Thursday, 22 January 2015

Monitoring winter woodcock and snipe

Positions of woodcock encountered during nocturnal ringing activities and plotted using hand-held gps

Over the past few years counts of woodcock and snipe have been made whilst out in the fields trying to catch and ring these species, and sometimes their positions plotted as shown above. On some (most!) nights the birds are very jumpy and many of the birds seen are not possible to get close to, so it can be consoling to redefine the purpose of the visit to making counts rather than ringing the birds!. Nevertheless, over 800 woodcock have now been ringed within Pembrokeshire since Dec 2008 (this total includes Teifi RG's birds from the north of the county) and these have generated some interesting recoveries, with at least 10 from abroad, mostly Russia, and perhaps 30 or more local movements. It is hoped to summarise these at some point in near future.

It seemed this year that there were fewer woodcock and snipe being encountered than usual and so all the counts made over the last few winters were compared with those made so far this winter and then divided by the area of fields covered to give a density/Ha. After removing biases that appear as a result of a tendency to choose visiting the most productive fields, the figures are;


Data collected from 80 different fields with a total of 400 visits are used to produce the figures above and it appears that counting birds per field at night, if done systematically on a wide enough scale, is a simple way of monitoring change of wintering numbers in these species which both have declining breeding populations in Britain and Ireland, and are not covered well by existing schemes such as WeBS.

The variations in numbers are not necessarily due to population decline as they may simply reflect distribution changes that are weather related, and the mild autumn may mean many birds have not traveled this far west and other areas may have more birds than usual. A cold snap may change that.

Plenty of other research can be done off the back of these counts, especially if bird positions are plotted with gps which is also a simple and accurate way of recording counts. It seems that field size, slope and use, are all important factors affecting density of feeding birds.