Garden birds counts

The selection of the nine most common city birds is based on the bird species which were found in the top ten in all garden birds counts in the period 2003–2006. 
Each year, the Netherlands Society for the Protection of Birds and SOVON collectively organise a national garden birds count in winter. During an hour, volunteers count the birds they spot in their gardens.
The Hatch Bird Monitoring Scheme set up by SOVON and Statistics Netherlands counts the birds in the hatching season and reveals the long-term trend.
The trend is the average trend of nine bird species common in urban areas during the hatching season (1990 = 100).
N.B. The figure does not reflect the results of the garden birds count.