Winter Bird Surveys
What are winter bird surveys and why do we do them?
Here in the Scottish Lowlands, we carry out winter bird surveys at two of our farm sites (Balgonie and Balbirnie) to assess the abundance of different bird species. Some of these will be migratory and only visit Scotland in the autumn and winter months, such as fieldfare and redwings. Whereas others will be here all year round including commonly seen yellowhammers and chaffinches alongside many others.
Grey partridge (photo by Amy Mason)
Yellowhammer (photo by Amy Mason)
At Balgonie (the demonstration site), we carry out the winter bird survey at 15 transect points across the farm, 7 with measures and 8 without measures. This is reduced to 7 non-measure points at Balbirnie as it is a reference site. Measure points are close to habitat put in place to provide protection from predators, nesting sites and a food source for the birds such as hedges, and wild bird seed mix planted for the PARTRIDGE project. Non-measure points do not have this habitat nearby.
Example of a measure point with PARTRIDGE cover crop (photo by Rebecca Mills)
Example of a non-measure point (photo by Rebecca Mills)
For Scotland, each transect point is a circle with a 100m radius from which we record the number and species of birds that land within 10 minutes. The timer is started as we walk from the edge of the circle to the centre so we can count birds which may be disturbed by us as we approach the point. All the data is entered onto Sovon Avimap in the field and any factors which may influence the abundance of the birds is recorded, this often includes the peculiar sight of people flying model aeroplanes at Balgonie, which birds may mistake as potential predators.
The contrast of abundance of species at measure vs non-measure sites can be obvious sometimes, with the constant bustle in the hedges compared to the silence apparent at the non-measure sites. It can be difficult to identify some individuals as they flit from one area to another, so it is important be at the ready with our binoculars to spot their distinguishing features and listen to their distinctive calls.
I am really enjoying carrying out winter bird surveys as it has helped me improve my bird ID skills and tune into all the different bird calls. It can be hard to distinguish between the different calls, so it has been helpful learning funny mnemonics to remember them. Such as the memorable ‘A little bit of bread with no che-e-e-e-se’ for a yellowhammer call. It always feels like a great accomplishment when I can finally recognise a bird I did not know before and I hope to improve my knowledge to the point where I can carry out a survey on my own.
Written by Rebecca Mills, Scottish Lowlands Placement Student at the Game & Wildlife Conservation Trust. Edited by Fiona Torrance, Scottish PARTRIDGE demo site manager.