The methods explained

I-WeBS uses a well-established technique of counting the numbers of waterbirds at wetland sites by the ‘look-see’ method. All waterbirds are counted at each site once per month between September and March. Large sites involve a team of counters, and for most sites the teams are well established and always welcome additional support.


We ask for counts to be undertaken once per month between September and March. Often this is not possible and we urge a minimum of three counts, one in January and in at least two other months.

The equipment and experience required to take part in I-WeBS will depend very much on the site. Some sites are relatively small, and only support small numbers and few species. Quite often such sites can be easily covered with a pair of binoculars. A telescope is required for counting flocks at distance, and/ or sites that support large numbers and many species.

Large wetland sites are subdivided into smaller subsites. This facilitates counting of large wetland complexes within a three-hour period by allowing counters, or teams of counters, to identify and count section by section. It also gives us a better understanding about how birds use the site. This information is especially important to help inform on appropriate SPA boundary delineation, and on possible impacts of developments. It must be noted that most coastal sites are counted at, or near, high tides, and that waterbirds behave differently and may occur elsewhere in the site, or at other sites during other tidal states. Additional observations are required to determine waterbird distribution during other tidal phases. Further details about how to subdivide your site can be found here.

The time is takes to count each site should be less than three hours. This minimises the chance of duplicate counts of birds, particularly those that move around the site quite a lot.

Data should be compiled a the end of each visit and entered onto standard dataforms, or online. This process usually takes no more than 10 minutes per subsite and visit.


© 2019 BirdWatch Ireland   Terms Of Use   Privacy Statement