Chough report: March 2019

By Liz Corry

It has been all go this March. Sometimes quite literally as some of the choughs have, well, just gone!

Jersey’s chough population plummets

At least that would be the headline if this was a tabloid site. The less drastic approach is to say that several of the choughs have been unaccounted for since January or February depending on the individual. This means that Jersey’s population might have gone from 46 to 37 choughs over a three-month period.

With all the leg ring issues we have reported on recently, it is possible that some birds are going undetected at Sorel. Two birds have been sporting matching leg rings for the past month. We finally managed to determine that one of these is Gilly. Her metal number was read by zooming in on an opportunistic photo. Through process of elimination, the second bird has to be either Duke or Bo. Neither have been seen for a while.

One of two birds sporting the same leg ring combination after losing a coloured ring. Photo by Liz Corry.

To add to the mystery, both Duke and Bo paired up last year forming territories at Sorel and Les Mielles respectively. Duke’s partner is still very much alive and well at Sorel. Although she now appears to be flying around in a trio with two others. Bo and his partner, Mary, were not identified at Sorel throughout the entire month. Have they permanently moved to the southwest of the Island? Or, has something happened to one or both birds?

Mystery disappearances have also affected two pairs from Ronez Quarry that shared the same building. Our beloved Bean and normally easy to spot Q (bright pink ring) have a zero attendance record for March. Their partners are regularly turning up to the supplemental feed so what does that mean? Did they decide to ditch their trademark monogamous ways and elope to a different part of the Island? Are they dead? Has Bean become agoraphobic and can no longer leave her roost?

What we do know is that we have new pairings generating both good and bad news.

Breeding pairs for 2019

We are not 100% clear on all our pairings this year due to the confusion over which birds are alive and dead. For example, Bean’s partner Kevin is now followed everywhere by two foster-reared females Ubè and Wally. This lends itself to the theory that Bean is no longer at Sorel (or Jersey). Likewise, Pyrrho who was with Duke last year, now appears to hang out with another pair. This pair is one of our new couplings Skywalker and Zennor.

There are a few new pairs at Sorel this breeding season including Skywalker, released last year, and Zennor. Photo by Liz Corry.

On 4th March, Skywalker was observed at Sorel with wool. It wasn’t entirely clear if he was collecting the wool or if the wind had blown it across his face. He carried it around for a bit ultimately ditching it for the supplemental feed. On the same day we found bits of wool inside the aviary – a sign that the pairs had begun lining their nest.

At this stage, we think there are ten pairs and two groups of three attempting to nest at various sites around Jersey. I have to say it….

West is best?

You are now just as likely to see choughs at Les Landes, Grosnez, or Plémont as you are at Sorel these days. There is at least one pair nesting out west, possibly more given the difficulty in tracking individuals.

We have had lots of reports in from the National Trust, States of Jersey rangers, and Durrell staff on their days off.

Choughs hanging out at Plémont. Photo by John Parkes, National Trust for Jersey.

Grantez is being highlighted as a foraging site and/or fly over route. Not to be confused with Grosnez, which is starting to look hopeful as a potential nesting territory. It also appears to be the perfect ‘playground’ for the choughs to practice their aerial acrobatics whilst annoying the resident fulmar population. Note that fulmars (who are very good at spitting) and choughs aren’t always the best of neighbours.

The perils of plastic

We had to catch up Betty this month when she was spotted at the aviary with yellow nylon wire wrapped around her right foot. Betty had most likely picked this up whilst looking for nest liner. Luckily, we were able to trap her in the aviary relatively quickly. It still required a two-day wait whilst hatches were fixed – yep they jammed again – but we cut the material off before it could do any damage.

Betty was caught up in March to remove material wrapped around her foot. Photo by Liz Corry.

Whilst in the hand, there was the opportunity to clear up confusion over a DNA test taken when Betty was a chick. The original sexing result was questioned by the DNA testing company due to an admin error. Betty’s recent behaviour and body weight of 350g implied she was a he. A new DNA sample was taken and sent to the UK. The result came back as a definite male.

This is great news as Betty is paired up with Gilly (female) and this year they look set to nest for the first time.

On a side note, their relationship meant that Gilly followed Betty into the aviary when we trapped him. This allowed us to catch Gilly as well and replace her missing green ring.

Zoo choughs show a promising start

Jersey Zoo has a new pairing this year of Tristan and Pendragon (Penny for short). They are in fact our only pair now due to the sad loss of birds last year. Both are experienced breeders but this will be their first season together.

So far so good. They have been busy adding material to the nest box. Hopefully there will be eggs by April. Staff are monitoring progress closely via the nest cam.

The new pair at Jersey Zoo started building a nest in March. Photo by Liz Corry.

Skills-sharing on a global level

Each year the Durrell Conservation Academy runs the Durrell Endangered Species Management course. The participants, affectionately known as DESMANS, come to Jersey from all over the world to learn practical conservation skills which they can then take back and apply to projects in their own countries.

Birds On The Edge is incorporated into one of their modules where they learn skills in radio-tracking, distance sampling, reintroduction practices, and broaden their knowledge in conservation management.

DESMANS learning how to radio-track at Jersey Zoo. Photo by Izabela Barata.

This month they visited Sorel to see the project up close and personal. Instead of a stuffy indoor lecture, they were treated to my ramblings on about Birds On The Edge and how the choughs have returned to Jersey. They were very impressed with the choughs although the friendly Manx sheep clearly stole the show.

DESMANS 2019 with course leader Tim Wright and facilitator Izabela Barata at Sorel. Photo by Liz Purgal.

 

10 thoughts on “Chough report: March 2019

  1. Once again..an informative, well documented report full of the light hearted humour, from Liz, that we have always enjoyed….great to see the Desmans experiencing ‘hands on’ experience at Sorel….Despite the mentioned possible ‘losses’ the Project is definitely a success…well done everyone.

    • Hiya

      I think that the most obvious risk is peregrine and we know of one definite take. Some others have vanished and the peregrines may know where they went. However, I guess that worldwide choughs will always encounter peregrines so they are well adapted and there are pairs of falcons close to Sorel so the two species know each other well. There are buzzards and marsh harriers around Sorel all day, every day, but the choughs just want to play with them. Of other birds known to be a threat at times, ravens don’t seem interested and the choughs may only now be encountering fulmars. If, as we hope, the choughs do move onto the cliffs they may meet ravens and fulmars more than they would in the quarry buildings. Feral ferrets and cats may be a threat to birds on the ground. Otherwise I think probably starvation, water troughs, being mistaken for carrion crows etc.

      Glyn

      • Thanks Glyn. Very interesting. As you probably know, we had one of our very first released Hayle Choughs shot “I thought it was just a crow”. The farmer’s fed it to his ferret, the ring was found as proof! Keep up the great work. Good luck to you all.

  2. I watched two choughs collecting hair left by the horses rolling in the field at sorel. Maybe more warm lining for their nests at the quarry.

    • On Skomer Island in the 80s, when lagging underground trenched pipework with bright yellow fibreglass material, choughs were taking this for nesting material. When the trench was infilled the next day the birds were seen furiously digging at the site to get down to this obviously highly desirable stuff!

      • I love it! The first year that Jersey’s nested in the Quarry (2015) they took some sort of foam lagging off pipes in or on the buildings to add to their nests. We apologised on their behalf!

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