monthly_pref_sight_sum_english

# Monthly prefecture-level bear sightings in Japan, 1997–2025 ## 1. Dataset overview This dataset contains monthly counts of bear sightings reported by Japanese prefectural governments for 30 prefectures on Honshu and Shikoku, Japan. For the prefectures included here, bears are Asiatic black bears (Ursus thibetanus). Brown bears (Ursus arctos) occur only in Hokkaido and are not included in this dataset. The data are aggregated at the level of prefecture × calendar year × calendar month. The time span covered is from 1997 to 2025 (up to May 2025; later months contain no rows in the CSV file). The dataset was compiled for a research manuscript on forecasting bear sightings in Japan that is currently in preparation. Once an associated article is published, users are encouraged to cite both the article and this dataset when reusing these data. ## 2. Files and structure This package contains the following files: 1. `monthly_pref_sight_sum_english.csv` - Main data file with monthly bear sightings by prefecture. 2. `README.md` (this file) - Documentation of variables, data sources, processing steps, and limitations. No additional code or scripts are included in this package. Data-processing code is available from the corresponding author on reasonable request (if not provided in the associated article or its supplementary materials). ## 3. Description of `monthly_pref_sight_sum_english.csv` ### 3.1 General structure - File format: comma-separated values (`.csv`), UTF-8 encoding - Number of rows: 3,277 - Number of columns: 4 - Each row corresponds to a single combination of (prefecture, year, month) for which a non-missing value was available in official statistics. ### 3.2 Variable definitions 1. `pref` (character) - Prefecture name in English. - Prefectures included (30): Aomori, Akita, Fukushima, Miyagi, Iwate, Niigata, Yamagata, Toyama, Ishikawa, Fukui, Nagano, Gifu, Shizuoka, Mie, Gunma, Tochigi, Saitama, Kanagawa, Tokyo, Shiga, Kyoto, Nara, Hyogo, Wakayama, Tottori, Shimane, Okayama, Hiroshima, Yamaguchi, Yamanashi. - Hokkaido and the eight prefectures in Kyushu–Okinawa are not included because either bears are absent or official occurrence counts are not published in a compatible format. 2. `year` (integer) - Calendar year (Gregorian). - Range: 1997–2025. 3. `month` (integer) - Calendar month of the sighting count. - Values 1–12 correspond to January–December. - For some prefectures and earlier years, official statistics are reported only for part of the year (often April–November). Months with no official value are omitted from the CSV file and should be treated as missing, not as zero. 4. `sight_sum` (integer) - Total number of bear sightings reported for the given prefecture, year, and month. - The exact definition of a “sighting” (e.g. number of incidents, number of reports, or number of animals) may differ among prefectures because each prefectural government compiles statistics using its own procedures (see Section 6: Limitations and important notes). - Units: count of reported bear occurrences (dimensionless). ### 3.3 Missing values and zeros - The CSV file contains no explicit missing-value codes (no NA, blank, or sentinel values). - If a particular (prefecture, year, month) combination does **not** appear as a row in the file, it should be interpreted as “no official value available” (missing), **not** as zero. - A value of `sight_sum = 0` indicates that the original source explicitly reported zero occurrences for that month. ## 4. Data sources The dataset was compiled from two types of official sources: 1. **Prefectural government publications** Monthly or annual statistics on bear occurrences were obtained from publicly available documents on prefectural government websites. For each prefecture, we primarily used tables and summaries contained in documents prepared for the Prefectural Wildlife Protection and Management Plans (tokutei chōjū hogokanri keikaku) and in dedicated prefectural reports that list annual and monthly numbers of bear occurrences. We did not use ad hoc press releases or agricultural damage statistics as data sources for this dataset. Because these sources consist of many separate reports across multiple prefectures and years, individual URLs are not listed here. All sources were open, publicly accessible documents at the time of data collection. 2. **Ministry of the Environment (national summary)** For recent years, we also used the national summary of bear occurrences compiled by the Ministry of the Environment, Government of Japan: - Ministry of the Environment, Government of Japan. “クマ類の出没情報について[速報値](直近5カ年)” Updated 5 December 2025. Available at: https://www.env.go.jp/nature/choju/effort/effort12/syutubotu.pdf This document provides preliminary (“速報値”) annual and monthly counts of bear occurrences for each prefecture, based on numbers reported by prefectural governments. ## 5. Data processing The following steps were used to construct `monthly_pref_sight_sum_english.csv` from the original sources: 1. For each prefecture, we identified official tables or summaries that reported bear occurrence counts by month and year in the documents described in Section 4.1. 2. Where prefectural or Ministry of the Environment sources directly provided monthly totals, we transcribed those values without further transformation. 3. Prefecture names were standardized to English spellings (see the list under `pref` in Section 3.2). 4. All counts were stored as integers in the `sight_sum` column. No rescaling or normalization was applied at this stage. ## 6. Limitations and important notes Users of this dataset should be aware of the following limitations: 1. **Heterogeneity among prefectures** The Ministry of the Environment notes that each prefecture compiles bear occurrence statistics using different procedures, such as counts of reports to the police or information provided by municipalities. As a result, the exact meaning of “one occurrence” is not perfectly standardized across prefectures. Counts should therefore be interpreted primarily as indices of relative temporal change within a prefecture, rather than strictly comparable absolute values among prefectures. 2. **Preliminary values** The Ministry of the Environment summary explicitly labels the data as preliminary (“速報値”) and states that values may be revised later. This dataset reflects the values available at the time of compilation and may not capture subsequent minor corrections. 3. **Spatial coverage** - Hokkaido is excluded because official counts of bear occurrences are not published in the same format. - The eight prefectures in Kyushu and Okinawa are excluded because bears are absent there. - Within the included prefectures, data coverage starts in different years (see the associated article, once available, or inspect the distribution of `year` by `pref`). 4. **Temporal coverage** - The earliest data included are from 1997. - For 2025, data are available only up to May at the time of data compilation. - Some prefectures report monthly data only for part of each year (e.g. April–November). Months outside the reporting period are omitted and should not be assumed to be zero. 5. **No individual-level information** The dataset contains only aggregated counts at the prefecture × month level. It does not include any spatially fine-grained locations, individual identifiers, or personally identifiable information. Users should consider these limitations when conducting comparative analyses across prefectures or interpreting absolute differences in counts. ## 7. Recommended citation When using this dataset, please cite: 1. The associated article that first describes this dataset (once published), for example: > Author(s). Year. Title. Journal name, volume:pages. DOI: article DOI. 2. This dataset: > Author(s). Year. Monthly prefecture-level bear sightings in Japan, 1997–2025. The exact citation details (authors, year, title, journal, and DOIs) should be updated once they are known. ## 8. Contact information For questions about data collection, processing, or interpretation, please contact the corresponding author of the associated article: - Name: Takeshi Honda - Affiliation: Yamanashi Prefecture Agricultural Research Center - Email: [e-mail]