The black-capped petrel lives high in the mountains of Hispaniola and makes its nest in a deep burrow, among dense ravines or dry rocky ridges. It is an endangered seabird known as Diablotin (“little devil”) in Hispaniola because of its nocturnal habits and its eerie calls during the mating season.

From April 10 to 25, I partnered with Grupo Jaragua, the Dominican conservation NGO monitoring the bird’s nesting sites in the country, to track the movements of the petrel as they search for fish in the Caribbean Sea. For this, I used a combination of light-weight GPS loggers and solar powered base-stations. The loggers record the bird’s location every 30 minutes and transmit the data via UHF to the base-station whenever the bird comes back to its nest to feed its only chick. The logs are stored in the base-station’s 32Mb flash memory.

A Diablotin black-capped petrel ready to be tagged.

Given the remoteness of Diablotin’s nesting sites (30 miles from the coast, ~7,000ft above sea level, in the Sierra de Bahoruco National Park, Dominican Republic), I needed to rely on gear that was allowed on international flights, could easily be transported and adapted in the field (with limited electricity), withstand fog, rain and humidity, and was as cheap as possible. To power the base-stations, I was limited to Li-ion powerbanks (allowed on regular flights, easy to transport and affordable – unlike car batteries). Voltaic’s battery packs have been designed with low-power and IoT devices in mind. Their “Always On” feature, kept power to the system even when the Mataki logger was drawing very little to no current.

GPS tracking hardware:
– 3.5g Mataki-LITE (Debug Innovations)
– 150mAh Li-ion battery (TinyCiruits)

Base-station hardware:
– 1040 Micro Case (Pelican
– Mataki-CLASSIC (Debug Innovations)
– 916mHz antenna (Taoglas)
– 5V-3.7V step-down regulator (with micro USB input), with 1000µF capacitor
V44 USB battery pack (12,000mAh, 44Wh: Voltaic Systems)
5.5W solar panel, mounting bracket and cables (Voltaic Systems)
– Sugru and 2-part epoxy (waterproofing)

The base-station is protected in a pelican case, with the lid blacked out to keep the devices’ LEDs from appearing at night.  Since the battery’s 12,000mAh weren’t sufficient to keep the base-station running for the tracking period I needed (~ 1 month, at 480mAh per day), I paired it with one of Voltaic’s 5.5W solar-panels. The circuit is minimal: the solar-panel recharges the V44 battery, which delivers 5V-2A in “Always-ON” mode. The 5V-3.7V step-down regulator is connected to the base-station, in parallel with the 1,000µF capacitor.

solar powered gps logger

Base station on right before mounting. Lid is blacked out to prevent light from LEDs appearing.

I enclosed the base-stations in a 1040 Pelican case. The battery barely fit inside the case and I had to shorten the male 5.5×2.1mm input plug.  I covered the hole and the cables (for the antenna and solar-panel) with Sugru and waterproofed them with 2-part epoxy: this allowed me to adapt the base-station more easily to the local conditions. For good measure, I also added a handful of desiccant packs into the case. Finally, I deployed the base-stations in open canopy, as close to the nests of the Black-capped petrels we tagged as possible. I tried to position the solar-panel to face the midday sun, a time when the morning fog had already burnt off but the afternoon clouds not yet rolled in.

solar panel and gps logger

Deployed GPS Base Station with solar panel.

When we picked them up after a month and a half in the field and the base-stations had worked perfectly for the whole time. The battery levels stayed fairly consistent at 4.8V and with an individual
range of about 0.5V.

I’m glad I could rely on Voltaic’s gear for this study: thanks guys for your support and expertise!

And what about the Diablotin, you ask? Well, they flew between 1,200 and 2,800 miles in a week: a devil of a bird!

Bio: Yvan Satgé is a seabird biologist at the South Carolina Cooperative Fish Wildlife Research Unit, Clemson University. He is currently collaborating on studies of Brown pelicans in the southeast US and Gulf of Mexico, American flamingoes in Yucatan, Mexico, and Black-capped petrel in Hispaniola.

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