Wednesday, May 23, 2012

Como Park Bluebird Trail Update: May 23rd

Post contributed by Sharon, volunteer Bluebird Trail monitor:

      Eight chickadees from one nest and 7 bluebirds from two nests fledged in the past week.  Sadly, when I opened the other chickadee nest box, expecting to find it empty and the birds fledged, I discovered 7 tiny skeletons.  They must have died soon after I checked them two weeks ago; either some tragedy befell both parents, or the parents abandoned the nest.
      There were no signs of the two cowbirds eggs that had been in one of the bluebird nests, nor were there any remains of hatched cowbirds.  Perhaps the parent bluebirds removed the unhatched eggs or smothered hatchlings.  The bluebird parents in the other now empty nest had already built a new nest over the old one, which contained one unviable old egg (probably that extra small one I noted in an earlier post).  I removed the old nest material and unhatched egg from underneath the new nest.
      After removing all the old nesting materials and chickadee guards, there are now three empty boxes available for Round Two of bluebird nesting.  Bluebirds usually nest two or sometimes three times in a season.
Newly hatched bluebirds
Chickadees, about a week old

      Two bluebirds had just hatched in another nest, with one more egg to go.  Another box contains 4 bluebird eggs and 1 cowbird egg—the parent bluebirds defend this nest by divebombing me, a less usual behavior for bluebirds, but very common in tree swallows.  Most bluebird parents exit the nest box as I approach and scold me from a nearby tree.  A third box contains three bluebird eggs.
      There are 8 nearly one-week-old chickadees in another box.
      The tree swallow nest with white feathers in it has about 6 white eggs in it, and aggressive parents defending it, swooping and chattering as I checked.  The other tree swallow nest that last week had 4 white eggs and many plastic wrappers in it, now is empty of eggs and all plastic is gone, but the grassy nesting material remains.  No tree swallows were nearby, but I did hear a house sparrow, and perhaps there is a battle going on that the tree swallows have lost.

To view a live bluebird nestcam visit the Cornell Lab of Ornithology,