Field methods

I-WeBS uses the well-established technique of counting the numbers of waterbirds at wetland sites by the ‘look-see’ method (Bibby et al. 1992).  This involves counters recording the number of individuals of a number of waterbird species on frequent visits to pre-defined discrete wetland sites.  The species considered are those that are described.  Counts of gulls and terns are optional.  Though imperfect for certain groups of species, such as grassland-feeding waders, this method is the best available for general waterbird counting. 

All waterbirds are counted at each wetland visited.  Larger sites are subdivided into smaller count units to facilitate coverage by an individual or small group.  Large sites usually require a team of counters to ensure that counts are conducted over a relatively short period (within three hours), thus minimising duplicate counting of birds, particularly those that move extensively.  Separate data for each count unit covered are submitted on specially designed dataforms.