Table 1. Description of environmental covariates at range and point-level used to examine possible predictors of variation in daily range size and movement rates of birds in various forest stands.
| Variable | Description | Value mean/median and range |
|---|---|---|
| Point-level | ||
| BP | Number of beech trees (diameter at breast height DBH >15 cm) around tracking location |
3.1 (0–29) |
| SP | Number of spruce trees (DBH >15 cm) around tracking location | 11.7 (0–42) |
| XP | Number of all trees (DBH >15 cm) around tracking location | 16.4 (0–42) |
| HP | Shannon–Wiener index of tree species diversity (DBH >15 cm) around tracking location (based on H′ = −∑pslog(ps), where ps is the proportional abundance of species s) |
0.4 (0–1.8) |
| TP | Local temperature at tracking location during time of observation | 9.5 (−1.7–21.5) °C |
| DtP | Time difference of observation to sunrise time of the same day | 169.8 (−30–496) min |
| S.typeS | Type of forest stand surrounding tracking location based on dominant tree species as classified by regional forest management map |
5 different levels (Beech, Beech-mixed, Spruce, Spruce-mixed, Non-spruce conifer) |
| S.ageS | Age of forest stand surrounding tracking location as classified by regional forest management map |
69.4 (0–140) |
| Range-level | ||
| JulDayR | Day of observation counted onwards from 1st March, comprising a continuous seasonal measure; foliage density and arthropod species presence can be expected to change because of the strong seasonal variation in the study region |
54 (9–111) |
| TempR | Mean temperature [C] during the time of daily tracking (averaged from point-level measures) |
8.3 (0.8–17.9) |
| StandNoR | Number of distinct forest stands, with distinct forest management practice and tree types; derived from regional management map |
2 (1–8) |
| BeechStandR | Proportion of area underlying the daily range estimate covered with forest stands dominated by beech; derived from regional management map |
16 (0–100) |
| SpruceStandR | Proportion of area underlying the daily range estimate covered with forest stands dominated by spruce; derived from regional management map |
47 (0–100) |
| BeechTreeR | Average number of beech trees at point locations within daily range; averaged from 30 locations used for daily range estimate |
1.3 (0–17.0) |
| SpruceTreeR | Average number of spruce trees at point locations within daily range; averaged from 30 locations used for daily range estimate |
11.7 (0–28.8) |
| TotalTreeR | Total average number of trees at point locations within daily range; averaged from 30 locations used for daily range estimate |
18.2 (1.0–30.4) |