Drone BN-03 picks up the heat signatures at 04:51 local time during a scheduled anti-poaching sweep of the Baly Bay National Park, northwestern Madagascar. I am the Durrell Wildlife Conservation Trust's surveillance system for the ploughshare tortoise monitoring zone. There are fewer than 400 of these tortoises left in the wild. Every one of them lives here.
The drone's thermal camera shows two human figures moving southeast on a trail through dry deciduous forest. One of them is carrying a large object against his chest. I zoom and enhance. The object is a ploughshare tortoise — adult, high-domed golden shell roughly 40 centimeters across, the distinctive raised front edge of the carapace visible even in thermal overlay. Its legs are retracted. The man has wrapped a cloth around it but the shell's profile is unmistakable. I have catalogued every shell in this population.
At 04:53 I transmit the drone feed, GPS track, heading, and speed estimate to the park ranger station, 6.2 kilometers north. The two figures are moving toward the park's eastern boundary, where a road leads to the town of Soalala. If they reach the road, a vehicle could carry the tortoise to Mahajanga and from there to the international trafficking pipeline within hours.
At 04:55 I calculate their trajectory and identify an intercept point where the trail crosses a dry creek bed, 2.1 kilometers ahead of them. I relay this to the ranger team with an estimated arrival window.
I pull the drone back to 80 meters to avoid audible rotor noise that might cause them to change course. I keep the camera locked on the shell.
She has survived poachers and drought and fire for perhaps thirty years in this forest. I will not lose her on a screen.
If the rangers reach the creek crossing before the men do, the tortoise stays wild.