The following trend codes are used in the online application:
In cases where the trend is less certain a "?" may be appended, or 2 trend types separated by a "/"
e.g. DEC/STA. However this has been avoided as much as possible.
Start & End Year
All population trends require a start and end year that determines the period for which the trend
applies. For the CSR reports, the trend period is shortened to a maximum of 10 years. In some arid and semi-arid regions (e.g. parts of Australia), where waterbird numbers are affected by cycles of draught and flood, longer periods were used to remove the impacts of short- or medium term fluctuations.
From CSR5 and WPE5 onwards, four categories of trend qualities were used following the method developed by the International Wader Study Group:
1. No idea: No monitoring at international scale in either breeding or non-breeding/wintering periods. Trends unknown. This category also includes populations where trends are statistically uncertain unless other evidence allows estimation of the trend.
2. Poor: Some international monitoring in either breeding or wintering periods although inadequate in quality or scope. Trends assumed through partial information.
3. Reasonable: International monitoring in either breeding or non-breeding/wintering periods that is adequate in quality or scope to track direction of population changes.
4. Good: International monitoring in either breeding or non-breeding/wintering periods that is adequate in quality or scope to track direction of population changes with defined statistical precision.
References for population trends
In cases where numerous sources have been used to calculate the trend, all sources are given, and explanation is provided in the Notes.
More information concerning the trend estimate are provided here as necessary.