Bringing back Choughs to Jersey
Social and economic changes in Jersey over the past 100 years have seen increasing development, agricultural intensification and a move away from traditional mixed farms, with a consequent loss of low intensity arable fields and livestock grazing on marginal areas of the coastline. This has led to the spread of invasive native and non-native species such as Bracken and Hottentot Fig on the island’s coast, causing a loss of good quality habitat for a variety of farmland and heathland birds. The biggest losers have been those birds that were restricted in Jersey to these areas, like Skylark, Linnet, Yellowhammer and European Stonechat.
'Birds on the Edge' (BOTE) is a partnership between the Durrell Wildlife Conservation Trust ('Durrell'), the States of Jersey Department of the Environment and the National Trust for Jersey (NTJ), which started in 2011 to encourage and support the active management of the island's coastal land to restore populations of birds in decline or already locally extinct. The project chose the highly visible and popular Chough as its flagship, to encourage local support for both the restoration project and the Island’s wider environment.
Choughs at Sorel, Jersey, July 2014 (Tim Ransom).
Choughs are found in nearby Brittany and, although some individuals from this small population do wander from their breeding sites, the species has never attempted to recolonise the Channel Islands. BOTE decided to give it a helping hand, and Durrell brought in two breeding pairs from Paradise Park in Cornwall in 2010. The plan was to breed birds at the Durrell Wildlife Park in Jersey, and to release their young into the wild. Paradise Park kindly agreed to supply further captive-bred birds to boost the new population. Not everything, however, goes to plan in a project like this and Durrell’s captive Choughs have not, as yet, successfully fledged young. In 2013 seven sub-adult birds were moved into a purpose built aviary on the Island’s north coast, on NTJ land near Sorel Point.
Chough and Manx Loaghtan sheep at Sorel, Jersey, September 2014 (Liz Corry).
The aviary is sited in an area undergoing habitat management, being grazed by a flock of hardy Manx Loaghtan sheep up to, and over, the cliff top. These sheep have created what appears, to us, to be perfect Chough habitat, and the mix of these two components of the overall project was a seemingly perfect match.
Not to Choughs, though. In August last year we released the first birds, which flew straight to a nearby quarry. Each of the birds carries a radio transmitter attached to its tail and individual rings to differentiate them from Choughs in the UK or Brittany. Weeks of dedicated training before the release to get the Choughs to come for extra food, to ensure that they would not starve as they learned about being wild, eventually paid off and the birds did start returning to the aviary. They never went near the sheep, though!
The Choughs were shut into their aviary over the winter and, joined by three new birds in the spring; the 'soft-release' programme started again in April with these, and five were first released in 2013. Again, the birds rapidly reacquainted themselves with the quarry. Are birds raised within the restricted views of an aviary uncomfortable when introduced to large open spaces and distant horizons?
With two dominant males in the new release flock, conflicts became apparent and two of the birds actually flew away and have not been seen again, with even their radio signals disappearing. The remaining six, including five first released in 2013, slowly adapted and soon began to resemble truly wild birds. While they do return on command for supplementary food, they fly freely along the cliffs or display as a flock high in the Jersey sky. They have even left the quarry behind and now forage among the sheep, just like they are supposed to.
This year, four chicks were hand-reared at the Wildlife Park so that we could trial the release of tame and easily manageable birds. Our methods, if successful, could be used for Chough restoration projects elsewhere, or for other endangered corvid species worldwide. The four chicks were joined by a further six parent-reared birds from Paradise Park. In August, the 10 freshly fledged birds joined the six older, by now well adapted, birds at liberty. While they are no longer shut into their aviary at night, they still return to roost there. By mid-September the flock of 16 Choughs has become a wonderful site and is drawing significant local interest. Exactly as a flagship should, the project can be followed on its own website www.birdsontheedge.org.
We know that there will be many challenges for the restoration project and for the Choughs themselves ahead. The local Peregrine Falcon family, for example, use them as a training tool while teaching their own chicks to hunt. The adult falcons don’t join in and so far the agile Choughs are a match for the young Peregrines. This may not last. We are learning, however, all about Choughs and how to get them into the wild. Older birds raised in the confines of an aviary will adapt to open spaces, but only slowly and with encouragement, while chicks, even when hand-raised, may just take it all in their stride. We need the new chough flock to show us where they want to feed and, hopefully, where they want to nest.
Further birds will be released in the next few years until the population becomes self-supporting. In the meantime, the Choughs are attracting many local visitors and we are one step closer to restoring Jersey’s birdlife.
Choughs on Jerseys north coast with Sark in background (Liz Corry).