Advantages and disadvantages
The great appeal of listing methods is their simplicity. Counts of individuals are not needed, allowing more time to be spent on identification, which is particularly valuable for inexperienced observers, in poorly known regions, and in bird-rich habitats. They provide a simple measure of relative abundance, allowing indices to be compared between species and sites. However, the index produced will be most useful for moderately abundant species. Very common species will be recorded on all lists – and thus true variation in abundance of these species will be masked and trends dampened. Very rare species will be recorded on no, or few, lists, giving little variation in abundance between species and sites, often no better than recording their presence or absence. An advantage of the McKinnon lists over time-limited lists is that, because observers are not restricted to particular time periods, less skilled observers – who take longer to find and identify species – can still produce lists that will be comparable with those of more experienced observers. The more skilled observers will simply collect more lists. Data from such lists can be used to produce maps of distribution and geographical patterns of relative abundance. However, this approach has the considerable weakness that the index of abundance it produces is relative to that of other species
(see Chapter 3).
Advantages and disadvantagesThe great appeal of listing methods is their simplicity. Counts of individuals are not needed, allowing more time to be spent on identification, which is particularly valuable for inexperienced observers, in poorly known regions, and in bird-rich habitats. They provide a simple measure of relative abundance, allowing indices to be compared between species and sites. However, the index produced will be most useful for moderately abundant species. Very common species will be recorded on all lists – and thus true variation in abundance of these species will be masked and trends dampened. Very rare species will be recorded on no, or few, lists, giving little variation in abundance between species and sites, often no better than recording their presence or absence. An advantage of the McKinnon lists over time-limited lists is that, because observers are not restricted to particular time periods, less skilled observers – who take longer to find and identify species – can still produce lists that will be comparable with those of more experienced observers. The more skilled observers will simply collect more lists. Data from such lists can be used to produce maps of distribution and geographical patterns of relative abundance. However, this approach has the considerable weakness that the index of abundance it produces is relative to that of other species(see Chapter 3).
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