A newly published study has estimated that the global great black-backed gull population has almost halved within the past four decades.
Using the most recent population counts from across the species’ range, Sam Langlois Lopez and his colleagues analysed population trends at a global, continental, and national scale between 1985 and 2021.
Their results confirmed recent concerns among conservationists that great black-backed gull has been faring badly at both local and regional scales, with widespread declines noted across its North American and European range. The global population is estimated to have declined by up to 48% over the study period from an estimated 291,000 breeding pairs in 1985 to 152,000-165,000 breeding pairs in 2021.
The losses have been most pronounced in North American populations, where the species may have declined by up to 68% since 1985. Although faring comparatively better, European populations have still decreased by up to 28% over the same period.
While there were populations that showed growth between 1985 and 2021, these tended to be smaller and/or were present within a larger state or country where most populations declined. Most increases were recorded in populations on the periphery of great black-backed gull’s range, or in areas that have been recently colonised. These include Spain, Germany and The Netherlands in Europe, as well as North Carolina and Virginia in the US.
The reasons for the decrease are not clear, although are suspected in part to be related to a reduction in the availability of discards from the fishing industry, as well as an overall decline in food availability in the natural environment.
As a result of the findings, Langlois and his colleagues recommend that great black-backed gull should be uplisted from Least Concern to Vulnerable on the IUCN Red List of Threatened Species under criterion A2 (an estimated reduction in population size of more than 30% over three generations).
Read Global population and conservation status of the Great Black-backed Gull Larus marinushere
Plémont bay – a new territory for the choughs. Photo by Liz Corry.
By Liz Corry
A lot of ups and downs this month for the Channel Island choughs; literally in some cases! The nests have fledged with some surprising outcomes. Whilst the chicks were escaping their nests, I escaped the Island to Slovenia to talk all about choughs to Germans.
In a first, on record, a wild-hatched chough has fledged at Plémont! The pair responsible were on their second season of trying and are the first to successfully breed away from Sorel.
The success is largely due to the pair’s ability to find food in the wild. They have not been seen at the supplemental feeds for a long time implying they don’t need it. Instead they forage around Plémont, Grosnez, and Les Landes.
The Plémont chick is a fast learner. It even picked up some cave art skills! Photo by Liz Corry.
It has been quite challenging to keep up with the youngster. When first bouldering outside of the nest it would hide behind rocks when mum and dad were off finding food. We didn’t manage to get any clear photos of it at this age.
Born into the wind, the chick was quick to develop its flying skills. None of this hanging around the quarry clinging to the safety of girders and stairways.
There have been a few sightings of the family at Plémont. We probably won’t be able to give the chick an identity (leg rings, DNA sexing) until they start returning to the Sorel feeds. If they return!
The ones that got away
We returned to the quarry on 4th June to ring chicks too young to ring when we visited last month. The first nest belonged to Red and Dingle using a box in the asphalt plant. You may remember they had two young chicks. Now there were three!
Licensed ringer Dave Buxton discovered three chicks in the nest- box. Photo by Liz Corry.
The newcomer was 23 grams lighter than it’s siblings. Having hatched last, it had time to catch up. On 25th June the quarry reported all three chicks had fledged with parents attentive as ever.
Staff soon began to realise one of the chicks was in trouble. Whilst two had positioned themselves on the purlins of the building, the third was out and exposed to the risk of mechanical harm. Staff left doors to the building open hoping the parents would encourage the chick back to safety. Apparently the parents were shouting at it quite a lot; one assumes that is what they were trying to do!
Onsite CCTV allowed staff to keep watch on the chick; it appeared to be doing ok. After two days it wasn’t moving – at all. Sadly it had died. A post-mortem revealed a healed fracture in one wing. An underlying reason for its restricted movements around the asphalt plant? The interesting find was that this wasn’t the ‘runt’, but one of the older, larger chicks.
Choughs are full of surprises. When we went to ring Kevin and Wally’s brood on the 4th we found they had lost a chick pre-fledge. Disheartening as it was they had made up for it in size. They were huge! We remembered tiny, half-naked things. These were fully-feathered beasts. I’m pretty sure there is no literature on choughs feeding protein shakes to their chicks. We certainly didn’t find a nutribullet secreted in the building framework. Whatever they’ve been fed, the chicks survived and by the end of the month they were frequenting the Sorel aviary.
One of Kevin and Wally’s chicks having leg rings fitted. Photo by Liz Corry.
Other fledging news
We are pretty certain that all the chicks have now fledged. Unless any undetected nests along the north coast wish to make a claim – please do so now.
Proud to say we have new choughs flying around Jersey’s north coast from six different families. Somewhat disheartening to know there were broods or individuals that didn’t make it. From what we have seen it is simply a result of life in the wild.
One reason for loss is inter-specific competition within the quarry. I had a joyous moment mid-June watching Green and Black’s recently fledged trio being fed on the east side – where we used to supplemental feed released choughs.
Imagine my surprise as watching through the scope I saw a herring gull appear from nowhere and pin down a chick by the throat. Lots of shouting and wing slapping ensued.
Surprise attack by gulls on the recently fledged chough family. Photo by Liz Corry.
A pair of herring gulls pin down one of the chough chicks by the throat. Photo by Liz Corry.
A second gull joined in as did all the choughs in the quarry at the time. The chick managed to escape although I imagine it sustained injuries. Since that day we have only seen the parents with one chick.
The gull’s actions were not fully unjustified. They had a chick about two metres away from where the chough family had been hanging out. They were just doing their job of being good parents. With more choughs and increasing numbers of gull nests we are likely to see more of this behaviour.
Taken several days after the attack, this cute ball of fluff explains what the fight was about. Photo by Liz Corry.
An interesting anecdote from this event was how the other choughs reacted. They didn’t physically attack the gulls (a couple tried) it was more of an audible attack. Once the fighting stopped and one gull returned to their nest, the choughs stayed with the chough family almost like a standoff.
When it looked like matters had calmed down the choughs began breaking away going about their business. One pair returned to their nest in the lower quarry. Choughs truly are a social species.
Thankfully choughs raised in the zoo do not need concern themselves with gulls, peregrines, or dangerous rock-crushing machinery. Just their dad!
Tristan remained separated from Penny and the two chicks throughout June. The chicks look really well and have now fledged. We will look at moving Tristan back soon along with Gianna for the summer.
Dobrodošli v Sloveniji ⁄ Welcome to Slovenia
I was invited to talk at Monticola’s annual meeting held, this year, in the Julian Alps, Slovenia from 11th to 16th June. Monticola is an association of amateur and professional ornithologists specialising in alpine species.
The Julian Alps in Slovenia were once home to red-billed choughs. Photo by Liz Corry.
This year’s focus was to discuss the feasibility of reintroducing red-billed choughs to Slovenia. Red-billed choughs disappeared mid-twentieth century from Slovenia (yellow-billed choughs are still numerous). Hunting is attributed to much of the loss. Change in land use and effects of pesticides and/or cattle worming are likely to be the other major players. A large proportion of alpine pastures in the Julian Alps have been lost to the encroaching commercial forest.
Caûvette the chough surveying the habitat. Photo by Liz Corry.
Various day time excursions were planned along with evening talks. Members of BirdLife Slovenia (DOPPS) talked about their work and joined me for a scary panel discussion on reintroducing the chough. I say scary, not because of the stature or responsibility being on this panel. Rather because it was in German…and Slovenian!
Tomaz Mihelic, BirdLife Slovenia, gave talks about monitoring and conservation of various Slovenian species. Photo by Liz Corry.
BirdLife Slovenia don’t just work with birds. Photo by Liz Corry.
Monticola members are mainly German or Swiss-German. To add to the fun, the German for red-billed chough is Alpenkräuhe which is not the same as the Alpine chough known in English as yellow-billed choughs.
Promo material handed out to Monticola members. Photo by Liz Corry.
Thankfully I had the lovely Johannes and Arnette Denkinger who took me under their wing. Johannes had invited me to speak after reading about Birds On The Edge. It has been his passion for many years to see the return of the red-billed choughs to the eastern Alps.
Birdlife Slovenia did not appear to be against the idea, but raised the realistic challenge of limited resources and existing government priorities. Using evidence from Jersey, and Durrell’s ethos, we all agreed there was scope to create a similar project to Birds On The Edge in Slovenia whereby the focus is restoring alpine pastures. Support is already there within the German zoo community where a captive-breeding programme has been initiated. Tiergarten Nuernburg are leading the work and have invested in habitat feasibility studies.
At the end of the day this needs the people of Slovenia to be behind it. A challenge Johannes is prepared to take on!
Caûvette the chough taking a break at Lake Bohinji. Photo by Liz Corry.
Insurance Corporation Conservation Awards 2019
Congratulations to Birds On The Edge partner the National Trust for Jersey who were awarded runner’s up prize for their conservation meadow at The Elms. The winners were SCOOP The Sustainable Cooperative for their soon to launch ‘Re-Wild my Plate’ initiative.
Glyn Young presenting Kaspar Wimberley of SCOOP with first prize at this years Insurance Corporation Conservation Awards.
Glyn Young was one of the judges and presented the awards at a ceremony held at the Pomme D’or Hotel. I gave a short presentation explaining how we spent last year’s award money supporting the chough project. We must state for the record there was no vote rigging!