ISS Protocols

The following guidelines are designed to assist you as an ISS cooperator, and to encourage basic consistency between surveys, for purposes of analysis and reference. We have tried to keep them to a minimum, in order that they don’t interfere with your shorebirding. If you feel they are too restrictive, or inappropriate to your area, or for some reason cannot be met, please contribute whatever information you can, and let us judge whether or not we can use it. Also remember that we are not just interested in high counts; low counts tell part of the story too, and are important factors when looking for changes in the use of an area.

We prefer that data be entered through the ISS eBird portal. For instructions on using eBird to enter your data, please see : How to Enter Data

We hope you can join us. If you have questions about the following materials, please don’t hesitate to contact Brad Winn (

Option 1) (Preferred) Our request is for one count to be made each third of the month throughout the survey period, at ten day intervals, on or about the following dates:

Spring Fall Winter (opt.)
15 Mar 15 Jul 5 Nov
25 Mar 25 Jul 15 Nov
5 Apr 5 Aug 25 Nov
15 Apr 15 Aug 5 Dec
25 Apr 25 Aug 15 Dec
5 May 5 Sep 25 Dec
15 May 15 Sep 5 Jan
25 May 25 Sep 15 Jan
5 Jun 5 Oct 25 Jan
15 Jun 15 Oct 5 Feb
25 Oct 15 Feb
25 Feb

(For those surveying in northern states, please begin your spring counts on April 1st if you can. For those in southern states, please begin your spring counts in mid-March, but you do not need to continue after June 5th.)

In general, the more counts made at an ISS site and the longer the record of years, the more valuable a census series becomes as a scientific record. A minimum of one count per month is much better than no survey at all, but we’d like to reiterate that the 10-day counts as described above provide the most useful record.

Try to survey on the recommended dates, or as close as possible +/-3 days, but don’t be discouraged if for some reason you can’t. Less frequent counts are also welcome and much better than none at all.  In recognition of this, we have outlined the following less preferred options:

Fall Migration Optional Survey Periods

Option 2) Survey your site once in July between the 11th and 31st, twice in August, twice in September and twice in October. Counts should be done at least one week apart. If you’d like to continue your counts after October 31st, we’d be delighted.

Option 3) Survey your site three times between July 15th and October 15th. The first count should be between July 15th and August 15th, the second between August 16th and September 15th and the third between September 16th and October 15th. Counts should be at least 14 days apart.

Spring Migration Optional Survey Periods

Option 2) Survey your site twice in April, twice in May and once in June between the 1st and 10th of the month. Counts should be at least 1 week apart. (For those in the Southeast, survey your site once in March between the 15th and 31st of the month, twice in April and twice in May.)

Option 3) Survey your site three times between April 1st and June 10th. The first count should be between April 1st and 23rd, the second between April 24th and May 16th and the third between May 17th and June 10th. (In the Southeast, the first count should be between March 15th and April 6th, the second between April 7th and 29th and the third between April 30th and May 22nd.) Counts should be at least 14 days apart.

Survey time of day and location

At coastal sites, please try to count during times when the census will be most accurate. At some coastal stations this will be at high tide when birds gather at resting areas, or at other sites it may be at lower tides when they are feeding. In any case, please record the tide as best you can in the “comments” field of your eBird checklist. At inland sites, please record whether you think the water levels were normal, high or low.

Survey accuracy

At best it is rather difficult to count a thousand small sandpipers milling about on a beach, and of course, we won’t ask you to try. However, we would like to know if your tally is actually a count, an estimate made by a more of less methodical procedure, or an outright (albeit educated) guess. A systematically-made estimate is one where you actually have a chance to count one or more portions of a flock and then extrapolate the total number form the count(s). An educated guess (“guesstimate”) is when you look at a flock and estimate the number of birds in it — it’s the method most of us use.  If you are using the ISS eBird portal, please write your method in the comments for any species you performed an estimate or guess for. 

Species identification

We cannot always identify all of the shorebirds we see. Often, for example, it is not practical to look at a large flock and identify each of 5,000 Semipalmated Sandpipers. Most of us check a portion of the flock, and make our identification, brushing over the possibility that one or two Western Sandpipers may be present. For the International Shorebird Survey, please record as “identified” ONLY the birds that you HAVE identified. Thus, if you identify 100 Semipalmated Sandpipers from among 5,000 peep, please record them as 100 Semipalmated Sandpipers and 4,900 peep. If you did not identify any of the sandpipers but presumed they were all Semis, please record them as 5,000 peep. If you are not sure whether a flock was comprised of Sanderlings or a mixture of Sanderlings and Sandpipers, please use “shorebird sp.” and make a note of what you think they were in the comment field. In short, resist the temptation to present accuracy that does not exist!