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Guide to counting waders

Suggestions for how to count waders

Preliminary

The aim of this paper is to provide a guide in counting roosting waders.  It is not relevant to carrying out a count from the air or sea or to a count of waders in flight.

The following factors are relevant to a count:

  1. the size, nature and position of the roost site
  2. whether the birds are roosting in a single flock, a number of flocks or are spread out over the roost site
  3. if the site is subject to tidal influence, the height of the tide and its cycle (incoming or outgoing)
  4. the likely causes of disturbance while carrying out the count, including disturbance by the counter
  5. the distance between the counter and the birds
  6. the weather conditions
  7. the chosen equipment to record observations, for example, tally counter, notebook and pencil, tape recorder.

 The vantage point

After arriving on site, the first thing to do is to decide the vantage point from which to conduct the count.  Most of the factors are relevant to this but particularly factors 1 and 2.  The vantage points may even vary from day to day, depending on the height of the tide and the weather conditions. Because birds are more difficult to identify in partial or full silhouette, it is important to be positioned with the sun behind. In addition, for easier identification it is preferable to be positioned facing the birds as most waders roost with their heads tucked in their back facing into the prevailing wind. Of course this may not always be possible.

 When moving into position:

  • move slowly – fast, jerky movements will frighten the birds
  • be quiet – noise frightens birds
  • keep a low profile – keep below or close to the horizon and, if possible, use trees or other objects for cover
  • do not get too close – move progressively closer to improve the count accuracy
  • take note of the bird’s behaviour – this may give an idea of how long the birds are likely to stay in the area, eg, are they roosting quietly or are they about to be pushed off the site by a rising tide?

The count process

Step 1:

Think about jotting down the date, start time and other relevant information first.  This can so easily be forgotten.  Having moved into position, the first thing to do is to scan the birds to do a quick overall count of all the birds.  This may be useful if the count is disrupted for a variety of reasons, eg human disturbance or the arrival of a raptor. Counters should always be aware of what is happening around the roost site, particularly with a view to anticipating likely disturbances, for example by fishers.

 Step 2:

After getting an approximate total count, more time can be spent (preferably using a scope) getting a more accurate count.  At the same time, estimate the percentages of the more common species present while noting the less common species.

 Step 3:

Next, count the less common species.  The suggested method is to scan from one side of the flock to the other (preferably using a scope) counting individuals of each of the less common species.  When reaching the other side of the flock, work back in the opposite direction counting a new species.  Continue this process until all of the less common species have been counted.

 Step 4:

Having completed the count of the less common species, finish with an accurate count of the most common species (those for which an estimate has already been obtained under step 1).

 As soon as each species count is finished, it is important to record it in a notebook before moving on to count the next species.

 Depending on the size of the site and whether the birds are spread out over the site or in a number of flocks, further counts may be required from another chosen vantage point.

 As the count continues, be sure to add arrivals and out departures to the tally.  At the same time, note the numbers of birds leaving the site, the time of the departure and the direction they headed as this may indicate another roost site to which the birds have gone.

 Before leaving the site, check you have taken records of all species and that you have recorded the date, start and finish time, weather conditions and other relevant information for the count sheet.

 Other information

With practice, 2 species can be counted at the same time while scanning the birds.  Having this ability is especially useful if the number of at least one of the species is not particularly high.  For example, a Ruddy Turnstone or the orange legs of a Terek Sandpiper are species that can be counted easily with another species.  Some counters may find it easier to combine counts like this if a tally counter is used for one species and a mental count or tape recording made of the other species.

 Depending on the time of year and the roost site, some species can be confused.  Species falling into this category are Red Knot and Great Knot, and Greater Sand Plover and Lesser Sand Plover.  Counters may find it necessary to count the combined total of the 2 species and then go through the flock again to get a percentage of one of them of the total flock.  Although this may not yield an exact count, usually one of the species is dominant over the other so that it is relatively easy to arrive at a reasonably accurate percentage.

 At some roost sites, it is possible to count individual birds while at others it is not always possible.  When there are large numbers, especially in excess of 1 000, it may be necessary to count the birds in groups.  To do this, count a group of say 10, 50 or 100 birds individually to get an idea of what that number of birds looks like, different species will have differing densities.  Based on this assessment, count how many groups of that size make up the flock and multiply by the group size. The lower the group size, the more accurate the count is likely to be.

 Some counters find tape recorder particularly useful for counting large numbers.  This allows the counter to record species and numbers as well as other details while continuously observing the birds.  Recording observations can be made of individual species or birds in small groups.

 Counting waders requires good identification skills.  It takes practice.  Regular counters of a particular roost site soon get to know the site, the number of species and the number of birds likely to be seen at a particular time of year.  With this ‘home site’ advantage it is much easier to conduct a count and, at the same time, pick up on any significant changes in numbers.

 Remember, when carrying out a count it is important to cause as little disturbance as possible to the roosting waders.  Approach the birds quietly and slowly, they will soon become accustomed to your presence.  Some disturbance may be unavoidable but always bear in mind the paramount consideration is the welfare of the waders.  This is particularly important at migration times.