Invisible but Identifiable: p-Chips as a Reliable Marking Method for Amazonian Bats

Juan Jesus Pellón, Naija Cuzmar, Jorge Luis Mendoza, Cristian Tirapelle, Nick Fluker, Gideon Erkenswick, Mrinalini Watsa

Marking techniques are essential for studying bat ecology and informing conservation efforts, yet many existing methods present challenges related to size, tag detectability, and long-term retention. P-Chips, ultra-miniaturized transponders detectable via red laser light, offer a promising alternative to traditional banding or passive integrated transponer (PIT) tags. While their use has been successfully demonstrated in captive bats, their effectiveness in free-ranging populations remains largely untested. To evaluate the field applicability of p-Chips, we conducted a two-year field study in the Peruvian Amazon, tagging 121 individuals across 21 species. We documented 23 recaptures, with all p-Chips remaining functional over both short term (< 1 month) and long term (~ 1 year) periods. Notably, no adverse effects such as scarring or tissue damage were observed. Red LED illumination facilitated rapid tag detection, reducing handling time. Recaptured bats revealed high site fidelity in most individuals, although some traveled over 1 km. These findings support the use of p-Chips as a viable, detectable, minimally invasive, and cost-effective alternative to PIT tags, particularly for small-bodied species. We recommend further research to optimize P-Chip technology for broader application in wildlife tracking and conservation.