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Chesil Little Tern Recovery Project Report 2020

Chesil Little Tern Recovery Project Report 2020
Posted : January 8, 2021

Overall, a very positive season for the Little Tern Recovery project, despite Covid restrictions and the absence of a seasonal project officer. The volunteer team worked incredibly hard and deserve huge credit for the colony producing 30-plus little tern chicks.  Report Summary is detailed below:

2020 was a challenging year for the project because of Coronavirus restrictions. The seasonal project officer post was withdrawn in March and the RSPB project manager was put on furlough until 18 May. Despite concern from local volunteers, it looked as though there would be no intervention at the colony during the season.

The RSPB set up an Exceptions Panel to see what might be done for a few priority breeding species and agreed to limited intervention in April at the colony, with staff and volunteers operating under a strict Covid protocol. In mid-May, volunteers with RSPB wardening staff erected the anti-predator fence and the project manager was brought back to coordinate a limited wardening rota. A pre-season decision to pilot a daytime-only wardening scheme provided a further management challenge.

Reduced capacity had several knock-on effects, most notably in delaying the transfer of some nests onto sand patches and reducing the number of nests that were translocated into the fenced area. This increased both the number of eggs that were lost to chilling on pebbles and predation risk to nests outside the fenced area. There was also a significant loss of first clutches to predation by a male hedgehog: 93 first clutch eggs were predated (73% of the total) in early June, and this subsequently reduced overall productivity.

Despite this, there were some notable successes in 2020:

  • An increase in the breeding population to a minimum of 50 pairs, double the number present in 2013. This is undoubtedly the result of good productivity between 2013-18, with many young terns now returning as mature adults. Approximately 20% of pairs nested outside the anti-predator fence, mainly around the Black Hut and the foreshore.
  • An estimated 30-plus chicks fledged, giving a productivity of c. 0.6 chicks per breeding pair, just below the 0.7 chicks per pair that is probably needed to maintain colony size. The colony may well have produced more than 30 fledglings, and it is possible that the 0.7 figure was achieved, although it is unlikely to have been much higher.
  • The impacts of egg loss were offset to a large extent by success in reducing kestrel predation. The new kestrel nest site on Portland west cliffs was located, and with the support of the Portland climbing community, a modified diversionary feeding station was deployed near the nest. The station was immediately used by both adult and young kestrels and played a critical role in limiting kestrel predation at the little tern colony. As a result, estimated tern chick mortality due to kestrel predation in 2020 was c. 28% compared to c. 88% in 2019 (when diversionary feeding at Portland west cliffs was not carried out).
  • The colour ringing programme continued despite limited visits to the colony due to poor weather. A further nine adult little terns were colour-ringed along with 24 chicks, and 13 chicks were metal ringed only. Three birds ringed as chicks at the Kilcoole Beach colony in County Wicklow, Eire, were recorded on the Fleet, highlighting the importance of Chesil as a stopover site for little terns on migration
  • A number of measures were introduced to help offset Covid restrictions. A light-sensitive meter was incorporated into the anti-predator fence, removing the need for wardens to be on site late at night and early in the morning. It worked well and the project will now incorporate the switch as a standard measure.

Looking forward into 2021, we will seek consent to enlarge the area of the anti-predator fence to provide greater protection for the expanding colony. We will continue the pilot daytime-only wardening scheme, but include safeguards to prevent further hedgehog predation, including pre-season checks for hedgehog activity near the colony. We will continue the successful feeding of the Portland west cliff kestrels provided we are able to secure safe and effective access. We will also increase protection of the breeding ringed plover population, including deployment of nesting cages to help reduce chick predation by kestrels. All this depends of wardening capacity and funding and will be conditional on the Covid situation in 2021.

For more information about the project please contact:

Richard Archer, Purbeck Priority Landscape Conservation Officer/Chesil Little Tern Recovery Project Manager 

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