Have you seen a flock of terns roosting along the coast?


I-WeBS has been designed to gather information on the distribution and abundance of Ireland's wintering waterbirds and their important sites. To date, more than 80 sites have been identified as of significant importance for wintering waterbirds and have been designated as Special Protection Areas (SPAs) under the European Union Birds Directive.

Some sites that are important for wintering waterbirds hold important concentrations of birds at other times of year too – most notably birds on passage during migration between their breeding and wintering grounds. This season the I-WeBS Office will focus on gathering information on post-breeding aggregations of terns at key wintering sites around the Irish coast.

Nearly 50 sites have been identified as post-breeding tern roosts to date around the Irish coast. Every record is valuable, whether its from a previously-known site or a new one, or whether you counted every bird or can only estimate numbers present.
See below for a recommended survey methodology, but counts that deviate from this are still very welcome! 

Recommended Survey Methods

1.   Please undertake a number of visits (ideally, at least two) between mid-August and early September, when numbers of congregating terns are at their peaks.

2.   Ideally at least two counts would be undertaken at dusk on a rising/high tide. This is when the terns are pushed into a small area of the beach and are probably closer to you and easier to count. An additional low tide count would also be valuable, to capture the areas used at a site at different tidal states. Please ensure to record the tidal state during your count.

3.   Record total tern numbers and where possible to distinguish, please estimate the totals of each species present.

4.   Wherever possible, please record the proportion/number of juvenile terns and/or ringed individuals - this provides valuable information on the origins of flocks and the rate of turnover at the site.

5.   If faced with a big flock, try to estimate the proportions of the different species present within a sample of the flock and use the ratio to estimate totals of each species

6.   Provide any additional details about the flock that you may consider useful/interesting.  If the birds are disturbed please record the cause of disturbance.

7.   Please ensure to mark the precise location of any flocks you see on each count on the map (link provided below).

To begin, please enter the details of your visit on the next page. Thank you for your help and support with this work.