PART 1. Seabirds
The ABO was able to make a significant return by way of our annual contribution to the States of Alderney RAMSAR program despite the obvious difficulties that this year presented.
Our observatory–led seabird ringing research trips have been extremely popular with UK bird ringerssince the ABO began leading this part of the program in 2016. The seabird ringing program on Alderney and its offshore islets began in 1945, undertaken for the Channel Islands Bird Ringing Scheme almost exclusively by bird ringers travelling from Guernsey to complete this important research work.
Alderney has had its own resident bird ringers qualified to manage the programme through the ABO since 2016. We have strived to develop and refine methods and best practice for obtaining data and minimising disturbance of our seabird colonies with each passing year.
Increasing numbers of UK ringers now travel to Alderney annually to assist with this work adding skills and experience to the wealth of knowledgecontributed by Channel Islanders.
Each of the scheduled trips for 2020 was fully booked with licenced bird ringers, an exciting, rich mix of experience and enthusiasm set to gather data in researching and understanding our seabird colonies. Alas Covid-19 saw forced blanket cancellation of our visiting bird ringers from the UK. Things looked bleak in terms of any offshore seabird ringing for this ill-fated year.
However, we were able to adapt and complete some of the most important elements of the RAMSAR seabird ringing program thanks to the small team of Channel Islands-based ringers.
The ringing of Gannet chicks on Les Etacs has been carried out by representatives of the Channel Islands Bird Ringing Scheme almost annually since 1945. Thelocal seabird ringers who have completed the task many times expressed a feeling that it is no longer safe for bird ringers to climb this rock due to the density of the colony and size of the nests.
A review of how to ring Gannet chicks on Les Etacshas been suggested and options to improve the safety of birds and ringers are being considered. Tons of nylon fishing gear is taken to the colony with seaweed nesting-material each season. Chicks and adults get caught in it and the team is often able to free them during the visits, making them all the more useful.
Ortac to the west of Les Etacs is home to a slightly smaller Gannet colony which is altogether a much easier proposition. Although landing can be tricky,moving around the rock is significantly easier.
Sadly, the timing of a local virus lockdown on Alderney prevented us visiting Little Burhou to ring the Cormorant colony. Visiting Ortac and the small auk colony on Coq Lihou were sacrificed this year in favour of pooling all available resources into a focussed effort ringing the Storm Petrel and Lesser Black–backed Gull colonies on the Island of Burhou.
More than 500 Storm Petrels were ringed over two consecutive nights, 17 and 18 July. The first-choicesite for ringing Storm Petrels if conditions allow is at the north–east end of the island at a dedicated location where just two 18-meter nets are deployed.This long-established site allows continuity of annual records and data returned.
The first Petrels begin to arrive soon after dusk (around 10:15pm) on the first night. This is a large colony, and two nets are quite sufficient to keep a team of five experienced ringers employed until 4am when we finish about an hour ahead of dawn. We processed 254 new birds, 29 local retraps and two overseas controls this year.
The weather conditions were good on the second night and we moved a short distance to the other dedicated location in the north west corner of Burhouagain to obtain valuable long-term data. Redeploying our nets we processed 259 new birds, 42 local retrapsand again two foreign controls. The winds began to get up around 3am and the decision was made to finish a little ahead of schedule.
A total of 588 Storm Petrels were processed, 513 new birds, 71 re-traps and 4 foreign controls (three UK and one French) over the two nights.
The first bird to be ringed, however, was a single Rock Pipit. This species does exceptionally well breeding on Burhou. There are well in excess of 50 individuals present in July each year. Rock Pipit is a species that has received precious little international research attention resulting in minimal baseline data. One scientific authority even referred to it as ‘The Grey Man’ of British birds.
Undoubtedly there is local dispersal of Rock Pipits across the Channel Islands besides the more significant migration movements. Though not a rare bird, it is arguably as important to understand why a species is doing well as it is to learn why they may be in decline. The ABO had a request to study these birds rejected by the Alderney Ramsar committee and we hope that a new independent panel of experts, set up to oversee all aspects of conservation and wildlife on Alderney, will recognise the opportunity to obtain data on these ‘forgotten’ birds.
Exciting news received by the Channel Islands ringing scheme this year was of a Storm Petrel ringed on Burhou, 20 July 2014, by Guernsey’s Chris Mourant. The bird was recorded alive and well 382km north during a ringing session on 22 July 2020 at Bardsey Bird Observatory (Great Britain, Gwynedd, Wales). The time elapsed was 6 years 2 days.
Further birds ringed on Burhou by the ABO teams in previous years processed this year outside the Channel Islands are:
– processed 30/07/2020 at Gwennap Head, Cornwall, Great Britain
– processed 19/06/2020 at Plemont Point, St Ouen, Jersey, Channel Islands
This year’s four foreign controls (birds processed on Burhou this year originally ringed outside the Channel Islands) are as follows:
Burhou 18 July
– originally ringed 26/06/2019 – Portland Bill, Dorset, UK – – ~ originally ringed 06/07/2019 – Gwennap Head, Cornwall, UK
Burhou 19 July
– originally ringed 01/08/2019 –Skokholm Island, Pembrokeshire, UK ~ originally ringed 05/06/2018 – Le Conque, Finistère,
In terms of longevity, the oldest birds re-trapped were two individuals originally ringed on Burhou in 2006.
Not wanting to waste precious time on Burhou, the team got on with colour–ringing chicks in the Lesser Back–backed Gull colony during daylight. This was my fifth year observing the productivity of this species and there was little doubt that a bumper year was in progress. In one small area of the colony where we have previously processed a maximum of 20 chicks in a good year, we found 47 birds.
There was, however, evidence of a marked increase in casualties with eight deceased chicks in the same area where in previous years we have recorded a maximum of three. There were fewer addled eggs located this year, only four. Overall, more birds were closer to free flying indicating that the dates for this research work should not be extended (if this is to be considered an average year). It was too hot during the day and scheduled work in the Gull colony wasdelayed until late afternoon rather than risk exposing chicks to the sun.
Combining the Gull and Petrel research was a great success given the difficulties arising from the COVID-19 situation.
Having considered disturbance of the colonies the ABO recommends the combined approach of a single Petrel / Gull visit as preferable. Indeed, a three–night effort would be ideal in terms of gathering data on these two target species. The benefits of less disturbance in a single visit were clear.
Being able to ring Storm Petrels on two consecutive nights was unusual. Winds often prevent ringing in exposed sites. An extra night would greatly improvethe chances of a good annual data return. It will be interesting to see the Gull population estimates from this year’s RAMSAR officer given our teams’observations and colony size estimates.
Two Herring Gull chicks and two Shag chicks were chanced upon and ringed. A further Lesser Black-backed Gull chick that wandered into our camp HQ on 19th was also ringed.
Field observations of passing migrants included a Honey Buzzard, Grey Heron and Common Sandpiper.
The accommodation hut on Burhou – Photo, Dan Scott
Burhou Island just NW of mainland Alderney
Other seabirds ringed on Alderney outside the RAMSAR site this year were two Herring Gull chicksand 28 Storm Petrels (22 new, 6 retraps).
Our mainland Alderney Storm Petrel ringing efforts produced the earliest record of the species (22 May2019). This year we continued to look at Petrel arrival dates and despite efforts from mid-May in good conditions our first birds were processed on 15 June.
Storm Petrel ringing on Alderney’s NE coast. The amount of white on the underwing can often determine the sex of this species, in this case above, substantial white indicates a male. Photo JH.