Bird ringing report 2019

Derek Gruar introduces the 2019 report from the bird ringing and monitoring that takes place at Paxton Pits

The British Trust for Ornithology (BTO) has used Constant Effort Site (CES) bird ringing to monitor the abundance, breeding success and survival of 24 common breeding songbirds since 1986. Paxton Pits Nature Reserve is one of over 140 sites across the UK that contributes data to this programme.

Monitoring is carried out by qualified volunteer bird ringers during the breeding season, with twelve visits between May and early September where the same nets are set for same standard length of time for each visit. At Paxton, we monitor the site with eight mist-nets totalling 140 metres in length that are set between 5.30-11.30am. 

The results are used to measure changing population sizes (comparing the number of adult birds caught each year) whilst the ratio of juvenile to adult captures provides a measure of breeding success. In addition to ringing new birds we also record data for all birds we recapture; those of adult birds ringed in previous years are used to estimate annual survival rates. 

Some birds ringed in 2019. L-R House Sparrow, Bullfinch, Reed Warbler.


In 2019, we conducted 15 bird ringing sessions at “The Sanctuary” at Paxton Pits Nature Reserve. The first session was in early January and our standard CES monitoring began in May and continued until late August. 2019 proved to be another improvement on the previous two CES seasons. Post CES we managed to successfully target late summer migrants on three visits in September. The final session of the year was a demonstration event where visitors from the Friends of Paxton group were invited join us during the ringing session. Sadly, the poor weather in autumn prevented any further visits.

Over the year, mild winter conditions were replaced with cold and wet weather in late spring. We were fortunate that conditions had improved by the time the start of the 2019 CES ringing season was due. Fine and dry weather in May enabled resident species to raise broods with Blue Tits, Long-tailed Tits and Robins making up the most of the early season catches. June however was quite wet which seemed to affect breeding warbler numbers, especially Blackcaps which were surprisingly absent. The record warmth of July seemed to suit Phylloscopus warblers with a record combined catch of Willow Warbler and Chiffchaff on 21st July. Late summer saw an increase in thunderstorms and in August numbers of birds ringed were steady rather than spectacular. The highlight was the number of fledged Bullfinches. 

Overall, we succeeded in conducting ringing sessions on eleven of the twelve allocated time periods. A total of 346 new birds were ringed of 23 different species. This was a further improvement on 2018 as bird populations at Paxton seem to be recovering after the poor year in 2017. An average of 34 new birds ringed per visit is just above the 10 year mean.

New report on the birds and wildlife of Paxton Pits

Earlier this year, The Friends of Paxton Pits Nature Reserve produced the first annual comprehensive report on the numbers of birds and wildlife of Paxton Pits for ten years. Collating information gathered by a huge range of volunteers who conduct regular surveys, the report lists all the species sighted on and around the reserve in 2017, from scarce occasional visitors such as ring ouzels and ospreys, all the way through spiders and dragonflies to butterflies, fungi and, for the first time, mammals.

The report makes sobering reading in many ways, with dramatic reductions in such iconic species as swallows, house martins, spotted flycatchers and nightingales, as well as brown hares, hedgehogs and water voles. However, there is some counterbalance, with big increases in little egrets, red kites, various species of gulls and common buzzards, which is now the UK’s most common breeding raptor. There are also more badgers, muntjac deer and otters than there were ten years ago.

The reports will once again be an annual occurrence, helping everyone who is interested to keep tabs on their favourite species. It also goes to show how important your sightings are to us – please do report what you see in our book at the Visitors’ Centre when you visit, or by emailing

The report has been put together with help from a huge number of people including Grainne Farrington, Adrian Hyde, Roger Lloyd, Mike Thomas, Jim Stevenson and Neal Parking – among many others. The Friends are extremely grateful for everyone’s help.

Copies are available for anyone to buy from the Visitors’ Centre for just £5 each.