The HOSP goes into the nestbox because it wants to nest in there too or because they are nesting close by and don't want another bird nesting in the box. You are lucky no bird was hurt last year as most of the time if HOSP are left to nest in boxes they can and will kill other cavity nesting birds. It is good to use HOSP control if you want Bluebirds nesting safely in your nestboxes. Visit sialis.org to learn more about safely having Blues nest in your yard.

Donna

Perfect time for an inbox trap. Can't say enough about the VanErt traps-marvelous devices!

Easier now to trap and dispose of the HOSP-until you do, you risk the heartbreak of losing your other birds. The HOSP will NOT give up the box. As much as you may feel the blues can defend the box, that false sense of security can cost you dearly. Those HOSP are devil birds and do not deserve to nest.

I cannot tell you how many people I have met, who hosted bluebirds successfully the first year, only to have them killed by HOSP in the second year. Hey, I'm one of them! Most people are just not aware of the HOSP danger.
It might be that the HOSP have nested nearby, have seen the successfully used nest cavity, and become emboldened, as well as the fact that THEIR many young now need additional nest sites. HOSP claim nest sites earlier than other birds, multiply MUCH faster than other birds, and are much more aggressive than other birds. That's why they are called "invasive species." Even when they do not kill other birds, they outcompete them for nest sites.
It is heartbreaking to find a mother bluebird dead on her nest, protecting her eggs or young. Or to open the nestbox expecting to see newly-hatched babies, helpless and naked, only to find them hatched but their heads pecked in by HOSP, or the eggs smashed. One memory is burned into my brain forever - as I watched a young male bluebird enter an empty nestbox for the first time to investigate a potential home, he was followed in by a male HOSP. Within seconds, I ran out to chase the HOSP, but it was already too late. That beautiful bluebird was fatally injured, but I will not describe it. He took his last breaths in my hands as I sat on the ground with him, and his brilliant blue feathers, gleaming in the morning sunshine, would brighten the skies no more. That particular HOSP returned later, thinking he had claimed a home, but he met me instead.
BlueBars

Here is a link that might be useful: Impact of invasive bird species

Button20...Please take their advice. When I joined this forum in Jan. '07, I didn't even know what a HOSP was, much less, the destruction they cause. Luckily, I had two successful nestings. Then, back in early fall, I spotted HOSPS for the first time HERE and my heart sank! Long story short, they have totally disappeared, but I am constantly on guard. This forum alerted me to the dangers facing cavity nesters, and how we can best provide a safe environment for them. If there is one little piece of advice I remember the most, it's either manage the HOSPS, or take down nestboxes all together, and hope the blues will be safe elsewhere. Good luck!

Donna

I've been sniping hosps off with a low powered bb gun. Been averaging about one a week. That seems to be about how long it takes for another one to claim the box.
I did finally buy some mylar strips at a party supply store. Going to try and see if that discourages the hosps.

Button20- it's just a matter of time before eggs, nestlings or adult birds are lost to HOSP.

Neopyte, try a sparrow spooker AFTER the bluebird (or other native bird) lays the first egg. instructions at http://www.sialis.org/sparrowspooker.htm

For graphic photos and stories of what happens when HOSP are left alone to do what comes naturally to them, see http://www.sialis.org/hospattacks.htm

Here is a link that might be useful: methods (passive and aggressive) of controlling HOSP

Button, you can spend hours and hours researching on the sialis site but unless you actively pursue HOSP control it will do no good. All the information out there can truly humble a person and it may seem like overkill, but it is totally necessary. Take it from Bet-my hero.

My HOSP and EUST will meet a MUCH greater threat this year because of what I learned last year. Besides being able to build a decent birdhouse, I'm not a bad shot either. (The EUST are on my hit list because of the threat to my woodpeckers).

For a woman of 58, that ain't half bad.

Linda

I just noticed two male HOSP taking a strong interest in my new BB box this morning (central IL). I don't think one has claimed it yet, they didn't seem to mind the other male being present. Both were sticking thier heads into the hole at the same time. I will test out my new Van Ert in the coming days. I'm also going to reactivate my DRST. I had pretty good control over the winter, but it appears a new flock is in the neighborhood.

Im also surprised the HOSP show a large interest in my new big box. I was hoping to get a N. Flicker or a screech Owl to move into it. I figured EUST would be an issue with it (already saw one peeking into it) but didn't think HOSP would be a problem. Its high enough in the tree a big Van Ert wouldn't be convenient. I'll probably use a BB gun to control the undesireables. Hopefully, an Owl will find it and get a house along with a house warming snack.

Thanks bet. I didn't know that.
But right now, some other bird has started building a nest in it. Don't know what it is. Smaller than BBs or hosps. Black head, off white throat. Extremely fast. I've only seen its head sticking out of the box. When he takes off, his body is just a blur.
In any case, I'm sure its native, and I ain't shootin it.

Neopyte, sounds like you have a chickadee building. You may want to add a 1/8 inch hole reducer so the HOSP can't harm the chickadee.

Donna

The Dees are wonderful little houseguests and you will enjoy watching these delightful birds from nestbuilding to fledging! They checked out my BB house last season, but the blues won out...that was just as exciting. I know they nested close by somewhere, because they brought the fledglings to the feeders, and I still have 4 or 5 at my feeders daily.

Donna

Cool! Although I do so enjoy the bluebirds, I'm sure I'll learn to love the chickadees.
dzyg, where/how does one acquire/fabricate an "1/8 inch hole spacer?
And their preferred feed?
Presently, my bb box is aimed at a feeder about 6 yards away, for fledgling bb's to land their first flight.
Will that be ok for the chicadees too?

Neopyte, I had my dh make my hole reducers, he has a drill press?? at work and used cedar. However I know you can purchase them also, hopefully someone else here will chime in with the where on that one. I had chickadees building last year but was a day late on the hole reducer, the HOPS ran them off. The box they had chosen wasn't one I could put a van ert in and I didn't, at the time, have a spare nestbox to use as a trapbox. Luckily the dees didn't get harmed but I was sad to see them not nest there, coincindentally the Blues ended up nesting in that same box, by that time the HOSP had either been eliminated or left the yard. They usually say to not put the reducer on until the chickadee lays the first egg as they don't care for the 1/8 hole as much but can get into it fine. If you have HOSP around though, I would do it before and hope for the best. Better to be safe than sorry. As far as seed the chickadees love sunflower seeds, hearts and chip or BOSS, the also like peanuts and suet around here.

Also it isn't a good idea to put a nestbox near the birdfeeders, too much bird traffic that way. The closest nestbox I have to a feeder is about 50ft, the rest are much further away than that. It is best to point the hole of the nestbox away from prevailing winds, preferabbly towards a tree but away from the way the direction the rain usually blows during the summer months.

Donna

Thanks for the tips Donna. I'll move my feeder. And as far as the wind and rain, I'm ok there. And I have a drill press, so I can make the reducer. I'm assuming that I'll be reducing the hole by 1/8", which means a wall thickness of 1/16" on the spacer. No prob.

Ok neopyte, I am not mechanically inclined so I am not even sure if it is a drill press that he uses. LOL! Not sure I follow you on the thickness of the reducer. A hole reducer is a piece of wood that goes over the existing hole and is screwed on from the outside. Here is a photo I have of one we put on one of the houses when a woodpecker enlarged the hole on our bluebird house. Note it is a swallow peeking out. A normal bluebird house has a 1/2 inch hole so the reducer makes it go from the 1/2 to the 1/8 inch, the piece of wood just needs to be bigger than the hole by the amount of room you would need to screw it to the box, not sure that the thickness of the wood makes a difference as long as the screws don't poke into the inside of the box. I hope I am making sense here. LOL! This is kinda a close up photo but you can see the piece of wood added to the front, it is larger than it needs to be really.

Donna

Actually, the purpose of the "hole reducer" or "hole guard" is to make the entrance hole smaller in diameter. On Bet's web page on chickadees, she provides information about the how's, why's and size: To prevent HOSP entry, use smaller than 1.25 inches (round diameter). There is a link you can click to find sources to purchase them, and suggestions how you can make your own. For example:
"You can install a 1.125" hole guard to keep House Sparrows and other larger birds out after the chickadee starts to build a nest, preferably after the first egg is laid to ensure that they have bonded to the box. I have never had a BCCH abandon a nestbox after a hole restrictor is put on if I wait until an egg(s) is laid..."
There is a lot more information at the link below.
Best of luck with your chickadees!!!!!! Wonderful little birds.
BlueBars

Here is a link that might be useful: http://www.sialis.org/chickadee.htm

You could use a forstner bit, a spade bit or a door knob hole cutter to cut any size hole you need into a square block of wood. Double protection because it would make the hole deeper for some starling protection and reduce the hole size on any box to keep out the HOSP.

My killer HOSP avoided the Gilbertson PVC boxes that held my precious dees. This year, the boxes will be spookered, just in case.

Neopyte,
Make 100% sure the bird that is building its nest in your box is a chickadee before installing the hole reducer.I wait until I know eggs have been laid before installing,Chickadees will cover their eggs,don't poke around in the nest.Is the nesting material green moss?,if it is then it is a good chance it is a Chickadee.Titmice will also use moss,I sometimes have trouble identifying the nest in the beginning stage.Keep us posted.

Good luck,
Matt
Baltimore MD

OMG I just realized I have been saying 1/8 inch hole, gosh no bird is going to get in a hole that small!! I meant
1 1/8 inches, normal bluebirds houses have 1 1/2 inch holes not 1/2! Yikes, I did know what I was talking about but sure made this confusing. The nestbox pic I posted had a 1 1/2 inch reducer added onto the nestbox because the woodpeckers enlarged the hole to about 2 inches and I didn't want any starlings getting in there. Sorry about my bad brain to hand typing!!

Donna

I like to put the hole reducer on the INSIDE of the panel (so the outside hole looks bigger to the chickadee.) Chickadees are very secretive when nesting.

DEFINITELY put the restrictor up ASAP so the HOSP don't kill the chickadees or take over the box.

dzyg, I'm a machinist, and I work with engineers who do the same thing sometimes, so don't worry about it.
But that doesn't stop me from teasing them about it. :-)
I'll go ahead and make a 3/4" thick spacer block with a 1.125" hole in it, and make it easy to install and remove.

Anyway, as I said in another thread, the chickadee has left and now I have BB's checking out the box. They haven't started building a nest yet, so I'm trying to encourage them. I've had a few times where the BBs preferred pine needles to make their nest. But the nearest pine trees are a quarter mile away. So just in case, I went down to the pines and brought back a bag full of dry pine needles and scattered them across my yard.

Funny thing, its only been a few days, but since the BBs have showed up, I haven't seen a single hosp.
Knock on wood.