Attenborough Nature Reserve Grey Herons

In 2013, South Notts Ringing Group began monitoring the Grey Heron nests at Attenborough Nature Reserve (ANR) and colour-ringing the chicks.

This was seen as an extension to the project which North Notts Ringing Group had been running at Besthorpe Nature Reserve for many years.

Part of the study, and one of the reasons we are fitting colour rings, is to better understand at what age they breed and how far they disperse from their natal site to breed.

In some ways we thought the ANR nests would be physically easier to check than the Besthorpe nests because there were fewer nests in smaller trees. However, at ANR the nests were scattered around the many small islands so we needed to be in and out of the boat, with the ladder and kit, multiple times each visit.

Our initial thought was that the nests would be pretty permanent and used year after year so a large, numbered plaque was attached next to each nest. This would assist in identifying the nests between visits and help with nest recording.

Also, in theory, we could then monitor the nests from the footpaths surrounding the gravel pits. This worked on the odd occasion before the trees burst into leaf. We also discovered that the nests were not as permanent as we thought. We anticipated that some nests would be blown out over winter but discovered that most Heron nests moved from the West to the East of the reserve over the years, as shown in the maps below.



27 active Grey Heron nests in 2013

12 active Grey Heron nests in 2018

4 active Grey heron nests in 2023

The graph below highlights the decline in the number of active nests. Covid prevented any visits during 2020 and only one brief, early visit in 2021.

During the study period, along with the decline in nests, unsurprisingly the number of chicks ringed also declined, as shown below. Covid prevented any visits during 2020 and only one brief, early visit in 2021.



 

Population change

Our findings at ANR are consistent with the National trend determined by the British Trust for Ornithology » home » understanding-birds » birdfacts » Grey Heron, which says:

'The BTO Heronries Census, which has monitored Grey Herons since 1928, shows the species to have been more abundant in the early 2000s than at any time in the last 90 years. In the full survey of UK heronries, carried out in 2003 to mark the 75th anniversary of the Heronries Census, a record total of more than 10,441 Grey Heron nests were counted, around 75% of the estimated total population for that year. In the most recent full survey in 2018, a higher number of sites were visited than in 2003 but fewer nests were counted, reflecting a subsequent downturn”.

Mick P.