Wild Bird Wednesday: House Wars

I came by box 14A  on my way back from surveying the 51 mountain bluebird boxes we have on a bluebird trail at Red Rock Lakes and had to stop and watch the action.  A mountain bluebird pair has built their nest but haven't started laying eggs. They were defending the box against four tree swallows.  It was so dramatic, I thought it needed to be presented in a slide show.


I put all my pictures from this fight on Flickr and someone who viewed them wrote me back to tell me that the Tree Swallows need the nest boxes more than do the bluebirds. AND the bluebirds are bigger and stronger and have been seen dragging tree swallows out of the nest.  For an interesting article by tree swallow researchers, click here.

A few days after this happened, I was driving back with Dick, another volunteer.  I had been helping him remove dead fish eggs from our little hatchery.  If the dead eggs aren't removed, a fungus starts to grow on them and then, when there is enough of the fungus, it can kill living eggs.

We saw two ravens on nest box 13A.  They flew off as we approached and then I saw the top was off the box.  We stopped and I checked inside and only saw a few bits of grass.  I put the top back on and then looked down to see the entire nest sitting empty on the ground.  When I got home, I checked my data for this box.  It had had 6 eggs and the female was sitting on them.  The ravens had opened the box, eaten the eggs, and possibly the female, because, about 40% of the time she will stay on the nest when I open the lid.  If this happens again, I'll have to add screws which will make it much harder to do the surveys.

Replacing the roof - a wire is attached to the top and then the ends fit into holes
in the side of the box

The nest removed by the ravens - by Dick

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Postscript, May 28

The tree swallows are ensconced in the nest box.  But I think the bluebirds who lost this nest, are now in box 15.  I had to put that box up after I got here so  it was a new house to the birds.

Along the Bluebird Trail

One of my first assignments here at Red Rock Lakes NWR, was to take on the bluebird box survey for the this year.

We have about 50 boxes along our south road.  I had to locate all of them and repair, put back up or replace boxes as needed. So my first survey took several days to finish learning where each box is located and get it in working condition.

Bluebird and tree swallow habitat

Last Thursday and Friday afternoons I ran the survey for the second time. I think this is going to be an exciting project for me. Watching the birds operate around the boxes and checking inside the boxes is giving me new insights on the birds and also raised questions.

For instance:

The first day I was out, I stopped to watch a fight over housing. A male mountain bluebird was actively defending his nest box from a pair of swallows who were doing close flybys. In between, he would perch on the door and look into the nest. I spent several minutes trying to get pictures of the interaction going on.  Finally I got a frame with a swallow in it.  Then I noticed that the female had also arrived with nesting material.

Male bluebird defending box from overflying tree swallow, while female builds nest

The second time I ran my route, I noticed a tree swallow sitting on one of the newly mounted boxes singing his heart out while three or four other swallows flew around just overhead. Since males and females are almost identical, I wasn't sure if the flyers were females checking out the male or other males thinking about displacing the singing male. I tried to find out how males attracted females and found the males choose the nest site and then advertise for females.  So that might have been what this male was doing. 

On my first survey, I found the boxes to the west end of the refuge were further along than were the boxes to the east.  And the bluebirds had started nesting before the arrival of the tree swallows.  (But since the tree swallows migrated up here before I did, I'm not exactly when they did arrive.) I think the west side is sunnier because the east has the Centennial Mountains really close and they cast shade, keeping the bugs from moving and thus the birds from feeding, so nesting starts later on the east end. 

  Several of the bluebird nests had up to six eggs on the first survey.

A bluebird nest ready for the female to beginning sitting on the eggs

Many times when I open a nest box, I find the female sitting on the nest. This was true, even if she didn't have enough eggs for me to expect her to be hatching them.  The first week I just put question marks for the number of eggs.  Then I talked to a lady  who has done the survey in previous years. She said to stand clear of the box to give the female a place to escape to, then  rap on the box.  This sometimes worded and sometimes didn't.  I wondered if I could carefully just pick the female off the nest for a quick peak. It worked like a charm.  I usually could not even feel her flinch, as I worked my fingers under her and lifted her out.  Then I could put her back and put the top back on the nest without making her use energy to fly out and back.  I took the picture of this female, then lifted her to count her eggs, before settling her back. 

Little Moma

Not all boxes house bluebirds. Many of them are being used by tree swallows.  This pair lives in Box 19 E.

The parents on the nest box

Inside the nest box - Tree swallow line their nests with found feathers

Same nest three days later 

This moma swallow sat tight for a picture then let me pick her up to count her eggs 

Changes happen fast along the bluebird trail.  On the second survey, I found my first tree swallow eggs and first bluebird nestlings. There were nineteen day-old chicks last Friday in the western group of boxes. Females are just starting to sit on eggs on the east end. I'm in the middle of my third survey and found day old chicks in one of the east boxes.  You can tell them from day zero chicks by their bad hair.  I didn't take pictures of them.

Hatching is happening

And to think I get to follow the lives of the bluebirds, and other bluebird box inhabitants all nesting season! Stay tuned.