Online Ringing Report - Phenology

Phenology is the study of timing of events in an organism's life-cycle. Because ringers handle birds throughout the year they can collect information on the timing of various aspects of birds lives to help us better understand how they respond to environmental changes. In these graphs we show, for selected species, how many birds are breeding or moulting in different weeks of the year. We also show how this relates to the number of nest records submitted and to the timing of breeding over the past five years. A separate graph shows weights of each species change through the year

Useful Notes: The lines representing this year are 'smoothed' through the weekly data points (which are not shown) to minimise the effects of fluctuations caused simply by chance. Not all ringers record the presence of breeding or moult state in all birds (for a variety of reasons) - this will have the effect of lowering the peak frequency in the graphs to less than 100%.

Chaffinch by Allan Drewitt

What do you want to look at?

Phenology by Species

Choose a species and a year then click 'Go!'

You are very welcome to use the information in these reports in any publications, talks, etc.  Please use the following acknowledgement:

The BTO Ringing Scheme is funded by a partnership of the British Trust for Ornithology, the Joint Nature Conservation Committee (on behalf of: Natural England, Natural Resources Wales and Scottish Natural Heritage and the Department of  Agriculture, Environment and Rural Affairs (Northern Ireland)), The National Parks and Wildlife Service (Ireland) and the ringers themselves.

The citation is:

Robinson, R.A., Leech, D.I. & Clark, J.A.(2018) The Online Demography Report: Bird ringing and nest recording in Britain & Ireland in 2017. BTO, Thetford (, created on 7-September-2018)  

We hope you will find these summaries useful and would appreciate any comments for further improvements and enhancements. These should be emailed to ringing [at] bto [dot] org.