Fig 1.
Number of surveys during which particular bird species were detected, independently of the detection method (recorder, observer or both).
Graph based on 148 surveys. The most widespread species, European skylark was detected during 132 surveys.
Fig 2.
Number of detected bird species by various detection methods.
Graphs show (a) all bird species, (b) songbird species, (c) farmland bird species and (d) meadow bird species by four detection methods: (1) recorder, (2) observer surveying birds within 50 m radius, (3) observer surveying birds within 100 m radius, and (4) observer surveying birds in unlimited radius. Boxplots show the median, interquartile range, and outliers.
Table 1.
Results of three generalised estimating equations.
Table 2.
Results of Wilcoxon two-related samples tests examining differences in detection rate of the most common bird species by recorders and observers surveying birds within 50 m (Obs. 50 m), 100 m (Obs. 100 m) and unlimited radius (Obs. unlimited).