The bluebird nest box at the Train Tunnel, which had five nestlings in it last week looks to have four this time around. The inside walls of the box, the nest, and nestlings themselves were wet when I opened the box this Tuesday (4/24/12) and I was a little concerned.
We’ve had several days of cold rain which adds to the negative factors detracting from the birds’ ability to survive. The parents have a more difficult time in finding food to feed the nestlings, and the cold, wet chill creates a greater need in the birds for food to maintain their body temperature and to fuel their growth. I’ll check on them later in the week, although there’s not much that I can do about it.
I counted four birds in the nest where last week I could see five nestlings.
Here’s what the birds looked like last week.
I was wrong about the nest next to Take Off. I had predicted that it would be full of twigs placed there by a House Wren, not so. I still heard a wren singing, as I did last week, off in the woods behind the nest box as I made my rounds Tuesday, but the nest box was empty. At least it didn’t have a wasp nest as it did during the first two nest box inspections!
The Carolina Chickadees that had nested in the box behind the Sailboat Pond are gone. I saw no evidence of foul play so I assume that the birds had all fledged and are now following the parents around the woods learning how to feed themselves.
Last week the Amphimeadow nest box held 6 beautiful blue eggs. It now houses six tiny little chicks!
As with the Amphimeadow nest box, the nest next to the Picnic Dome now has chicks residing within its cedar walls.
And now we come to the nest near Gate 3, the Butterfly House nest box. I had expected these birds to be gone, fledged by now. I was wrong, The parents were bringing in food to the nest so there had to be nestlings inside.
I was hesitant to check this box because of the possibility of premature fledging by the birds. Bluebirds fledge in approximately 18 days. I know from my records that these birds hatched at least 14 days ago. On April 10, when I checked inside the box there were at least three nestlings.
Why does it matter when the birds hatched? If you open the nest box when the birds are nearly ready to fledge, but not actually ready, they may shoot out of the nest box when you go in to have a look. If they leave the box before they’re ready to fly it could mean death, a flightless bird on the ground is easy prey for most any predator, never mind the chilly weather with no siblings to cuddle up with. But I looked inside the box anyway, and I’m glad that I did.
The birds appeared to be well on their way to fledging, but behaved themselves and didn’t attempt to take an early leap out into the real world.
I checked on the birds Wednesday (4/26) and the parents were still bringing in food to them, maybe tomorrow.
In summary, there are now (4/24/12) two empty nest boxes, one has been empty throughout, the other had recently fledged 7 new chickadees to help brighten up gray winter days here at the Museum. There are (as of 4/24/12) 18 nestling Eastern Bluebirds in the four remaining nest boxes.
How about that!!
3 responses to Bluebird Update April 26, 2012
Hmm. If bluebirds appear blue because of the way light is reflected from the structure of the feather, then why is the bluebird’s skin on the wings blue?
I emailed Ken Kernodle (built the nest boxes) and plan on calling him later today. He’s already informed me that he intends to stop by, just don’t know when yet.
Any lack of blue pigment in birds is in the feathers, not the skin, although I don’t know any birds that have blue pigment in their skin. I think that the blue that you’re seeing on the wings is from very small feathers and is a result of refraction. Any blue on the skin would most likely be due to a vein just beneath the skin or a very cold little hatchling.
Awesome update Greg, thanks! I’m trying to send along to the volunteer who built the nesting boxes . . .