Online Resource 5 – Species occurrence change categories and ecological classifications (Table S4)
Description

This resource contains the species-level dataset used to classify temporal changes in bird occurrence frequencies between the two survey periods (T1: 1999–2005; T2: 2023–2024).
For each species, the table includes occurrence frequencies in both periods, the change in occurrence, habitat and trophic classifications, and quartile-based occurrence categories.

Contents
Table S4 — Species occurrence change dataset
Variable descriptions
Species — Scientific name following current taxonomic nomenclature
T1_occurrence — Number of sampling units in which the species was recorded during T1 (1999–2005)
T2_occurrence — Number of sampling units in which the species was recorded during T2 (2023–2024)
Delta_occurrence — Difference in occurrence frequency between T2 and T1:
Δ = T2_occurrence − T1_occurrence
Positive values indicate increases; negative values indicate decreases.
Habitat_group — Main habitat association (forest, farmland, shrubland, generalist, others)
“Others” includes species associated with aquatic, rocky, urban, or less represented habitats.
Trophic_niche — Broad trophic guild (invertivore, granivore, omnivore, scavenger, vertivore, aquatic predator, terrestrial herbivore, aquatic herbivore)
Quartile — Occurrence class based on T1 frequency distribution:
Q1 (rare), Q2 (uncommon), Q3 (common), Q4 (widespread)
Quartiles were defined using T1 values to assess whether temporal changes differ according to initial species frequency.
Trait data sources

Pigot AL et al. (2020) Nat Ecol Evol 4:230–239
Storchová L, Hořák D (2018) Glob Ecol Biogeogr 27:400–406
Wilman H et al. (2014) Ecology 95:2027

License

CC BY 4.0

Version

1.0 (2025-11-30)