By Liz Corry In July’s monthly report we revealed that Durrell’s hand-reared chicks had taken to the skies for the first time. A first for the birds and the project as no chough this young has been released into the wild for a re-introduction project before. Summing up what happened over the twelve days of releases into a couple of paragraphs doesn’t really do it justice. So, we thought we should show you in a bit more detail the antics of Dingle and the girls.
In the days leading up to the first release the chicks were put through their paces. Making sure they knew where to go when they heard the whistle for food; flying lengths of the aviary at least three times a day; squat jumps and press ups morning and night…Ok not the last bit. In fact the physical aspect of their training would only really be achieved once they were out and being tested by the elements. Flight in the polytunnel has its limitations. What the chicks really needed to focus on was learning how the adults go about day to day living. Watching them respond to the keeper, their foraging techniques, reactions to predators and other potential threats. All behaviours key to survival. Again this does have its limitations when you are confined to an aviary. But with the adults regularly visiting the aviary they had plenty of opportunity to pick up the basics.
The problem we faced was that the chicks became so obsessed with the adults that when the adults were not at the aviary the chicks would just take naps in the roost boxes and not want to train with us. To add to our exasperation we wanted to release the chicks when the adults were not around, i.e. when they were in the quarry. We wanted the chicks to learn how to go in and out of the aviary at their own pace. More importantly, we didn’t want the adults around when it was time to shut the chicks in.
They would either create a distraction or end up getting locked in with the chicks. So on the day of the first release we waited for the adults to head to the quarry, opened the hatches, and waited. And waited… The chicks had disappeared into their favourite roost box just inches from the hatches. A change of tactic was clearly needed after twenty minutes of no activity. We called the chicks down for a meagre amount of insects at the other end of the aviary. The idea being they would emerge, become active and then see the hatches open and start exploring. This worked and it didn’t take too long for one of them to go outside. With baited breath we clung to every heartbeat wondering what would happen. How high would they fly? How far would they go? Who would they meet? We didn’t account for Dingle hopping down to the floor and taking a bath in the adult’s water tray! Obviously very content.
Inevitably the adults returned to the aviary before we were ready to call the chicks back inside. The youngsters showed a lot more excitement than the adults whose single focus was food. That motivation kept everyone close to the aviary. The adults perched on the aviary looking on as the chicks would occasionally launch themselves from the netting and whizz around the aviary. When it came time to close the hatches the adults were inside on the whistle before the chicks. Likewise as we approached to close the hatches the adults were the first out. Knowing full well closure meant no evening playtime in the quarry, they were not willing to stay. The chicks on the other hand continued eating oblivious to what was occurring. The adults stayed nearby so when the whistle was blown to reward the group with their favourite treat they flew in and landed back on the aviary. Their calm obedience was a testament to how well they have adapted to the wild. It was definitely one of the most rewarding days for everyone on the chough team. The next day was pretty much the same. The only exception being the arrival of the peregrine family minutes after the hatches were opened. They had been a common feature of Sorel in the preceding days. The young peregrines saw the adult choughs as target practice. They would swoop down and chase the birds. Unlike the neighbouring crows and magpies, the choughs would always stick together flying in formation. I think this helped as no chough could be picked out as an easy target. The choughs could also play the ace card of returning to the aviary and fading into the background of the black shelves and netting. The chicks first ‘encounter’ in the wild with the peregrines involved them staring up from the external shelves observing the commotion above. After opening the hatches the chicks were still inside when I heard distant chough calls from behind the aviary. On the horizon the image of five dots very quickly formed into five choughs flying with determination towards the aviary. Scanning the skies for the sixth chough revealed two interweaving shapes approaching from inland, one a chough, the second definitely a peregrine. Through grit and determination (and a bit of cockiness when she retaliated) she made it back to the aviary unscathed along with the other five who had landed sometime before. The chicks by this point had already flown back inside into the farthest depths of the aviary. We locked them in half of the tunnel and allowed the adults in the other half for respite until the peregrine left. On another occasion two juvenile peregrines chased the group flying no more than 20ft above my head whilst sat by the open hatches. That event, as you can imagine was a blur at the time. And after! Even the frantic camera clicking pointing in hope at the sky didn’t do it justice.
It wasn’t always that easy to get the chicks back inside the aviary. Bean’s behaviour on the fifth night of releasing was a prime example. To be fair to her, the afternoon had been quite challenging. Minutes after the hatches had opened the choughs were being harassed by a peregrine so the chicks were locked back in until it left (I realise at some point there will be losses due to predation, but not at the aviary, not on my watch!). Then when they were allowed out again the wind picked up. For a species that nests in sea caves and lives near the cliffs a bit of wind should not be a problem. However, for a soft release, a cross wind or worse, one that propels them towards a small opening in a wooden frame, can be challenging if they haven’t mastered all the tricks of flight. It wasn’t just Bean having difficulties that day.
Then again my sympathies diminished after one of many failed attempts to coax her back inside. I had walked them down from the sheds to the hatches by talking nicely and waving insects in their faces. Hand-reared chicks are very compliant that way. When they saw the hatches they started to hop inside one by one heading for the food dishes. All except Bean who stumbled at the last hurdle. All she had to do was cross from one shelf to the other a few inches away. Max had even put up a perch that morning to bridge the gap. She stared at me, stared at the gap, then flew back to the other end of the aviary and sat above the other three chicks feeding below.
In this situation the protocol is to shut in the birds you can, lock them into one section, and hope they will act as a lure to encourage the straggler(s) in. There comes a point when the chough left outside no longer cares about food and just worries about where it will roost for the night. That’s when we have to set aside the training methods and just sit guarding them patiently until they find their way back. Bean herself seemed relatively calm. She spent time preening and sitting next to the other chicks (well just above them to be specific). She did explore the roof and fly back and forth trying to find a way in. She even sat in the external roost boxes once or twice. Never once did she go to the hatches. As the sun sank below the cliff tops she was visibly more agitated and starting darting away from the aviary calling to the others. She finally settled, not in the external roost boxes, but out on the netting just next to the roost box the chicks were sleeping in. We left her just before 10pm and I returned at 5.30am before the sun was up, to find her in exactly the same spot.
Much to my relief she was alive although very sleepy. To be fair the other three had not really woken up either. I was worried that the night out and stress of yesterday had taken its toll. Luckily all she needed was a soak in the sun. As it started to rise above the hill she moved to an external roost box and sat preening in the full sun. Soon she had made her own way back inside and by 6.38 am she was reunited with the others. The soft release continued for a further four nights. The chicks spent their time outside foraging with the adults in amongst the sheep, exploring the cliff tops and playing on the air currents. They have certainly explored further than the adults ever did at this stage in the soft release process. It is a really positive sign for things yet to come.
We had to put the releases on hold whilst we went to collect six new birds from Paradise Park. After which point all the aviary birds would be in quarantine lockdown for thirty days minimum. You can imagine the tension then on the last night before our departure when we let the chicks out at 3pm. Stress levels, already above average, peaked when the adults decided it was time to head back to the quarry and the chicks followed. In flight there was an obvious split between the two groups as the chicks lagged behind. From our view point we think they made it as far as the car park. From their position they would have been able to see the quarry. Whether it was the moving cars, the site of the quarry, or general lethargy the chicks changed their minds turned around and flew straight back to the aviary. I don’t think any of us could have predicted how well this round of soft releases has gone. Let’s hope the next phase with the parent-reared chicks will be just as successful.