The Swiss Common Breeding Bird Monitoring (“Monitoring Häufige Brutvögel” MHB) is a long‐term study organized by the Swiss Ornithological Institute. Its main goal is to collect data for estimating breeding population trends of relatively abundant and widespread species. Since 1999, 267 one‐km squares laid out in a mostly systematic grid across all of Switzerland have been surveyed annually by skilled, mostly volunteer ornithol...

Species’ assessments must frequently be derived from opportunistic observations made by volunteers (i.e., citizen scientists). Interpretation of the resulting data to estimate population trends is plagued with problems, including teasing apart genuine population trends from variations in observation effort. We devised a way to correct for annual variation in effort when estimating trends in occupancy (species distribution) fro...

The World Conservation Union (IUCN) published guidelines to apply the criteria developed for global red lists at subglobal levels. So far only a few national red lists have been prepared according to these regional guidelines. We present a procedure based on the regional guidelines that was developed for the most recent red list of breeding birds in Switzerland. Special attention was given to step 2 of the IUCN regional guidel...

We propose a quantitative zonation of Switzerland based on the distribution of breeding birds. We use a combined dataset from two nationwide bird censuses 20 years apart to account for distribution changes between the censuses. This approach approximates the ‘potential’ distribution of species more closely than a dataset from one period only. A numerical approach with correspondence analysis and non‐hierarchical clustering res...