By Liz Corry
It was a very cold, wet and windy start to the new year bringing with it several challenges for the choughs at Sorel. Their primary concern, as always, was to find food to keep them fueled throughout the bitter and blustery days. With the grazed land saturated by rain water, insects were hard to come by. This might explain why they started making regular visits to the conservation fields. An untapped source of insects?
The cliff face around Devil’s Hole, where the water runs off rather than collects, also proved popular exemplified by their muddy bills and heads.
Fortunately there was only one day of ground frost which disappeared fairly quickly. Chough bills are efficient digging tools, but they are not tough enough to break hard ground. An unseasonal or prolonged period of ground frost can lead to starvation and is often detrimental to wild chough populations.
Jersey experiences another kind of ‘ground frost’ for birds at this time of year. Jersey Royals are planted in January and the farmers cover their crops with protective plastic sheeting. The sheeting is largely to protect from ground frost and encourage growth, but also stops birds stealing or damaging potatoes. Of course the choughs are not interested in vegetables they want the insects in the soil. When the young choughs flew over to Crabbé this month after a short spell away you can only imagine what was going through their minds the first time they flew over the fields.
Jersey’s chough population became a bit more reliant on the supplemental feeds at the aviary. This is where there next challenge awaited. How to fly through release hatches into the aviary with 40+ mph tailwinds or cross winds without smacking into the frame-work? Those that did risk actual life and limb demonstrated just how aeronautically skilled this species is.
For the likes of Ormer and other less confident individuals, the team started placing food bowls on the ground outside of the aviary. For those inside who then found themselves struggling to stay grounded on the tables, the bowls were placed in more sheltered positions.
There have been a few times this month when the weather has been so bad, the group fail to turn up for the aviary feed. Opting instead to stay sheltered on the cliffs by Devil’s Hole or in the dry, warm quarry buildings. Who can blame them?
There is growing concern for the aviary itself after three winters out on the cliffs (four if you include whilst it was being built). One of the shelter stands became dislodged from the framework after overnight gales. The integrity of the plywood roof is beginning to give, reducing the amount of dry shelter spots for the birds when they roost and keeping food bowls dry. Ideally a new bitumen-panel roof needs to be fitted with guttering to collect rainwater (5-10 litres of water is carried to the site each day). This cannot be done without finding funding first. We estimate costs to be around £500 or less if we can find reclaimed materials. Then, all we need is a day when the winds won’t blow the builder off the roof!
That being said, January did experience a few sun-blessed days much to the excitement of the choughs who took full advantage of the calmer weather. Visitors to Sorel will have seen amazing aerial displays from the group. Some of the younger males have started displaying around the breeding females involving lots of tail flicking and running around like a scene from a Benny Hill sketch.
January is the month when the choughs start planning for the upcoming breeding season. Nest prospecting (weather permitting) and looking for potential partners. We switched their supplemental food to the breeding diet which means more protein and calcium. The captive pairs at the Wildlife Park will switch to their breeding diet when they move from the flocking aviary into their separate breeding aviaries.
We have tried to see if the choughs would take a pelleted diet. The expected cost of supplemental feeding for 2016 is approximately £3,000. An all-in-one pelleted diet could reduce this as long as it is not at the expense of the birds’ nutritional needs. So far we haven’t found one which the birds will not either ignore, flick out of the dish, or jump from in fear. Yes that actually happened!
Just for fun here are two of the youngsters searching for insects in a slightly unusual way…..
January was looking set to be a relatively mundane month to report back on. That was until the morning of the 31st when Durrell student, Nicci, was out on radio-tracking duties. The choughs were spread out as per foraging around Sorel and Mourier Valley. There are seven birds whose daily movements are being tracked with proximities of the other fifteen birds in relation to those focal birds also logged. Not all twenty-two need to be accounted for at each session, but they usually are as the group stick together out of the breeding season. ‘Brunch’ at the aviary is when we expect to see all of the birds at this time of year. On this occasion there were only twenty-one. Nicci’s concern started to grow over the course of the afternoon as there was still one bird unaccounted for. At the afternoon feed she could still only count twenty-one. Mentally ticking off leg rings from the list time and time again Nicci reported back to the team that Dusty’s mum, Blue, was missing.
She was last seen the day before, an hour before roost. Her and her partner now roost in the aviary, as opposed to the quarry, where the only threat at night would be from a feral ferret or cat. In which case you would expect signs of intrusion at the aviary and the group to be behaving differently the following morning. Nothing. Was she off exploring for nest sites without her partner? Had a peregrine snatched her? Would she reappear the next morning? Only time, and February’s report, will tell.