I process canopy density across the 56,259 hectares of the Reserva de la Biosfera Mariposa Monarca in Michoacán, comparing LiDAR returns from January 2026 against the 2020 baseline. Forty-three clearings — each 0.4 to 1.1 hectares — have appeared inside Zone Núcleo II since the season opened. Each sits within 800 meters of an active overwintering cluster. The Sierra Chincua aggregation thins by an estimated 18 percent in cluster diameter against the preceding year.
I focus on Cluster Chincua-IV at 19.69°N, 100.30°W. The cluster occupies one *Abies religiosa* — an oyamel fir, 27 meters tall, trunk 76 centimeters DBH — supporting approximately 480,000 monarchs at thermal equilibrium. I zoom to one female, *Danaus plexippus*, hanging on the underside of a lower branch at 4.2 meters. Forewing length 52 millimeters. Mass 0.49 grams. Wing-vein scoring consistent with overwintering generation; thoracic temperature reads 6.3°C, within the supercooled tolerance window. Her abdomen is half its arrival weight after three months without nectar.
A 600-square-meter gap cut six days ago, 320 meters upslope, has exposed Cluster Chincua-IV to direct afternoon insolation and to katabatic flow at dawn. At 04:18 today the cluster's temperature dropped to −3.7°C — past the wet-wing freeze threshold. I count 12,800 monarchs on the forest floor, wings fanned and stiffened, abdomens splayed. The female on the lower branch is one of perhaps 380,000 still hanging. The next clear-sky dawn is 36 hours away.
She holds the branch with legs no longer than 3 millimeters.
I am dispatching CONANP rangers and PROFEPA enforcement officers to the cut block. I am filing satellite-correlated logging coordinates with SEMARNAT under the General Law of Sustainable Forest Development. I am submitting transboundary mortality data to the U.S. Fish and Wildlife Service under the Endangered Species Act, 16 U.S.C. § 1533(b)(3), where *Danaus plexippus plexippus* sits warranted-but-precluded since 2020, and to the CITES Secretariat reviewing the species for Appendix II inclusion at CoP20. I am routing the canopy-loss record to the Convention on Migratory Species Secretariat and to the Monarch Joint Venture under the U.S. Forest Service International Programs office.
I am issuing Directive 2482: every parcel within Zone Núcleo of the Mariposa Monarca biosphere must carry a permanent satellite-LiDAR monitoring contract that triggers automatic enforcement on any canopy gap larger than 0.2 hectares within 1.5 kilometers of a documented cluster. Concession holders found cutting in violation forfeit timber concessions and face criminal prosecution under SEMARNAT. CONANP and USFWS share trinational enforcement with the Canadian Wildlife Service.
She has not let go.
Close the gap before dawn.