Fighting Florida's Iguana Invasion: One Man, One ZULUS HD

It all started with a crunch.

While walking through quiet Marco Island, John Johnson heard something unsettling. Following the sound, he found a large green iguana devouring an owl egg. As the frantic owl parents screeched, John knew exactly what he was looking at—an invasive species.

Green iguanas aren't native to Florida. Since arriving in the 1960s via the pet trade and accidental escapes, they've thrived. With lifespans of up to 20 years, females capable of laying as many as 71 eggs a year, and no natural predators, their population has exploded.

The result? Widespread damage. Reaching up to 5.6 feet in length and weighing over 15 pounds, iguanas dig deep burrows that undermine sidewalks and seawalls. Their climbing habits lead to roof damage and power outages. On top of that, they carry Salmonella, posing health risks to people and pets.

Over the years, Florida's iguana problem has grown from a mere concern to a full-fledged crisis. Seeing the destruction firsthand, John knew it was time to act. As a lifelong hunter who started out with a BB gun as a kid in the Pacific Northwest, John had the experience and passion to take on the iguanas.

In 2023, he founded Down Goes Iguana, a company dedicated to removing these invasive creatures from Marco Island's shores. That year, he removed 253 iguanas. By 2024, the number soared to 730, with 56% of them being females. This means John prevented over 20,450 iguanas from hatching, as each female can lay about 50 eggs annually.

As a registered Florida State Wildlife Control Officer, John carries out humane, regulated, and highly precise iguana removals. His mission is to protect Florida's native species and restore the balance of nature. And he's not alone in this fight.

When DNT first learned about John, it wasn't just his impressive numbers that stood out, but his precision, principle, and purpose. He embodies the values our gear was designed for. So, we decided to support his efforts by equipping him with the ZULUS HD 5x20 LRF scope, a versatile digital day-and-night vision device built for real-world performance.

For John, the ZULUS HD quickly became essential. Mounted on his Brocock Atomic Carbine air rifle, it gave him the clarity and confidence for precise shots, even in challenging conditions. As he puts it, "The lightweight ZULUS is a game-changer when I have to hand-hold."

Beyond portability, the ZULUS packs a range of features. John says, "It records video of everything you see in the scope and if you put on your best Marlin Perkins voice, you can record the exact moment live as it happens. It is great for some reticle screen grabs like you see here. This scope also features an in-scope rangefinder and infrared for night vision hunting."

By the end of June 2025, John had removed 620 iguanas in just six months—hundreds more than the same time the previous year.

Accuracy is critical for John, whose typical shooting range is between 15 and 50 yards. He explains, "Accuracy is also improtant for iguanas. Body shots rarely stop them, even head shots are often absorbed and they keep going. You pretty much must hit a dime spot in order to bring them down with a single shot." Iguanas are expert hiders. When perched in trees, finding them is only half the battle. Branches deflect pellets, and their tough, scaly skin makes them hard to kill. If the first shot misses, the iguana usually escapes into the brush, water, or worse—into a burrow to breed again.

Thanks to the ZULUS HD's exceptional clarity, John captures every detail, ensuring each shot is as accurate as possible. The built-in rangefinder offers real-time distance feedback, allowing for precise drop compensation. John also loves the video recording feature, which helps him review his shots to refine his technique, document his hunts, or ensure he complies with state guidelines.

Still, one of the biggest challenges remains locating iguanas in dense foliage. Recently, the DNT ThermNight caught John's attention. With advanced thermal imaging, it could help him spot iguanas more effectively in dense foliage or low-light conditions, whether in trees or on the ground. It could be the tool he needs to track these elusive creatures more efficiently.

John's mission is far from over—and neither is ours. As he strives to keep Florida's ecosystem in check, DNT is right there with the right gear.

Unlock your potential with the ZULUS HD and ThermNight series.