The British Trust for Ornithology (BTO) has been counting Grey Heron nests since 1928 and now it has made it easier for its army of volunteer surveyors by allowing them to record their observations on the internet.
The Heronries Census has covered 400,000 nests since it began. The survey collects annual counts of ‘apparently occupied nests’ in UK heronries and uses the data to monitor the population sizes of both Grey Herons and Little Egrets.
Counts are made at heronries by the BTO’s volunteers. It is one of the simplest surveys and requires no special skills.
So for 88 years, it has provided an annual estimate of the total UK breeding population of Grey Herons: this is the longest series of such data for any bird species in the world!
Until now, most counts have been mailed to BTO on special cards but, from 25 June, the option of direct online input of data became available to the observers for the first time.