It's Not a Deterrent, It's a Medieval Torture Chamber

My first and only exposure to "sticky mouse traps" was years ago, during my first week as a veterinarian. A distraught woman rushed into the clinic and presented me with a palm-sized square plastic tray with a little sparrow stuck to the adhesive, its feathered breast heaving in panic. The sticky trap had been placed in a garage, its intended target invading mice. The hapless bird had wandered onto the insanely sticky trap and been unable to wander off.

With the delicate precision of a surgeon, I painstakingly pried individual feathers and fluff from the glue. Unfortunately, but as intended by the trap's design, the more the bird struggled in its effort to escape not only the trap but also me, the more of its surface area became firmly attached to the glue. The desperate struggle (also part of the trap's design) was killing the fragile little bird by exhaustion as surely as the inescapable glue would eventually lead to deadly dehydration and starvation. It eventually became clear that the only good option for this little sparrow was a rapid and humane death by injection of euthanasia solution.

It was a sad end for the sparrow, but I could not help but think even then what a medieval torture chamber the sticky trap must be for the intended victim -- the rodent. To become hopelessly entangled in glue, uselessly struggling for escape, finally dying after hours or days from exhaustion and dehydration -- what a horrible death even for a rodent pest! 


And now I have learned from Aves Wildlife Alliance that my sparrow-sticky trap experience is not unique to me. In fact, sticky traps are marketed as a humane bird deterrent. Not death trap....deterrent. There are plenty of good reasons to want to deter birds and rodents from the home, but as with anti-coagulant poisons, it is becoming increasingly obvious that we must think beyond the intended target of our pest deterrents and traps to innocent bystanders such as pets and wildlife.

What follows is a blog by Rebekah Weiss of Aves Wildlife Alliance on the dangers of sticky traps for birds. We can't get away from pest deterrents, but we can choose humane deterrents.

For the Birds…or Maybe Not

Posted on April 2, 2013 by Rebekah

During the spring and summer seasons many of our bird friends are very busy building nests.  Sometimes our porches, light fixtures and outdoor decorations can be as appealing to bird families as the neighboring trees.  If you don’t mind using your back door for a couple of weeks you can enjoy watching the busy pair build their nest, lay eggs and raise their young.  If you would rather they not take up residence under your roof, there are a variety of ways to let the nest builders know your house is not open for birdy renters.

Please avoid Bird Repellent Gels, Pastes or Sticky Strips.  These products are marketed as non-toxic and safe for birds.  Here is an excerpt from one product, “A non-toxic, tacky bird repellent gel.  Can be used on ledges, sills, beams, rafters, signs, statues and hundreds of other outdoor surfaces to prevent pest birds from roosting. The gel does not harm birds – it simply makes surfaces uncomfortable, intimidating and uninviting.”  The reality is these products are not safe and do cause often deadly harm to the unsuspecting birds.  The sticky material coats the bird’s feet and any feathers it comes in contact with.  Small birds often struggle to the point of exhaustion to free themselves while larger birds may lose their ability to fly as a result of the glue on their feathers.  Despite what the label says, these products harm birds and are not safe!

This adult Eastern Screech Owl landed on a surface coated with one of these bird repellent gels.  He could not open his wings or his feet and would have likely starved had he not been found by a concerned home owner.  This little owl will be at the Aves hospital for several weeks while he molts out the sticky feathers and grows in new.

Bird Safe Alternatives:

Wedge a tennis ball or two in between the house and your outdoor light fixtures to keep your lights bird nest free.

Use ½ x ½ inch hardware cloth to close off any openings along the soffits, eves or under open porches of your house.

Use an angled piece of cardboard over ledges.

These items can be safely removed when the pair takes up residence elsewhere and does not cause any damage to your home or to the birds.

Of Mice and Mayhem: A Rodenticide Story

An urgent call comes in late one afternoon.

"My dog just ate rat poison! What do I do?"

In my experience as veterinarian and pet owner, rodenticide ingestion is a pretty common problem. My own dogs once discovered an unknown stash of warfarin pellets, ate it and then, before I could clean it up, ate the pile I made them vomit up. Geniuses. All of us.

Veterinarians field this type of call regularly. If the case involves a typical poison and is caught early, prognosis is very good with aggressive treatment. This time, however, the owner's next utterance stopped me cold.

"It's bromethalin."

Not a warfarin-type rodenticide, I thought to myself. Oh boy. And the packaging instructed not to induce vomiting, often our first line of defense in cases like this.

"I want you to hang up and call Animal Poison Control at 1-888-426-4435 and explain the situation," I instructed. "They will give you a case number for Rosco so we can handle this exactly right on our end. In the mean time, I will look into this particular rodenticide as well and call you back shortly."

Bruising on gums caused by
anti-coagulant rodenticide toxicity

As I feared, bromethalin is handled nothing like warfarin. Warfarin is an anti-coagulant that was developed for use as a rat poison by University of Wisconsin chemists in the 1940s. (It is now also widely used as an anti-clotting medication in people!) Warfarin interferes with the liver's ability to make clotting factors. Without vitamin K supplementation, affected animals bleed to death from internal and/or external bleeding. It may take one to five days before clotting problems start, but if a pet is caught in the act of eating a warfarin rodenticide, treatment begins immediately and most pets (like mine) recover uneventfully.

Mankind keeps trying to invent a better mousetrap, or in this case, rodenticide. There are multiple chemical offspring of warfarin which are more potent and require longer vitamin K supplementation, but bromethalin is in a class all its own. Invented when rats became resistant to warfarin, bromethalin causes swelling within the brain and spinal cord leading to depression, stumbling, paralysis, seizures, coma and death. Unlike warfarin's vitamin K, there is no specific antidote for bromethalin toxicity. Prognosis is pretty grim, especially if pets are already showing symptoms when diagnosed.

Dog hunts rodents in his backyard

Luckily it was determined that Rosco did not ingest enough of the bromethalin brick for it to cause toxicity. The owners were told to watch Rosco closely and bring him in to the clinic for supportive care if he showed any neurological symptoms.  I'm glad to report that Rosco has had no signs of toxicity since the incident! Unfortunately, the owners now face the daunting task of locating untold numbers of bromethalin bricks buried in their backyard. In their war against the rodents invading their basement, this family has unwittingly become trapped inside a veritable mine field of deadly rodenticide bricks.

Dead hawk resulting from rodenticide toxicity

Rodenticide toxicity is not just a problem for pets. Just as mercury "bioaccumulates" in marine food chains making it dangerous for people to eat too much of certain fish from certain waters, rodenticides affect large birds of prey such as red tail hawks. These predators eat affected rodents (easy pickin' because they're sick) and over time the toxins make the birds very sick. Rodenticide poisoning and death among unintended wildlife victims is a disastrous consequence of our efforts to control rodents using increasingly potent chemicals. Just as strychnine use in Wisconsin requires special permitting because of its potential to harm non-target animals, there are many who would like to see tighter controls on modern heavy-hitting rodenticides as well. If you must use a chemical means to control rodents, please follow the package directions carefully to limit the poison's impact on non-target creatures.