You pull the SD card from a nest cam that's been deployed for eleven days, the previous card's data still unsynchronized on a laptop back at the office, and you realize you have no confirmed record of which SDCard_Nr was in which Camera_Nr at this nest. That gap — that single missing link — can invalidate your predation event attribution for the entire nest cycle. The 2024 CamTrap template is the system built to prevent that exact failure.
The Chain of Custody Problem in Nest Camera Deployment
Camera trap fieldwork for ground-nesting birds runs on physical media. SD cards are pulled, replaced, and returned to cards for re-deployment. When that cycle isn't tracked with the precision of a chain of evidence, the data becomes unreliable at the moment it matters most — when you're trying to attribute a predation event on a specific NestID to a specific PredatorID on a specific date.
The dual SDCard fields — SDCard_Nr_In and SDCard_Nr_Out — are not redundant. SDCard_Nr_Out records the card you removed; SDCard_Nr_In records what went back in. If those are the same card on the same visit, that's still worth recording explicitly. The card that gets lost in the field bag and accidentally deployed on a different nest six days later becomes traceable. Media chain-of-custody is not a bureaucratic nicety in this work; it's what makes your footage attributable to a specific nest at a specific location.
Camera_Nr links the physical hardware to the deployment record. When a camera fails — lens fogged, sensor knocked off-angle — you can pull all deployments for that unit and understand whether anomalous footage is a camera hardware issue or a genuine behavioral event. Without the equipment identifier, you're guessing.
What Actually Gets Recorded at the Nest
The Grid or Nest choice distinguishes survey type at point of entry. Grid-level checks and nest-level checks generate different data quality, different inference validity, and should never be merged into a single analysis pass without that flag. Researchers who combine them without stratification end up with inflated detection rates on nest-level outcomes.
NestID with 31U and UTM integer fields, and a separate Coordinates location field, builds a redundant spatial record. GPS coordinates are the ground truth. The UTM grid reference is the grid-based search protocol reference. They should agree. When they don't, it flags a data entry error before it propagates into the spatial layer.
Nr_Eggs and Eggstatus logged per visit gives you a developmental timeline without requiring full incubation stage modeling. The change in egg status between visits — combined with FinalNestStatus — gives you the nest fate classification directly. PredatorID closes the attribution loop: not just that a predation event occurred, but who did it, down to the species captured on footage.
After a Season of Nests
At the end of the monitoring season, the Researcher and Researcher2 integer fields let you stratify outcomes by observer. Experienced researchers find nests earlier, check them more frequently, and interpret ambiguous eggstatus differently. If one observer accounts for a disproportionate share of nests classified as abandoned rather than predated, you have an investigable quality signal — not just an unexplained variance term in your survival model.
Changed batteries is the operational field that the analysis never uses directly but that makes the operational workflow function. A dead camera at a nest with active eggs is an information gap. Knowing which visits included a battery change tells you which deployment windows were uninterrupted versus potentially compromised. The difference matters when you're reconstructing whether a predation event was actually captured or simply missed due to power failure.
The Nesthabitat choice field pairs with MeadowID to enable habitat-stratified survival analysis — comparing nest success rates across habitat types rather than treating the meadow as a uniform surface.