Aggressive Bluebird

[Mel]

I’ve found a lot of helpful information here, so now that I have a question I thought I’d register here.

I recently moved from a home surrounded by trees to a home surrounded by open field.
Both homes in North Louisiana z8b.

So…
I put up a bluebird house about 6 weeks ago and immediately got Black Cap Chickadees.
So I went out and bought another bluebird house and placed it 18′ away from the other house. I have bluebird tenants!

I heard babies peeping in the BCCH house about a week ago. Yesterday I noticed both the female and male BB chasing off the BCCH parents and also entering the BCCH house.

Are the BB killing my Chickadee clutch!?!? I still hear them peeping.
Should I add a 1-1/8″ hole guard?

I’m getting mad at the BBs! Those chickadees are so cute and tiny, and I enjoy watching them fly- A lofty, romantic flight style.

[David in Stafford,VA]

Welcome to the Group Mel. There are good people here with a boatload of knowledge about the Bluebirds.

I have never experienced “aggressive” blues as you describe them. I know that they will defend their own nest but have not seen them try to take over another box. The smaller hole guard is a good idea.

I do think that the 18′ separation might be too close for their comfort as blues are territorial. It is probably too late now to move the box but I would think about moving it following the fledging of the young.

Good luck. Keep us posted on the outcome.

David

David
Stafford, VA

[nhhawk6]

Hi, Mel! Welcome!
A 1 1/8″ hole guard on the BCCH nest box should do the trick, as far as BBs entering that box, but nothing is going to prevent the territorial behavior your BBs are demonstrating. I doubt, however, that they will actually harm the BCCH chicks. I am in NH, well behind your nesting season in LA, and my BBs are not even building their nest yet, but they are just as intolerant of the BCCH on my property. My male was pretty tough on a BCCH this morning, who was checking out the nest box he had claimed with his mate. I like the chickadees, but I love my bluebirds, so whatever papa bluebird wants to do to protect his nesting area here in NH is alright by me. :)

Randy
Bedford, New Hampshire

[Mel]

Thanks for the welcome!

Should I add a hole guard now? Or should I wait till after fledged?

It’s a cedar box attached to a 6′ cedar privacy fence. Attach by hand driving screws? Would a power tool be too much noise? Glue?

Depending on how this all turns out, I may just remove it and keep it as a back-up. My backyard is supposed to be a relaxing retreat! I will keep y’all updated.

[nhhawk6]

Not certain you could actually get this wrong, Mel. Add it; don’t add it. Use a hand screwdriver, or a power driver. I think the outcome will be the same: BCCH chicks will be fine, and the BBs will be annoyed the entire time they are there. I also doubt the BCCHs would abandon the nest box full of chicks, due to a brief period of power tool noise. You may want to avoid glue, due to the potential for toxic ingredients in weatherproof glue products, but even that is more theoretical, than practical.

Randy
Bedford, New Hampshire

[Carol – Mid-Mo.]

I have never had actual experience with BCCH but I agree that 18′ if probably too close and thus, the reason for this aggressive behavior. I know 300′ is recommended if you want to have two BB nests at the same time, or at least one box in the front yard and one in the back, so you cannot see them both at the same time. The only box that can be close (even paired) with bluebirds is for TRES. Again this kind of info is on the sialis.org website. I have 4 boxes up and they are all at least 300′ apart, all at different corners of my property. This way I have plenty to keep HOSP busy for trapping, and have had two BB nests at the same time, but quite unusual, and also TRES at the same time as my bluebirds. My theory is like Randy’s, whatever my blues want to do to protect their family, is okay by me.

[dogsandbirds]

Hi Mel and welcome!

First and foremost, the box where the dees are should not be on a privacy fence. A slick baffled pole is way safer for them. No sense asking for trouble!

You can use a 1.25″ hole reducer just fine. The dees will probably like that better. It’s small enough and will only admit a blue head, not blue shoulders. These tiny birds seem to have a hard time succeeding and I think they need all the help they can get.

In all my years of hosting birds I have yet to see EABL tolerate the sight of CACH(which they are BTW, not BCCH) during nesting season. If the boxes were out of sight of each other, you would have a much better chance of them leaving the little dees alone to raise their chicks. I have also seen a male EABL toss the eggs (not the chicks) of a CACH pair because he wanted the box. Your male clearly has his own box but still isn’t interested in having CACH neighbors.

Gin
Atlanta, GA

[Mel]

Thanks for the pep talk, y’all. I was a little emotional, but I got my head in the game now. Go Team Bluebird!

A bit of an update:

I have not put a hole reducer on the CACH house.

Yesterday, after lunch, I spent the rest of sun up doing stuff and things in my yard, and keeping an eye on my EABLs.
I think this male is tending to the CACH babies!?!
He spent all his time grubbing and going into the CACH house, occasionally popping into his own home. The female EABL poked her head in the CACH box a few times but spent most her time flying in and out of her own nest box.
I didn’t see a CACH till late in the day. He showed up twice, briefly, and only got within 25 yards of the CACH house.

Today, so far, I have seen a CACH get chased off by the male EABL. The CACH stayed around longer and maneuvered his way to his house, had opportunities to go in, but he wouldn’t go inside. The CACH babies are still peeping and the EABL still appears to be tending to them, grubbing around and then flying in the CACH box.

Some questions:

About how long do y’all figure it’d take for hatchlings to starve to death?
Do you think maybe the female EABL accidentally laid an egg in the CACH house?
Is it possible that the male EABL is tending to the CACH babies?

[Carol – Mid-Mo.]

Mel, have you not looked inside this box earlier to know what’s there? Sounds like quite a mystery story – no ideas really.

[Mel]

The only looking I’ve done was when I first hung the houses. I saw a finished CACH nest, beautiful mossy nest with downy top- I took pictures of it.

At that time I also took pictures of the EABL nest. They had just started so it was just some bits of straw. I did look later, saw a finished nest, but didn’t take any pictures.

Other than that, I’ve just tapped on the boxes to see if I could hear babies peep.

[Mel]

I just took these pictures of the EABL nest!

I hear more than 1 baby peeping in the CACH house. EABL still tending to them.

[Carol – Mid-Mo.]

Wow, that nest seems awfully tall – maybe just the way picture was taken. This is quite a puzzle – never heard anyone talk about blues tending to another species of bird.

[Mel]

There’s a mesh platform in the bottom, to help protect against blowfly larva, it came with the house. It’s probably 1″ tall or so, maybe that is adding height?

I hope he can provide for 2 families at one time!

I just noticed something in the egg picture I posted. The egg at 3 o’clock looks like there are a couple of pip marks, or possible predator marks.

[Lisa]

Darling babies! I miss mine terribly. They are building again though. Yay! Agreed, that is a super tall BB nest! it seems awfully close to predators!

[Lisa]

That definitely looks like a pip mark. Not a predator mark! breathe easy ;)

[Author]

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