Pests and Predators


Purple Martins



Operating a purple martin colony is a very pleasant and self gratifying hobby. Few things are more soothing or relaxing than sitting out on the back deck in the evening and watching the superb aerial acrobatics of these delightful birds. They have a way a making a late afternoon breeze a thing of magic and their constant chatter keeps things lively around the site.  Likewise, at times, it can also be very exasperating due to having to deal with some of the pests and predators that bother them. However, if we plan to dip our hand into taking part of nature this close, then we're going to run into some of these problems.  This page will make an attempt to deal with two of problems.


Before we get into controlling these pests, may I interject something here:

I've been asked time and again, how can I feel so strong about keeping and raising one bird species and yet, advocating the capture and destruction of another.  The reasons follow:


BOTH of the species described on this page are exotics, (birds not native to this country, but instead, introduced to this country by man).

BOTH of these species will kill other birds simply for the sake of killing.

BOTH of these species are becoming so large in numbers, that they are actually harming our own native cavity nesting birds.

BOTH of these species are a major problem for humans in the fact that millions of dollars of food are destroyed every year by these pests.  Midwestern stockyards and granaries are constantly at odds with these pests, ultimately costing the rest of us more money for our beef and cereals.


Let me also state, I have as great a respect for nature as anyone else, and under normal circumstances, I will usually let things happen as nature intended. I don't kill snakes simply because they're snakes and I don't shoot coyotes simply because they're coyotes. But this starling/sparrow problem is one situation I feel needs some serious intervention by man to help in controlling these pests. European Starlings and English House Sparrows have become a major problem to the other native birds of this country and since their introduction into the U.S. they have propagated to the point that they have become the worst bird pests in this country.  They can raise multiple clutches of young per year, and our native birds just can't compete with them, especially the migratory ones that raise only one brood per year. These transplants are aggressive birds and will literally take over any available nest site. Once they've obtained possession, they zealously defend them at all costs, thus shutting out the possibility of any other native cavity nesting birds from nesting. In and around a colony site or bluebird trail, I feel that capture and destroying them is the only sure method of control. Once captured, the method of disposing of them is up to you.  If you are not able to dispose of these two pests, then I suggest you not get into the martin hobby.  By not tending your housing and allowing the pests to nest, you'll only be helping them out and believe me, they don't need any help at all.


Once you put your housing up, either starlings or house sparrows are probably going to be the first birds that find it. Because of their nature, they can quickly become a major problem around any martin site, especially if it isn't well established. They bother the martins by continually running them off and if the martins do get to lay eggs, both of these birds will go from compartment to compartment, destroying the eggs and young and taking over the nesting cavities. It doesn't matter what type of housing you have, if a starling or sparrow decides it wants to nest in it, it will. Different areas of the country are bothered differently by these pests.  Some places have very few, if any at all while others, like here in Northern Alabama where I live, it is inundated with these pests to the point that they have practically driven the other cavity native birds out of the area. The following are some details on them and my thoughts and comments as to the control of these two bird species.


And so that you don't think that I am the only one that feels this way, under each bird's bio, I give a few links to other sites that will reinforce my statements.  Take a minute and read those too.



European Starling (Sturnus vulgaris)

Nickname: Needle Beak


Migration Status:  Short distance migrant

Breeding Habitat:  Urban

Nest Location:  Mid-story/usually 10' and above

Nest Type:  Cavity

Clutch Size:  4-7

Length of Incubation: 12-14 days

Days to Fledge: 18-21

Number of Broods:  2, occasionally 3

Diet: Mostly insects, but to a lesser degree, fruits and seeds


Other links:



Or do a Google search on European Starling


History of how they got here:


Late in the 1800's, the starling was introduced to this country.  A man named Eugene Schefflin is the main name that comes up when doing an investigation as to why they are here.  Schefflin was head of a group of apparent nuts about Shakespeare.  Being very 'well to do' these folks could afford it, so they had 60 pairs each of all the birds that were mentioned in the plays of Shakespeare shipped here to America from Europe.  They were then released in Central Park in NYC.  Not knowing much about the different birds or their life styles and requirements, all eventually perished 'except' the European Starling.  Having no natural enemies and now, with all the new and unlimited opportunities to nest, they propagated and flourished and from that time until today, this species has spread out across the U.S.  Starlings are cavity nesting birds and because they have propagated unchecked for all these years, their numbers have grown into the 100's of millions and they are now a very big problem in this country, especially in the cities.  In fact, with their being able to adapt to just about anywhere and raising 3 and 4 broods a year, the starling has now become one of the most populous bird in America today.  Long ago, starlings adapted to living next to man and his dwellings and find plenty of nesting cavities that suite their needs rather nicely.  Likewise, because of their nesting habits and their very high numbers, they have devastated our own 'native' cavity nesting bird species.  Because of their very aggressive nature, starlings are a threat to any cavity nesting bird they can 'trap' in their nests. 


Many of our native cavity nesting species such as Woodpeckers, Tree Swallows, Wrens, Chickadees, Titmice, Bluebirds and Purple Martins, have suffered greatly because of these two invasive pests. All of them use cavities to nest and if the cavities aren't available, then they can't raise their own broods.  Martins, being totally dependent on man for their housing, are communal nesters and require man-made and supplied condos in which to nest and propagate and because of their nature of having to leave the colony to feed, the starlings often slip into their unguarded nests and do their dirty work, destroying eggs, young and even an occasional adult that happens to become trapped in the cavity.


If you have a martin house and this has happened in your house, then this sight alone is enough to make anyone learn to hate these pests.  Unlike the aggressive starling, martins are a gentle bird species and are no match for a starling in a 'one on one' fight in a closed in cavity.  Once they evict the owners of one compartment and take over, they often slip to adjoining cavities, destroying the eggs and young.  They then settle back to wait on the returning martins and when they eventually return, the starlings will drive them away, preventing them from nesting in the house.  Often times, a single pair of starlings will take over an entire martin house and prevent its use by any other bird.  In fact, I have personally seen where a pair of starlings built their nest right on top of baby martins that weren't even dead yet.  It's not a pretty sight for anyone to see.


Because of their nature of foraging for food, starlings have developed very strong beaks and body muscles and can inflict major damage on adult martins, their young and eggs, and even YOU if you're fortunate enough to get your hands on them and aren't careful how you handle them.  Even though the potential landlord watches and drives them away whenever possible, they will still come back the minute his or her back is turned.  They are very persistent and just will not give up once they decide they want to nest in one of the cavities.

Starling Nest

A starlings nest will fill the nesting cavity more than a martin's nest and they will have a very deep bowl in the back of the compartment with material flowing up the sides of the cavity. Starlings do not use mud to make a dam in the front of their nest like some martins do. This is one of the easiest ways to discern which type of nest you are dealing with.










Starling Eggs

Starling eggs are about the size of a Robin's egg and are powder blue. Usually there are 4 or 5 in the normal nest. These differ greatly from martin eggs which are pure white and a little smaller.

As I stated above, starlings are a very aggressive species of bird, and in close quarters, the martin is no match for them. Their destruction is total and if they can capture a martin in their nest, they will kill the parent and any baby birds by pecking them in the heads. Yes, it does sound bad, and it looks even worse. It is very disheartening to look into a martin's nest and see this shocking picture. Once you've seen it happen to one of your martins, I'm willing to bet you won't have any problem disposing of any starling you can get your hands on.








Fortunately for us, there are a number of different methods to control these pests around our colonies. You can acquire the plans for the a Troyer S&S Controller and build one. Then, carefully following the instructions, set it up near your colony, like under a tree or on the side of a building.  As you can see, it looks just like a small purple martin house. The unit is designed with a self setting trap inside of it.




It works like this.















There is a hole in the front of the unit for the starling to access the unit. Upon entering, the starling trips the trap, (an idea developed by Andrew Troyer, the trap's inventor). The starling is then forced to exit through a hole in the rear of the house and is delivered to a basket near the ground via a tube down the back of the unit.









Here the landlord can access the birds, and again, although this sounds cruel, I strongly suggest destroying them. Relocating them is a waste of time and effort.  Birds have a very good homing instinct and will be back at the site before you.


I once tested this by tying a string to the leg of a starling that I had trapped at my site and then drove it about 7 miles away and let it go.  I'm not kidding when I say it beat me back to the nest site.


Starlings raise three, and sometimes four, broods a year and native migratory birds just can't compete with them.  Their numbers have become so numerous that they can be seen flying in large flocks that literally take 5 and 10 minutes to pass over head.  My own personal feeling is that if some major control method isn't initiated nationally, they will soon wipe out a number of native species of cavity nesting birds in the very near future.

Once you have one of these units set up, all you have to do is keep an eye on the basket and dispose of the starlings whenever one is deposited to the basket. When the bird leaves the trap part of the unit, it automatically resets itself and is ready for another starling.

One other thing. Should a desirable bird happen to trip the trap, all you have to do is open the cage door and let it go, unharmed.



Now, for those that still have problems believing that starlings are a problem, take a look at the link supplied below.  This video was taken by Donna and Simon Gillbee, of Pearland, TX.  It shows quite clearly the aggressive nature of starlings and what they are capable of doing in a martin nest.  If you still think that starlings will get along with martins, then I feel that you need to be doing something else other than keeping martins.  The movie will take a few minutes to play, but it really shows what starlings are like when they enter a purple martin's nest.  Once you get there, click on the start button in the center of the screen.


If you have dial-up, sorry, but you might want to find a high speed connection somewhere.










English House Sparrow  (Passer domesticus)

Nickname:  Flying Rat


Migration Status:  Non-migrant

Breeding Habitat:  Urban

Nest Location:  Just about anywhere

Nest Type:  Cavity

Clutch Size:  4-7

Length of Incubation: 10-12 days

Days to Fledge: 15-17

Number of Broods:  3-5 depending on local

Diet: Mostly seeds, but to a lesser degree, insects


Other Links:



A Bluebirder's Experiences

Nothing But Trouble

Or, you can do a Google search on House Sparrows...


History of how they got here:


There were a number of reasons that the house sparrow was brought to this country. Here are only a couple.


In the mid 1800's the English House Sparrow was brought to this country to try and do something about the insect pests that were waging war with the crops that were being raised at that time.  However, not much thought must have been given to the diets of the sparrow, because if they had, they'd have found out that sparrows eat very few insects.  Sparrows are mainly seed eaters.


Another reason was that the newcomers to this country missed the little birds of their home country, thus, more were brought into this country.


And still another was, during that time, horse droppings were becoming a problem in the cities and these birds were brought here to hopefully clean up some of the grains that passed thru the horse.  And of course, there are more...


At one point, there were actually programs set up to propagate sparrows, however; within only a short time, it was recognized that it was a major mistake to bring these birds to this country and of course, by that time the damage had been done and now, it's too late.

This cute little fellow here is also a wolf in sheep's clothing. He may be cute, but he is also very aggressive and destructive and once he gets situated in one of your martin house (or bluebird) nesting cavities, and although usually a threat to adult martins themselves (not true with bluebirds), these birds will attack the young and eggs (a term called sparrow revenge) and then take over the nesting compartment. If you find a pile of martin (or bluebird) eggs on the ground that have holes in them, then you can bet it's the work of one of these fellows. And if he gets himself established in a nesting compartment, be prepared to tear it out time after time.  They are very determined and persistent and will rebuild as many times as you tear it out.  It's also believed that this is where the 'sparrow revenge' comes into play, but in reality, it's just their aggressive nature.

Sparrow Nest

Sparrows are a member of the weaver finch family and will put anything in their nest that they can.  Hay, grass, roots, weeds and a lot of feathers.  (Feathers are highly prized by sparrows and can often be used as bait to capture them).  In fact, they pack so much material in the cavity that no other bird will enter, not even a starling.  Often, you can see the excess material coming out of the entrance hole and if given enough time, this material will even push the front doors off of some houses.  Once they are settled in, they will go from compartment to compartment, 'pinning' (pecking holes in) any eggs they find in the entire house.  They are very territorial and do this to prevent the raising of other bird species' young so that there is less competition in the future.  Sparrows are voracious nest buildersand will eventually fill all the cavities of the house, making it un-inhabitable by other birds.  So the next time you feed one of these two pest birds a McDonalds French Fry or a piece of bread from a hamburger just remember, by feeding them, you are helping in the destruction of some of our own native bird species.


The aluminum house displayed here shows what can happen when these little pests are left unchecked.  They will clog the compartments with so much nesting material that the doors will no longer stay  attached.  Sorry the photo isn't real clear, but you can faintly make out the male in the upper left hole of this house guarding his compartment.


So, if you think it's OK to let them nest in your martin house, then here's what you should expect to see in your house before too long.






Sparrow Eggs

Sparrow eggs are much smaller than starlings and martins. They are a sandy brown with dark brown specks all over them. There will usually be from 3 to 5 in a normal nest.


















Sparrows are notorious for entering a martin nest when the martins have left to feed and "pinning" the martin eggs as shown here.  This obviously renders the eggs useless and of course they won't hatch.  This cuts down on the number of martins and in turn cuts down on competition for future nesting sites.  They have also been known to kill young that have been left unguarded.


Bluebirder's are plagued by these little vermin and all kinds of devices are constantly being tried to try and keep sparrows out of the bluebird housing.  Some work a little, others don't.









DO NOT believe that these 'cute little birds' are not a threat to other native cavity nesting birds in your area.  Here is a picture of a Bluebird that I found in its' nest with 3 eggs and a sparrow had built its' own nest right on top of it.  The bluebird was pecked to death in its' own cavity while trying to defend its eggs.










Eliminating them:


One of the major discoveries in the last few years to control the starling infestation is the SREH, (Starling Resistant Entrance Hole).  There are a number of different versions now and they work because they are just a little smaller than the height of a starling's sternum and under most testing, 99% of all starlings are kept out of martin housing.


Shown here is a picture of one of my gourds that a starling pair found attractive enough that they tried to get into it for over 2 weeks without success.  As you can see they actually pecked away all the paint trying to enlarge the hole so that they could enter.  This was a gourd that originally had a round 2 inch hole and I changed it to a crescent shaped hole with a simple add-on.  If starlings are a problem around your site, this is one of the first things you should look at.


Starlings hate them.


Not only do SREH's keep out starlings, but they now help keep out other predators as well.  Providing the compartment is deep enough and the martins have a chance to back out of the way, many of the predators that could originally enter or reach into the 2 inch hole, will now be foiled.  Jays can no longer get into the compartments.  Nor can squirrels, (without chewing it bigger), crows, owls, 'coons or gulls.  All are too big to get into the smaller SREH.  If any of these other critters are a potential threat to your colony, then I strongly recommend your changing to SREH's.



Other methods


There are many different types and styles of traps that are available to trap sparrows and starlings.  Here are only a few of them.  Depending on the type of housing you have, one of them should work.  Some work for starlings, others for sparrows.  Before you order one, verify that it will fit your housing and catch the bird you are trying to catch.

If they are bothering a wooden house where the front is removable for access, there's a simple little trap called the Insert Trap, that you attach inside the access hole and upon entering the house, the sparrow is trapped until you retrieve it.

If you have an aluminum house, they have a device called a Spare-O-Door. Again, the sparrow enters the house, is trapped and held in a plastic bag until you retrieve it.

And, if they are bothering your bluebird boxes, they have a Nest Box Trap that has the INT-1 installed in it to catch the ones that won't leave your bluebirds alone. All you have to do is temporarily replace your bluebird box with it until you catch the sparrow, then replace your bluebird house.

They can all be purchased at just about any major birding chain or you can contact the PMCA and see what they have for the type of housing you have.


There's a trap called a Deluxe Repeating Bait Trap. This trap works on their drive for food and if you follow the instructions that come with the trap, you can catch sparrow after sparrow. As its name implies, it is self repeating, working pretty much on the same principle as the S&S Controller. 20 and 30 sparrows a day are not unheard of with this trap.  The birds are kept alive and unharmed until you deal with them.  Yes, I bought two of them and yes, they work!  This is a good one to acquire and get them before they start nesting.

All of these traps mentioned catch the birds, and then hold them, unharmed, until you deal with them, and you already know where I stand on that issue.



Dealing with them once you catch them:


There are a number of different methods of disposing of these pests once you catch them in your trap.  I'll give a few here and the one you choose is up to you.


Aggressive Methods:


Many folks simply ring their necks, (myself included).  It's fast and instant and there is no mess.  Hold the bird in one hand and aggressively twist the head with the other.  The neck snaps and the bird is instantly dead.


Another method used by some, (myself included), simply grab the bird by the feet and with a quick aggressive snap of the wrist, swing the pest and 'snap' the back of its head into a very solid object such as a post or rock.  This is also instant and there is no suffering.


Non-Aggressive Methods:


This method is used by a number of folks that can't bring themselves to use the aggressive methods.  Place the pest bird (or birds) in a plastic bag and then spray a quick shot (2 seconds) of Ether (starting fluid) into the bag and then seal it.  The pests will expire within seconds and then they can simply be placed in the trash.  No further handling is required.


Another is pretty much the same, but is a little more labor intensive.  Again place the birds in a plastic bag.  Then, start the family vehicle up and stick the bag over the tailpipe of the vehicle.  After a few seconds, quickly remove the bag and seal it.  The fumes from the exhaust will kill the birds.  Again, no further handling required.



It may take a little effort on your part, but these pests can be controlled in and around your immediate area, and believe me, it's worth it.  After you witness the destruction these aggressive birds can do to a martin colony or bluebird trail, or any other cavity nesting species, I'm fairly sure you won't have any problem disposing of them.