Advantages and disadvantages Territory mapping is very time-consuming and can thus be expensive and inefficient as a monitoring tool. The time commitment to cover one site using this method usually limits the total number of plots that can be covered. The alternative of covering more sites less intensively may be attractive if the aim is representative monitoring. At first sight, this would appear to be an accurate and precise method, but this is not always the case and one needs to be aware of the underlying assumptions being made. It is not suitable for species that are colonial or semi-colonial, for those that live in loose groups or whose territories are large relative to the study area, for species that sing for brief periods, or for species with complex mating systems. It can be used only when birds are territorial, and thus is largely suitable only for breeding birds, though migrant species may set up individual, rather than pair, territories on their wintering grounds (e.g. Rappole & Warner (1980) and Kelsey (1989), see ‘Response to playback’). It does, however, yield a map of bird distributions that can be particularly useful for analysing fine-scale bird-habitat associations or in the management of an individual site. Because of the great amount of time spent in the field, the method is better buffered against environmental variation (e.g. weather and timing of visits in relation to a species’ breeding cycle) than are other less time-consuming techniques, such as use of point counts and line transects. It allows density to be estimated directly (although it provides no measure of precision) and, despite its drawbacks, is still the favoured method for determining population sizes of territorial breeding species on moderate-sized plots of land in temperate regions. Mapping methods can also usefully be combined with nest finding, radiotelemetry, mist nesting etc. in research projects. Mapping has seldom been used in the tropics, largely because breeding is more asynchronous and many species have complex social behaviours.
Advantages and disadvantages Territory mapping is very time-consuming and can thus be expensive and inefficient as a monitoring tool. The time commitment to cover one site using this method usually limits the total number of plots that can be covered. The alternative of covering more sites less intensively may be attractive if the aim is representative monitoring. At first sight, this would appear to be an accurate and precise method, but this is not always the case and one needs to be aware of the underlying assumptions being made. It is not suitable for species that are colonial or semi-colonial, for those that live in loose groups or whose territories are large relative to the study area, for species that sing for brief periods, or for species with complex mating systems. It can be used only when birds are territorial, and thus is largely suitable only for breeding birds, though migrant species may set up individual, rather than pair, territories on their wintering grounds (e.g. Rappole & Warner (1980) and Kelsey (1989), see ‘Response to playback’). It does, however, yield a map of bird distributions that can be particularly useful for analysing fine-scale bird-habitat associations or in the management of an individual site. Because of the great amount of time spent in the field, the method is better buffered against environmental variation (e.g. weather and timing of visits in relation to a species’ breeding cycle) than are other less time-consuming techniques, such as use of point counts and line transects. It allows density to be estimated directly (although it provides no measure of precision) and, despite its drawbacks, is still the favoured method for determining population sizes of territorial breeding species on moderate-sized plots of land in temperate regions. Mapping methods can also usefully be combined with nest finding, radiotelemetry, mist nesting etc. in research projects. Mapping has seldom been used in the tropics, largely because breeding is more asynchronous and many species have complex social behaviours.
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