Purple Martin
Housing
This is probably one of the most important sections to
the hobby, what type of housing do we want to use for our
martins? There are a large number of choices to pick from and
in reality, it's our own personal preference as to what type to
use. There's commercially manufactured houses of all sorts to
choose from. Aluminum houses, plastic houses, wooden houses
and both plastic and natural gourds. Below, we'll investigate
each in detail so that a newcomer to the hobby can make an informed
decision as to what type he or she would like to use. For the
most part, it will be assumed that we are starting out with nothing
and creating a site from scratch. However, if you already have
an established site that doesn't match these specifications or maybe
you're thinking about making a change, then by all means, read on
and see if there's something here that catches your eye. I
would then suggest your making the update at the earliest possible
opportunity, or at least before the return of the martins.
First, let's look at a few things before we start digging
holes and erecting poles for our houses.
First decision... To start a purple martin
colony.
Now that you've made the decision to start a colony, you
want to do it in such a way that you'll enjoy what you're doing and
there are a number of factors that have to be thought out before we
begin.
First, be forewarned. We are dealing with nature
and wild creatures, therefore, you 'will' be bothered by pests and
predators. You 'will' have to get at the housing to remove the
pests and clean out their nests
Second, you 'should' perform nest checks. Recent
studies have shown that they have become a very important part of
keeping martins.
And third, there is always some general maintenance
that's required from time to time. If you have to climb ladders or
work with difficult housing to do these things, then it won't be any
fun and therefore, you won't enjoy yourself or the hobby.
Hobbies are supposed to be fun, that's why we do them.
Regardless of what type of housing you desire, it should
be easily accessible. You want to be able to easily perform
your maintenance. This one point is very important in making
the hobby enjoyable. Your housing should be easily accessible by
vertically raising and lowering on a pole. This can be either a
pulley system or a telescoping pole system depending on the type of
housing you have. This makes maintenance very quick and easy,
something that is desirable when the martins are in the site. Going
out of your way to properly erect your site to begin with will make
life a lot easier and more enjoyable for you in future years.
If you presently have an established site that doesn't have these
features, then you should by all means, update your equipment so
that it does.
Also, NEVER use housing that TILTS on a
pole to gain access to the house. This could damage the eggs or harm
the young when the unit is tilted to get into them.
Second decision... what type of housing to
use?
Now the decision has to be made as to what type of
housing to use. Each has its own merits, but we as humans all
see things differently, so the type of housing to be used is of our
own accord. The reason you need to decide on the type of
housing first is it's a factor in choosing the type of pole you'll
be using. If it's not a telescoping pole, then you'll need a
pulley system of some sort for the top of the pole you'll be
erecting.
Ask yourself these questions.
Is the housing light or heavy?
Will I need a winch or will a simple rope and pulley
system work?
Each has a different mechanism to lift it and this needs
to be decided first.
Sturdiness
I am a strong advocate of using steel poles that are
plenty strong enough to handle the housing I use. I also
strongly recommend using ground sockets to hold these metal poles in
place. That way, should anything ever go wrong, the main pole
can always be lifted out of the ground socket, repaired and then
replaced in the ground socket. Most people just dig a hole and
bury the pipe right in the concrete and that's not the way to do
it. Once set up, they have all kinds of difficulty getting to
the top of their poles when anything goes wrong whereas, had they
used a ground socket to begin with, all they would have to do is
lift the pole out, fix the problem and then return it to the
socket.
Without going into a lot of the technical garb, the
pipes I use are 1-1/2" welded steel pipe. (1.900"
O.D., 1.610" I.D., schedule 40. The schedule 40 refers to the
wall thickness of the pipe). These usually come in 18 to 20
foot lengths and you can either have it cut to the length you desire
or you could even cut it yourself. Without going thru all the
calculations here, mine have gone thru 50 mile an hour winds without
any ill effect on them at all. I get them home and lay them on
a couple of saw horses and easily work them to what I want.
While I'm at the pipe store, I also get me a 30 inch long
piece of ground socket. The ground socket is nothing
more than a 30" long piece of 2" welded steel pipe.
(2.375" O.D., 2.067" I.D., schedule 40). The main pipe easily
fits down into this pipe and makes for easy removal should it ever
be required.
The only thing you need to do on the ground socket is
drill a clearance hole for a 3/8" diameter bolt 3" up from the
bottom. A 7/16" (.440") hole will do just fine. Then,
put a 3/8 x 2 1/2" long bolt through it and put a nut on it.
This bolt is what the main pipe sits on when in place. Nothing
special has to be done to it because the ground socket is going to
be concreted in place and the bolt will never come out. The
main pole has a " V " notch cut in the bottom of it so it will sit
down over the bolt and the notch prevents any twisting of the main
pole. Hopefully the pictures below will describe all this
clearly.
Third decision... Where to place the place the
pole?
Now comes a very important decision. Where to place
your pole? This should be given a considerable amount of
thought because of all the rules that need to be followed to attract
martins. If you're not already familiar with the tips to
attract martins, then please read them first before digging any
holes. Then, make your decision.
Some Tips to
attract Purple Martins
Once you decide where you want your housing to be
located, using post hole diggers or a small shovel, dig a hole just
deep enough so that the top of the ground socked is level with the
ground. I like to dig mine a little deeper and then add a
couple inches of crushed stone in the bottom. This allows any
rain that might accumulate to drain away. It also allows me to
adjust the height of my ground socket to the correct height by
either adding or removing stones. Once the socket is
positioned correctly, fill the hole to within 3" of the top with dry
Sacrete, (or any concrete mix) making sure the socket is straight up
and down. I only fill mine to within 3" of the top because I
then put dirt on top of it so the grass will grow around my
socket. Then, leave it set for a day. The moisture from
the ground hardens the concrete quickly and is just as strong were
it poured in wet.
One reason for having the top of the ground socket level
with the ground is that, if you ever decide to change locations, all
you have to do is make another ground socket and bury it. The
old one can stay where it is and no one will ever know. It's much
more work to dig up an old ground socket than to build a new one and
the cost for a new one isn't that much.
Also, if you take your housing down for the off seasons,
you can mow and rake and do any lawn work without a pole sticking up
out of the ground. Just don't lose track of it. Grass
can quickly grow over one and it makes it pretty hard to find each
spring.
Housing type
Since you've already decided the type of housing you're
going to use, the top of the pipe has to be worked
accordingly. If you decided on heavy housing and require a
winch, the following picture will show you one idea of how to add a
pulley at the top of your pipe for use with a winch. The
pulley is sandwiched between two safety bracket that are attached to
the pipe. This will give you the best forces on your
cable. The straps over the top of the pole acts as a safety
strap. Should your cable come out of the pulley groove for any
reason, the strap prevents it from falling off the pipe and allowing
your house to come down on you. Remember, we need to be safe
as well as have fun.
Also, remember, NEVER use a ROPE with any
kind of WINCH. Ropes just aren't strong enough to use
with winches and will break easily. Always use a steel cable
made to fit the winch.
Of course, in order to use this with heavy housing,
you'll have to also add a winch to your pipe. The house has to
have a hole in the middle of it for the pipe and cables to pass
through it. The cable hooks to the winch, passes up over the
pulley in the pipe and then goes back down to the house and is
secured there. Then, when you crank on the winch, the house is
moved up the pole.
Weight...
If you weigh your house when it's empty, you can add
another pound for each compartment. Some houses could increase
by 20% to 30% to their original weight and those numbers are a good
approximation as to what you'll be dealing with when it's
full. Most people forget that weight increases when the
housing becomes occupied. That cute little aluminum house that
is so light according to the manufacturer suddenly becomes a lot
heavier than you remember it being in the store. All the extra
weight of the martins and their nesting materials have to be
considered. This is one reason telescoping poles become
difficult to work with, and especially for someone who is slight in
stature, this could become a problem.
Now, let's look at a drawing of a pulley system that will
lift things like gourd racks and lighter houses. This is a
simple design to make and I use this system on my racks and it works
very well.
All I do is buy a 4 inch aluminum turnbuckle,
(3/8" threads), cut it in half, drill a clearance hole for a 1/4 -
20 bolt.
Then, I purchase a couple of good strong pulleys.
These are distributed by National.
I then put the pulley in the yoke of the 1/2 turnbuckle
with the 1/4 - 20 bolt as shown above.
I drill a clearance hole for a 7/16 inch bolt in the top
of the pipe and pass the end of the turnbuckle through the hole and
screw the turnbuckle into place. It really works good and is
plenty strong enough to hole a full rack of 24 gourds. I use a
5/16" diameter braided rope which I get at K-mart to go with the
system. The larger the rope, the easier it is to handle,
especially if you have older and larger hands like I do. And
of course, the larger rope makes the entire system more secure.
Aluminum Housing
Probably one of the first encounters we have with
aluminum martin houses is when we run across them in a store or see
them setting on top of poles in other people's back yards as we
drive around. The average person thinks, "what cute little
bird houses". Unfortunately, those thoughts are correct,
"cute" and "little". Remember one thing. Most aluminum houses
are made and sold by manufacturers to make money. Therefore, they
are engineered to be manufactured for the least investment possible
so the manufacturer can make as much profit as possible. In most
cases, I don't believe the martins' best interests are fully taken
into consideration since most martin houses are built with small
compartments. If they were concerned about the martins, these
small compartments would be enlarged to fit the birds' requirements
and have more room to raise their broods. Adult purple martins
are 8" long. The compartment in most of these commercial
aluminum houses are only 6 x 6 x 6, a full 2 inches smaller than the
adult birds. Yet, the manufacturer says that they are plenty
big enough for the birds to raise a brood. I'm sorry, but I
feel this is very incorrect. Although the birds will use them
it's usually because there isn't anything more suitable around and 9
times out of 10, the broods only consist of 2 or 3 young, hardly
enough to overcome the natural decline of the species. Recent
testing has shown that in larger 6 x 6 x 12 compartments, the
averages are between 4 and 6 young with 7 being very common.
The better houses have the ability to remove a middle panel and make
the compartments a full 6 inches deeper or are designed from the
start for the larger compartments. This gives the birds much more
room to raise their broods and also offers much more protection if a
flying predator just happens by.
Materials
When you first pick up an aluminum house, you immediately
realize how light it is. That's because the material used to
make them is very thin. Also, I feel the thin material is not
very strong when a flying predator such as a Great Horned Owl comes
to visit. These birds are very big and strong enough to
literally pull the front doors to these houses off when they want to
get at the occupants inside. My own experiences were not good
and I personally would not subject my martins to the dangers of
being torn out of their houses by these predators. However, if
an aluminum house is used, a properly designed owl guard should be
installed.
Thermals
Since I work in the engineering field, I know that
aluminum can dissipate heat very well. I also know that it can
absorb heat from direct sun just as well. Although I have not done
any tests on the subject as far as aluminum birdhouses are
concerned, the experts say that it works very well. I have no first
hand knowledge about them other than comments from other landlords
that have them, and they say they work well if you can get the
martins to nest in them.
Pests
I've seen statements from aluminum housing
manufacturers that state starlings shy away from the bright insides
of aluminum houses, however, that's not what I've personally
witnessed. I've also seen English house sparrows literally infest an
aluminum martin house. The small compartments are just the right
size, just the right height and dry. My own personal conclusion is
this. Starlings and sparrows will invade ANY type of martin
housing regardless of what it is. Wood, aluminum, plastic and
gourds. All are susceptible to these pests, and once they take
up residence, the only way to get rid of them is to trap and destroy
them or shoot them. They just will not give up a nesting
cavity once they occupy it.
Cost
Another point about aluminum, the cost. One of these
aluminum houses can be rather pricey. Aluminum, as a material, is
very expensive, but will last out in the elements for a very long
time, therefore, it's a great material for outside use such as
martin houses. If you plan to buy one, the only question here is,
can you afford one.
But do they work?
Yes, they do. Martins do return to them each spring
and if taken care of by the landlord, then they will be used year
after year. However, many people have this thought that if
they just buy the house and put it up, the martins will come and
everything will be O.K. I'm afraid to say that nothing could
be further from the truth. That just isn't the way it is
anymore. With the introduction of the European Starling and
the English House Sparrow, the landlord has to diligently defend his
martin house or the following will quickly occur.
Above are the results of a house that was put on top of a
pole without the ability to easily get at it. It was left to
its own accord and the house sparrows and starlings quickly moved in
and have now claimed it as their own. They actually pack so
much nesting material into the compartments that the doors literally
burst off. The cute little house quickly becomes a slum house
and does nothing more than propagate the very birds we are trying to
eliminate at tended martin sites. This is another reason that
the housing we choose has to be easily accessible and we as
landlords have to constantly defend it from these pest birds or our
housing could end up looking the same as this. Unfortunately,
the thin material that most of these houses are made of are one of
the problems to begin with. The designs just aren't strong
enough to hold the house together should an event occur.
However, below is a link to a site that has aluminum
houses for sale, aluminum houses that I feel were designed by purple
martin landlords with the martins best interests in mind. They are
called Lone Star purple martin houses and I recommend
checking them out if aluminum is what you're interested in.
Yes, the houses are expensive, but if you look at all the
innovations these houses have, I believe you'll find that they far
out way the disadvantages that the cheaper houses have and also, if
you look at it like this, it might make more sense. If you
purchase one of these houses and it lasts you for years and years,
you could break the cost down to a per year basis. Thus, if
you have the house and it lasts you for as long as 20 years, then
the initial expense doesn't seem so bad now, does it!
Wood Housing
I have a woodshop and I build my martin houses. I make
them from Western Cedar, a very light and weather resistant wood. It
is excellent for building bird houses of all kinds. Because the wood
is porous, it has very good insulating properties from heat or cold,
and the natural resins in the wood make it a good wood to use out in
the elements. I have bird houses that I've built 10 years ago from
it and they are still going strong showing very little wear.
Wooden houses are much heavier than aluminum, but they
have their good features.
One, they can be built to the proper specifications that
are required for adult martins. Unfortunately, most of the
plans we acquire to make them are incorrect themselves and the
results are houses that are not built to the proper specs.
Recent testing has proven that martins need more room than the small
6 x 6 x 6 compartments that are on most plans available today.
Recent testing has found that the minimum correct compartment
dimensions are 6 inches high, 7 inches wide and at least 9 inches
deep with 11 or 12 inches being optimum.
Two, another thing that is a must is the ability to
easily access the house and it should easily raise and lower
vertically on a good sturdy pole. Houses of these types are
not made to work with telescoping poles. They are much too
heavy.
And three, houses should have easy access to the interior
by doors on the front of the house. This enables nest checks,
nest removals and of course, maintenance.
One other thing to note. If you're going to
build your own martin house, or bird house of any kind for that
matter, don't build it out of any kind of wood that isn't suited for
use out in the elements. You'll just be building it again in 5 or 6
years.
Special Note:
Unless you know what you're
doing, be sure and fully investigate lumber that has been
specifically treated for outdoor use when building any type of
structure intended to house any kind of live creature. These lumbers
have special chemicals imbedded in the wood to make it last longer
in the elements, and although not all, some of those
chemicals are poisonous to all living creatures, including humans.
When working with these forms of wood, masks should be used to
protect your lungs from breathing in fumes and fine sawdust
particles from these chemicals. Before using this kind of wood, ask
questions from an expert to make sure you know what you're
dealing with.
Plastic Housing
Plastic houses are another form of commercial housing
that is available for martins. Again, many of them have the
same problems that the commercial aluminum houses have with
compartments that are too small for an adult pair of martins to
raise a full brood of young. Some of them now have the option
of removing a center panel allowing the compartment to be made 12
full inches deep. This is good because the martins need the
extra room, especially if they are backing out of the way of
danger.
If you select one of these houses, check it out first and
make sure that the unit is able to be reworked to the larger
compartments. Also, make sure that it is accessible for nest
checks. This will mean that the front of the house has to be
able to be opened so that the landlord can get in to do the
checks.
And one more thing. Make sure that the house either
has crescent shaped entrance holes or can at least can be changed to
them. They are a very important factor in the war against the
European starling.
Plastic Gourds
In recent years, there have been a few innovations in
plastic gourds that are changing the martin keeping hobby.
Originally, there were a number of small 6" gourds that were on the
market, but it was quickly discovered that these gourds were much
too small to be used for martins. Unfortunately, the
manufacturers of these gourds refuse to quit making them, proving
that the bottom line is more important than the martins well
being.
In this chapter, I would like to talk about plastic
gourds whose manufacturers have realized that those little gourds
were too small and began manufacturing gourds that are designed for
the martins. If you think you'd like to try some plastic
gourds, then please make sure you get gourds that are plenty big
enough for the martins.
Today's modern plastic gourds are virtually maintenance
free. Manufactured from white polyethylene, they never need
painting or soaking or any of the common maintenance issues that
naturals require. The are almost waterproof, sun proof and
with the proper crescent entrance holes, starling proof. Let's
look a little closer at a few of them.
This gourd is manufactured by Natureline. It's a
full 10 inches in diameter and has three different front inserts
available. The 2" round hole, the 1 3/16" oval and a blank as
shown. Although not tooled up for crescents yet, a blank can
be ordered and with just a little work, the crescent shaped entrance
hole can be easily cut in. Since it's been shown that
starlings are able to negotiate the oval holes, it's recommended
that the crescents be used over all other holes.
This gourd is known as the SuperGourd and is manufactured
by Bird Abodes in Pennsylvania. This one has an access lid
which makes it very easy to do nest checks and nest
maintenance. I added the crescent insert to this one because
it has a round hole, but they are now available with crescents
molded right in. If these interest you, contact the PMCA
This gourd is unique in the fact that it's offered to the
martins in the horizontal position. As you can see, it also
has the 4" access port and it also has the crescent entrance hole
molded right in. One added feature is the depth. No owl
can reach to the back of this gourd to get at its occupants.
This horizontal gourd is produced by:
The Bird's Paradise'
20835 Morris Rd.
Conneautville, Pa, 16406
(814)-587-3879
Natural Gourds
Finally, let's look at natural gourds. This is another
form of housing that is widely used throughout the martin's range.
They're light, they're cheap, they're just the right size and if
done right, very easy to care for. If, for some reason one becomes
unusable, you simply replace it. You can either paint them or leave
them natural, the martins don't care, although painting them white
is highly recommended and, will not only help attract the martins,
but it will cut down on the heat from the summer sun. Painting
will also make the gourds last longer.
Gourds can be presented to the martins in many different
ways. One method is to string them on a wire stretched between two
poles, but this method makes maintenance very difficult, if not
impossible. Raising and lowering a gourd line requires a
special mechanism and it has to be repeatable so that the gourds
return to the same level every time.
They can also be put on a metal pole with cross
arms. No doubt you've seen the old hay rake times welded to
the top of a pipe or even the old metal wagon wheel. Located
correctly, the martins readily accept any as a nesting site as long
as the gourds are of decent size. The rack you see above is my
own design and, depending on how you build it, can hold anywhere
from 8 to 25 gourds. I can honestly say that the martins love
it. I came up with my own design for a rack because I wasn't
happy with the way the others looked, plus I wanted something that
was easily accessible.
Gourds were used long before houses came onto the scene
and they worked fine then and they still work just fine today. And,
just like any other outdoor item you might have, they will require
occasional maintenance, and/or replacing. Although very hard on the
outside, their inner walls are porous and therefore, do not transfer
heat very well. Also, the softer insides allow for the
martin's claws to dig into the material so they can get a good foot
hold when walking around the inside of the gourd. One other
thing, they sway in the wind and this motion is said to deter other
birds from nesting in them, but I wish someone would tell that to
the other birds. Unfortunately, that's just another of the
myths about the martin hobby that has been passed down through the
generations.
Gourds can be worked to add any style entrance hole you
like plus, you can even add little rain canopies and access holes
for nest checks. The screw on - screw off caps stay put until
you take them off and the birds don't mind them at all.
I happen to like gourds. I like the fact that
no two look alike. Each has its own individual aesthetic
appeal. Plus, the martins love them. They like them so
much in fact that, if you presently have a martin house and still
have not attracted martins, you might want to try hanging 4 or 5
large gourds from the bottom of it and see what happens. If nothing
else, the gourds will attract them to your house and if they do
happen to fill the gourds, they'll soon be overflowing into the
house too.
If gourds interest you, then here is a link to a page
that will show you just how to work gourds so that they become
'martin magnets'.
Gourds to
birdhouses
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Woodside Gardens
The Registry of Nature Habitats
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