Army helicopters flying over Queensland farm spark a sex frenzy among crocodiles

Army helicopters flying at low range, combined with violent electrical storms, cause a strange sex frenzy among crocodiles on a rural farm.

John Lever, owner of the Koorana Crocodile Farm near Rockhampton in Queensland, has noticed his crocodiles are particularly prolific since Singaporean Chinook helicopters started flying over his farm.

Experts are trying to understand why the helicopters, combined with recent thunderstorms, are having such a significant impact on the crocodile mating season.

But professors from the University of Queensland and Darwin University disagree on what exactly is driving the amorous activity.

Leading theories suggest that crocodiles take helicopter reflections as mating calls and changes in biometric pressure as explanations.

Recent thunderstorms and a warmer than average winter had also helped create perfect breeding conditions for crocodiles (pictured), farm owner John Lever said.

Dr. Cameron Baker, who specializes in the ecology, behavior and social structure of the estuarine crocodile at the University of Darwin, thinks male crocodiles mistake the distinct pops of the Chinook as mating calls of competing crocodiles.

‘It could produce a very low-frequency ‘thump, thump’ when it hits the water. That could coincidentally be similar to some of the sounds that large male crocodiles make when they say, “Hey, this is my turf,”‘ Dr. Baker told ABC.

The Singapore Armed Forces have been conducting bilateral military training operations at the Shoalwater Bay Training Area, about 100 kilometers north of Rockhampton, since 2020.

Officers flying the Chinook helicopters use the Koorana Crocodile Farm as a marker to change course mid-flight.

Mr Lever said every time they go over it triggers the same reaction, and he also believes it has something to do with their banging sound.

“We had a big Chinook that came down low because the guys wanted to take some pictures of the crocodiles. They were hanging outside the door… and of course Chinooks got a big thump, thump, thump, like that,” he told the publication.

After the Chinook left, Mr. Lever said his crocodiles quickly began mating.

The mating season for crocodiles runs from September to April in North Queensland, which coincides with the wet season, giving rise to another theory from Dr Barker.

‘They’re probably using (Chinooks) as a signal to say, “Hey, it’s getting wet”… and it’s a good time to start mating so that the eggs are ready to be laid at just the right time, ‘ says Dr. said Baker.

This year, Mr Lever said a particularly warm winter, combined with thunderstorms in early September, had created the perfect mating conditions.

Crocodiles usually fight with each other when they are ready to mate, Mr Lever said.

Lacking sophisticated voice boxes, the reptiles simply vibrate their windpipes to send messages through the water.

The added vibrations from electrical storms and low-flying helicopters help make the most of the mating season, which lasts only a matter of minutes.

Dr. Cameron Baker (pictured), a crocodile specialist at the University of Darwin, believes crocodiles could confuse the sounds of helicopters with mating calls from other crocodiles

Chinooks’ thumping sounds resemble the guttural sounds of crocodiles searching for a mate

Professor Craig Franklin, who specializes in zoology at the University of Queensland, said crocodiles mate during storms due to a change in barometric pressure.

“We don’t know what happens on farms, but our research shows that in the field they respond to rainfall… and of course they are often associated with a change in barometric pressure,” Professor Franklin said.

“These would all be signals that the crocodile relies on to time its reproductive activity.”

The Koorana Crocodile Farm produces approximately 2,000 eggs per year, of which 1,200 hatch.

Droughts and dry summers such as those seen in 2020 can drastically reduce these numbers, which has a major impact on farm profitability.

The farm experienced El Nino conditions for six years in the 1990s, but the Bureau of Meteorology’s announcement that El Nino would hit this year does not appear to have affected this season’s production forecasts.

Severe thunderstorms hit the Queensland coast in early September and the unpredictable weather conditions have continued since.

Chinook helicopters are also a staple this time of year since Australia signed a military training treaty with Singapore, which sees 14,000 of Singapore’s armed forces operating in the area.

The treaty allows Singaporean troops to participate in unilateral training in the region for up to 18 weeks per year for the next 25 years.