The Countryside Bird Survey (CBS) is an annual breeding bird survey coordinated by BirdWatch Ireland that has been ongoing since 1998. This survey aims to track the breeding population of Ireland’s most common and widespread bird species to discern annual trends.
Recently, an Irish Wildlife Manual was published by BirdWatch Ireland and National Parks and Wildlife Service, utilising eighteen years of CBS survey data titled “Countryside Bird Survey: Status and Trends of Common and Widespread Breeding Birds 1998-2016”.
This report outlines the breeding populations and the population trends throughout Ireland for 51 common bird species. Populations estimates are provided for all species which were recorded in 30 or more survey sites per year, on average. Population estimates are provided for 2011 to 2016, as well as 10-year and 18-year population trends. Breeding distribution trends are provided for each species, as a 10-year, 25-year and 44-year population trend.
The population trends over the 18-year period indicates that 47% of the common bird species in Ireland are increasing in population, while 27% of species have stable populations and 26% of species are in decline.
Breeding population estimates for a number of Birds of Conservation Concern in Ireland (BoCCI) red-listed species are outlined in the report, including grey wagtail, meadow pipit and yellowhammer. The population trend for grey wagtail indicates a 67.6% decline in population over the 18-year period (1998-2016), with a 42.2% decrease in distribution over the 25-year period, 1991-2016. Meadow pipit shows a 21.1% decline in population over the 18-year period and a 1.9% decrease in distribution over the 25-year period. Finally, yellowhammer shows a 4.4% increase in population over the 18-year period, but a 33.4% decrease in distribution over the 25-year period.
Other species of note included in this report, are sparrowhawk and kestrel. Populations estimates for these species are given as an indication of numbers and trends for this species rather than a robust population estimate due to their large home ranges and the difficulties in detecting these species using the CBS survey methodologies. The population estimate for sparrowhawk is 11,859 individuals, which represents a decline of 11.2% over the 18-year survey period, 1998-2016. However, there was a 42.6% increase in the distribution of sparrowhawk over the 25-years period, 1991-2016. The kestrel population was estimated at 13,500, a decrease of 44.9% over the 18-year period, 1998-2016 and a 22.1% decrease in distribution over the 25-year period 1991-2016.
The report also outlines the main pressures and threats facing Ireland’s breeding bird populations. These include habitat factors such as climate change, agriculture and forestry intensification, urbanisation and development. It also includes ecosystem factors such as pathogenic and pest plant and animal species, and a number of other factors.
The full report can be found here: https://www.npws.ie/sites/default/files/publications/pdf/IWM115.pdf