Bluebird Update 4.26.16

At this time last week there were 22 nestlings and 5 unhatched eggs in our six bluebird nest boxes. That’s 10 bluebird nestlings, 12 chickadee nestlings, and 5 unhatched bluebird eggs.

The 5 bluebird eggs have since hatched, but we now have fewer nestlings than we did last week. We currently have 21 nestlings. How can that be?

One of the chickadee nests was emptied of its inhabitants. Predator! This, despite the fact that all of the nest boxes have predator guards installed. A snake is suspect. I’m afraid there was an oversight by the predator guard installer, me. More on that later, read on.

The Cow Pasture nest is doing well, it has 5 healthy bluebird nestlings. They may still be in the nest by next week’s inspection since fledging takes place between 16-21 days after hatching. I’m not sure exactly what day the bluebirds in this nest hatched but it was sometime between April 12 and 18, so they may need more time to grow. Their eyes have yet to open and their feathers surely need more time to grow.

Cow Pasture nest with five bluebird nestlings (4/26/16).
Cow Pasture nest with five bluebird nestlings (4/26/16).

The six chickadee nestlings in the nest next to the Bungee (Take Off) look to be ready to go. Their plumage looks to be near complete, their eyes are wide open and they appear anxious. They will most surely fledge sometime this coming week.

The Bungee chickadees are just about ready to fledge (4/26/16).
The Bungee chickadees are just about ready to fledge (4/26/16).

There are signs of new life in the Sailboat Pond nest. This nest was started by chickadees but I later found a broken egg inside the nest and ants and a bumble bee had taken possession of the box. Today, there were a few surprises as I approached the nest box. Besides the Canada geese grazing on the front lawn of the bird house, a red-shouldered hawk was perched atop the box.

Geese grazing in the grass and hawk atop the nest box (4/26/16).
Geese grazing in the grass and hawk atop the nest box (4/26/16).
Red-shouldered hawk atop Sailboat Pond nest box (4/26/16).
Red-shouldered hawk atop Sailboat Pond nest box (4/26/16).

The hawk soon departed, I shooed away the geese and peeked into the box. The handful of twigs in the berry basket inside the box hints at a house wren’s intentions.

A sure sign of house wren activity at Sailboat Pond (4/26/16).
A sure sign of house wren activity at Sailboat Pond (4/26/16).

I had peeked into the nest at the Amphimeadow on Thursday of the previous week in order to show a colleague the nest. Just a few days prior it had been packed with six freshly hatched chickadees. By Thursday, it had been cleaned out. The chickadee nestlings that had been in the nest were gone. No disturbance of the nest material could be seen, but the chickadees were nowhere in sight.

I

An empty nest at Amphimeadow (4/26/16).
An empty nest at Amphimeadow (4/26/16).

 

The removal of the occupants of the nest, with little or no otherwise disturbance, indicates to me that a snake was involved. After looking over the scene I could see that I had left a gap, however small, between the predator guard and the pole it was mounted on. In my haste to install the guard I had overlooked this gap (only about 3/8”), inviting a snake to squeeze past the guard and into the nest. It has since been corrected.

Amphimeadow nest box with predator guard.
Amphimeadow nest box with predator guard.
Gap between pole and guard.
Gap between pole and guard.

I was greeted by the male bluebird as I neared the Woodland nest. He watched as I walked up to the nest box and both he and his mate dive-bombed me as I peered into the nest. I quickly took a photo and closed the box, leaving them and their five nestlings in peace.

Watching me approach the nest (4/26/16).
Watching me approach the nest (4/26/16).
A tightly huddled mass of bluebird nestlings at Woodlands (4/26/16).
A tightly huddled mass of bluebird nestlings at Woodlands (4/26/16).

The last nest on the trail is the Butterfly House nest. On 4/19 there were five bluebird eggs in the nest. Today (4/26) there are five bluebird nestlings.

Butterfly House nest (4/26/16).
Butterfly House nest (4/26/16).

So, we now have 15 bluebird nestlings at the Cow Pasture, Woodland, and Butterfly House, with 5 nestlings each. There are 6 chickadee nestlings at the Bungee nest. We lost 6 chickadees at the Amphimeadow nest due to predation. And, a house wren has shown at least partial interest in building a nest at the Sailboat Pond nest box.

What will happen next?

For the answer to that question we’ll have to wait till next week.

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