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Southern Ground Hornbills (Bucorvus Leadbeateri)
At Cricket St Thomas Wildlife Park, Dorset, England
By Jane Finch
A Summer of Southerns
The southern ground hornbill experience
At Cricket St Thomas Wildlife Park, there are two adult Southern Ground Hornbills, Jeremy and Jemima. Jeremy was wild-caught and came to the Park in January 2003 as a juvenile just starting to colour-up, so is now about 6 or 7 years old. Jemima was also wild-caught and came to us in January 2001 at about 10 years old, so is now roughly 16. Their enclosure is approximately 80x50x14ft high and made of weld mesh with a soft netting roof. It is built on a grassy bank, enclosing pre-existing trees and shrubs. These offer good protection from the elements. There are also roughly a dozen artificial perching sites added. The nest box is 2 ½ x2 ½ x3 ft in dimensions and has an entrance hold near the top of the box, allowing a drop of roughly 2 ft to the bottom of the box. It has a removable roof, which is covered with roofing felt. The nest is lined with a mixture of woodchip and hay, although other substrates are left and collected by the adult birds. A large sand-tray has been built on to the side of the slope for the birds to bathe in, and it also allows keepers to add mealworms which can be foraged for. Large piles of leaf-litter and tree cuttings are also available for this type of enrichment.
Jemima is a little reticent about showing herself and Jeremy is downright scared of his own shadow! He seems to constantly hide in the corners, only showing himself when he is absolutely sure that there is nobody to see him, with the occasional haphazard ‘fly-past’ if he happens to get spooked by something (possibly merely a rustle in the grass!). He doesn’t even bother to show himself at feed times. So, therefore, the chances of him being bold enough to approach Jemima for breeding purposes seemed somewhat limited, if not impossible.
But…………..Jemima is a very pretty lady, and timid Jeremy just couldn’t resist her!
And here lies the tale…………
In the natural environment in the wild, a group would consist of an Alpha male and female, and several other (usually male) helpers. The female would normally lay two eggs , the second of which always dies if the first hatches. So the group would rally around attempting to rear the single chick, usually against the odds, the success rate being approximately one chick raised to adulthood every 9 years. Factors for this low reproduction rate include: -
Loss of habitat due to farming Indirect poisoning/trapping Shooting Loss of large nesting trees Exotic bird trading
So then………back to Jeremy and Jemima.
In 2005, eggs were found in the nest box for the first time since they had been paired up, but they had been destroyed, whether deliberately or accidentally was unknown, and it wasn’t known if they were fertile or not. As this was both their first time as potential parents, it may be that they were destroyed through inexperience.
On the 6th March 2006, I noticed that Jemima was hiding in her nest, and didn’t come out for breakfast as usual. On further inspection, I discovered that she had indeed laid an egg. Due to the unfortunate events of the previous year, it was decided to remove the egg and set it for incubation, and basically see what happened. It was incubated in a moving-air incubator, at 37.7 degrees Celsius and at 58-60% humidity. Four days later on the 10th March she laid her second egg of the clutch, which was also removed and incubated. Both eggs were replaced with dummy eggs, which she wasn’t fooled by and ‘buried’ in her nest about 10 days later. So we waited……and on approximately day 8 of incubation, the first egg was candled and revealed nothing at all. So we waited for 4 days, and candled the second egg and found it to be fertile. So, Jeremy had done his job after all. The waiting continued, with the egg being removed from the incubator when it started pipping, and put in the hatcher with humidity increased to 80%.
And this is where inexperience kicked in.
We had absolutely no experience or knowledge of rearing SGH chicks, and although I looked on the internet, there was little detailed information on what foods to give and how often etc.
The chick, named Bertie, was left in the hatcher at 34 degrees with humidity reduced . He weighed in at 57g. He was left for 12 hours to allow him to digest the yolk and was then fed pinkie mice. He went home with one of our Senior Keepers, Matt Board for the first 11 days to settle him. Then on day 12, he came to me to be looked after. At this point we had been happily feeding him pinkies, day-old chick wings, mice tails, chopped fluffs and mealworms. We dipped his food in water, and gave water from a syringe.
The very next day, I noticed some laboured breathing, and for the next few days he was put on Baytril for any infection, and was also given Itrafungol in case of Aspergillosis. He seemed to pick up a bit, but on day 16 his condition worsened. The antibiotics were changed to Synulox and he was put on Critical Care Formula. By this time I had contacted the Southern Ground Hornbill Project in South Africa, (now the Mabula Ground Hornbill Conservation Project) who have hand-reared chicks for several years, and was emailed some day-by-day diet sheets. Unfortunately, I had got it all wrong. The chicks should have been on Lectade, the fluffs should have been skinned and gutted, and no mealworms or chick wings should have been given at such an early age. A lot of hand-reared chicks die of impaction before the age of 25 days. Parent birds have been seen regurgitating a fluid of some kind (possible digestive juices) that is thought to prevent this in parent-reared chicks. Other hand reared chicks die of infection, or just fail to thrive.
Unfortunately, I learnt all this too late for Bertie. After several more ups and downs, he died on the 11th May, on day 24. The post-mortem revealed septicaemia, cause unknown. It did reveal, however, that ‘Bertie’, had indeed, been a girl.
To have come so far and still lose her was upsetting for everyone involved. I doubted my ability to hand-rear these chicks, and decided that if she lay again next year, I would think long and hard before doing it again.
However, I didn’t even get a year to think about it. Two days after Bertie died, Jemima didn’t come out for breakfast again. So that day, 13th May 2006, I cautiously climbed up to her nest, half of me hoping she had laid, and half of me hoping that she hadn’t. I peered into her box, and there it was – an egg. She had double-clutched! Again, it was decided to remove it and incubate it, and on the 17th May, the 2nd egg was also removed. Dummy eggs were left, but once again, she buried them.
So – back to the waiting game. In due time, both eggs were found to be fertile, and although I was pleased, I was also very nervous. I had been encouraged by my colleagues to try again, and the thought of trying to rear two was pretty daunting. But at least this time I had gained a lot more knowledge from the Mabula Ground Hornbill Project. They were very supportive, and answered a lot of questions for me. I was as ready as I would ever be.
On the 19th June 2006, Slinky made his way into the world weighing 71g, followed on the 23rd June by Mischief, weighing 57g.
This time I took absolutely no chances. I followed the Diet Sheets religiously, sterilized everything I used, checked and re-checked the temperature in the hatchers where they were kept (34 degrees) and generally fussed and worried.
They were given ‘nests’ to sleep in, which was no more than a bowl with Vetbed material for comfort. These bowls increased in size as the chicks did. They were kept in a room where they could be kept quiet and in relative darkness. They don’t thrive well with lots of noise and disturbance.
Things progressed very well, the only concern being Slinkys’ right leg, which tended to splay out to the side. It was felt that it would be best to be left alone to see whether it straightened, and generally play it by ear. I had been aware of birds’ legs splaying out and even dislocating if the nest is too big or their legs slip and slide about. However, I believe Slinky had hatched like this, and time would tell if any intervention would be needed. Mischief had no problems at all and continued to thrive.
To say it was exhausting rearing these babies is an understatement. I was constantly skinning and gutting food, weighing, cleaning, and clock-watching for the next feed!! Because they hatch 3-5 days apart, the feeding regime differed for each of them in the beginning, with one being on 2 hourly feeds and the other on 3 hourly feeds. Then 3 and 4 hourly feeds – it doesn’t settle until they are both on 5 hourly feeds at about 3 weeks after the second egg hatches. I took them home with me at night, back to work in the mornings, and looked after them on my days off. And they don’t travel lightly!!
From about 3 weeks of age, they were put outside on warm days to get them used to different sounds and sights. ‘Nests’ were increased in size and temperatures were reduced slowly.
Mischief and Slinky out in the sun
From around 40 days, the birds started to try and feed themselves, so a bowl of food was left with them half an hour before each feed to encourage this. 10 days or so after this, they started to attempt to stand up. This takes a seemingly huge effort, with the wings being used for balance!! Slinky was slower than Mischief at achieving this because of his leg, but he did indeed get there in the end. Feathers were taken at this time for DNA testing to establish their sexes. Slinky is male, and Mischief is female.
Because of the natural group dynamics of alpha male/female and usually male helpers, it was decided to attempt to re-introduce Slinky to the parents in the hope of recreating the necessary structure for future parent-rearing. This was done from about two and a half months. A separate ‘introduction’ pen was built and placed in the adults enclosure. It was constructed from weld-mesh and allowed the adults to see him, but not attack him. He was left in this daily until just before he was due to fledge and then (under close supervision), was put straight into the adults enclosure. It was a very tense time!!
Well, Jeremy didn’t pay the slightest interest. Jemima, however, merely tried to feed him. She found some food and offered it to him. He didn’t accept. So she flew off and found something different for him to eat, offered it, and still he didn’t accept. She did this every day I left him with her, but I never did discover whether he accepted some food. I think with time, he would have done, but he was used to feeding himself at this point.
Unfortunately, the adult enclosure is on a fairly steep slope, and Slinky just couldn’t cope with it because of his leg. He was removed and put with Mischief in a separate outdoor enclosure (within hearing distance of the adults), which had plenty of room for them to practice flying and roosting etc. At this time, an x-ray of Slinkys leg was taken.
During all this, back at the beginning of July when Slinky and Mischief were only a couple of weeks old, Jemima didn’t come out for breakfast – again! She had laid her THIRD clutch of the year. We duly incubated and candled the eggs, and on the 6th and 11th August, Beeny and Spangle arrived.
I don’t think anybody had expected 3 clutches in one year, with a total of 5 fertile eggs. And I certainly hadn’t expected to be rearing 4 chicks in one go! Beeny weighed in at 75g and Spangle at 61g. I reared them in exactly the same way as before. At day 10, Spangles head started to bend right onto his back at feeding time, and this progressively got worse until he would actually topple himself over. Several people were emailed, and vets paid their visits, and it was decided that there was nothing neurologically wrong, and to wait and see what happened. I admit that I wasn’t convinced that he would survive, as it was difficult to feed him, and if he stayed like that there was no way he would ever be able to feed himself. I thought the likelihood of having him put to sleep was very strong.
However, never underestimate time. On day 21, I went in to feed him as normal, and there he was, sitting correctly, like nothing unusual had ever happened! Overnight, the problem had sorted itself out. He has been fine ever since. Beeny also developed well, except for a time between 35 and 45 days, when his appetite decreased. He was put on Synulox and Itrafungol and bloods were taken for testing. Nothing untoward appeared to be the problem, and again it just sorted itself out with time.
At the start of October, the DNA tests came through for Beeny and Spangle – both are female. So of the 5 eggs that hatched, only one was male. Also at this time, after x-rays being sent to Great Western Referrals in Swindon, it was becoming hopeful that surgery on Slinky’s right leg was a possibility.
On the 26th October 2006, Beeny and Spangle were put out with Mischief and Slinky in the outdoor enclosure. They had previously been ‘introduced’ for short periods of time, but this was the first time they would stay out permanently. They all mixed very well, and this is where they remain until other placements are found for the females.
On the 2nd November, Slinky was taken to Great Western Referrals for surgery. Further x-rays and ultrasound scans were done, and it was found that the ligaments around the stifle and knee were stretched, causing the leg to rotate outwards. The x-ray also showed a slight curvature of Slinky’s spine, which may have led to abnormal pressure being put on the right side. The cause was thought to be some kind of trauma somewhere between 2-3 ½ weeks of age, and not linked to husbandry or nutritional problems.
Surgery was performed to try and correct the ligament damage, and was initially a success. However, on the 24th November, I found him standing on his good leg, with obvious pain in the other. After consulting the vets at Swindon, it became apparent that there was absolutely nothing else that could be done. On the 25th November, Slinky was put to sleep..
After so much work from myself, other keepers, and Slinky himself, this news was very upsetting. But as Ann Turner from the Mabula Ground Hornbill Conservation Project said – ‘it is not easy , and thus successes are more rewarding’. How true.
Final Thoughts
Imprinting Some species of hand-reared birds don’t go on to be good parents themselves. So far, this doesn’t seem to be the case with Southern Ground Hornbills. There are two pairs at Umgeni River Bird Park in South Africa who were hand-reared without the use of puppets, and have gone on to double-clutch this year and last year, and also a female at Loskop who is in her third breeding year and reared her first chick. As social birds, they definitely prefer the company of their own kind, and although they habituate to humans, it seems that if they are raised with other chicks, they present few problems with breeding. Indeed, one particular chick was raised in isolation from other birds for a full year due to medical needs. This same bird then went on to integrate well into a group, although he is not old enough to breed as yet.
Breeding success
Most zoos/collections keep their Southern Ground Hornbills as a single pair. Indeed, this is how our pair at Cricket St Thomas were kept, and they bred very well. However, as co-operative birds, it may be a more natural situation if the breeding pair had one or two males in the enclosure to help with future rearing. So, would this stimulate non-breeding pairs to finally breed? We don’t know. Is it worth trying? Absolutely. And there lies the problem. With so few pairs breeding in captivity, there are few surplus males available. And to get surplus males, we need more captive breeding. It’s Catch 22, with no real solution.
However, there may be another way to increase captive breeding. In South Africa and in Europe non-breeding females are being removed and re-paired with different males. The males are territorial, so they remain in their enclosures and on the whole, it is the females who are moved. It is believed that females are fairly fussy and like to choose their mate, and there has been some degree of success with this method. A couple of non-breeding females in South Africa went on to lay fertile eggs within weeks of being with new males. However, the pros and cons need to be weighed up carefully. Capturing and moving birds can be stressful for them, and that alone may deter them from breeding for a while, whatever male they are with. Also, some ‘non-breeding’ pairs have been known to be together for 15 years before they eventually bred. So any program that may be developed to undertake this method would need to be carefully monitored, and done very slowly.
In South Africa, the wild birds will not generally breed until the rains come. They like hot and humid weather. Some birds in the UK (including our adults) start breeding in March, which ties in with the wet weather, but not the heat. So for birds that haven’t started breeding early in the year, it may be that adding a sprinkler to the enclosure as the weather heats up and the rain stops, may also kick-start breeding.
Do we really need to breed?? Absolutely! With less than 1500 birds left in the wild, the South African Ground Hornbill will soon become endangered. Although they have a naturally long life span, with only approximately one chick being raised to adulthood every 9 years the numbers will undoubtedly decrease. Add to that the shooting of them, and decrease in good nesting sites due to fires and old trees just dying, and the numbers speak for themselves. Also, they live in fairly limited habitats in few areas, and if disease were to strike, it would take out a massive proportion of birds.
So captive breeding is definitely needed. There is genetic testing being done at present to see if birds from different areas are indeed all the same species. Once this is established, then harvesting 2nd eggs and puppet-rearing the chicks for wild release becomes a real possibility . In South Africa, such chicks are released to adult groups at fledging, which serves two purposes – it ‘anchors’ the adults to the area for a while to enable people to study the group, and it also allows the chick to learn what it needs to survive. The young are monitored carefully, and the signs are encouraging.
For more information and diet sheets contact peapod777@hotmail.com or Jane Finch at Cricket St Thomas Wildlife Park.
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