two beaks near top, one bottom left.