Phenology and Abundance of Migratory and Breeding Populations of Monarch Butterflies in the Pacific Northwest 2012–2024
Bibliographic record
Abstract
The decline of the monarch butterfly population in western North America has been documented by 28 years of community scientist counts from overwintering sites in California. However, no long-term studies on the status and dynamics of monarch populations during spring to fall are available. Using multiple datasets from online recording sites, social media, and personal observations, our study over 13 years shows increases and declines in warm-season populations in the Pacific Northwest (PNW) on a 2 to 4-year cycle that corresponds with fluctuations in overwintering populations. Overall, there was little evidence of a systemic decline in the abundance of monarchs in the PNW. Monarchs were reported in all PNW states and territories in all years, with the earliest annual first appearance in Oregon and the latest in British Columbia and a maximum seasonal range of 200 km north of the US/Canada border. Relatively equal numbers of unique sightings originated from each of three community scientist online recording platforms, with a larger number of unique sightings from personal observations/communications and multiple social media sites. The value of community scientist sightings for the rapid detection of substantial changes in populations was highlighted in August 2024 when weekly sighting data showed a substantial decline in PNW populations that may have been caused by poor survival of immature stages during a July heatwave. The conservation of monarchs in western North America will benefit from contemporary and high-value data on phenology and population dynamics, which we show can be provided by community science observations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".