History of Jersey Zoo & Durrell Trust ex-situ / in-situ conservation efforts.

The arrival of the Montserrat oriole at Jersey zoo (1999)

The final year of the decade also brought the arrival of another enigmatic and endangered Caribbean species to Jersey zoo, a beautiful little passerine called the Montserrat oriole.

As with the mountain chicken the Montserrat oriole was also severely threatened by volcanic activity on the island of Montserrat throughout the 1990's.

However, unlike the mountain chicken the oriole was endemic to Montserrat and did not occur on the neighbouring island of Dominica.

This effectively meant that this bird had nowhere else to go and without the timely intervention of conservation its extinction would be assured.


Photo credits to @gentle lemur and @AdrianW1963.

 

The rationale for and planning of the capture of the Montserrat oriole (1999)



Rationale of capture

By the late 1990's and in the aftermath of frequent volcanic eruptions on Montserrat it had become obvious that if nothing was to done to establish the Montserrat ex-situ it would potentially face extinction in the wild :

"The Montserrat oriole Icterus oberi is the island's only endemic bird whose primary habitat before 1995 was in the mountain forests and gullies (ghauts) in the south of the island."

"The small 39 km2 island of Montserrat in the Leeward Islands of the eastern Caribbean has experienced volcanic activity from the Soufrière Hills volcano since July 1995. The Irregular eruptions, heavy ash falls and pyro-clastic flows have caused severe damage to the island’s infrastructure and to much of its remaining forest."

This difficult decision had been made due to the unpredictability of future stochastic events through volcanic eruptions and how this might further impact the island's forest ecosystem and endemic bird:

"Despite the relatively high numbers of Icterus birds still remaining at the time and the reduced activity from the volcano, the Montserrat Alliance decided that because of the unpredictable nature of the island’s volcano, it would be prudent to collect from remaining forest a small number of orioles."

The Durrell Trust therefore organized an expedition to bring back a select number of orioles to Jersey Zoo to begin the first captive breeding programe for the species:

"An expedition to collect four pairs and establish them at Jersey Zoo, in order to carry out trials into the husbandry and captive breeding requirements of this avicultural unknown species, was therefore mounted."

The planning for the capture

The first important part of the plan was to construct holding aviaries for the captured birds:

"On arrival in Montserrat the first task, before any orioles could be trapped, was to find a suitable site for the establishment of temporary holding cages or aviaries for the birds."

Luckily a suitable location for doing this was soon found :

"Following the advice of ministry personnel, a site was chosen at the Ministry of Agriculture's plant nursery in St Peters. This location offered shade and seclusion for the birds, and was situated relatively close to areas of forest where trapping would take place."

With the site now chosen it was imperative to begin work on constructing the holding aviaries:

"The area therefore chosen to build the holding aviaries was a large wooden-framed structure, which was used for growing local forest plants. The decision was made to build eight individual aviaries within the existing structure, as it was not known whether the orioles would behave aggressively towards cage mates once in captivity."

Work therefore began as quickly as possible:

"The eight aviaries (3 m long x 1.5 m wide x 2.5 m high; Plate 5) were constructed using a timber framework with the walls and roof made from black shade cloth. Shade cloth was chosen as it gave the birds some protection from the intense sunshine and would reduce any interaction between birds in adjacent aviaries. Using this material, rather than wire mesh, also facilitated the quick con struction of the aviaries, and they were built within four days."

A few finishing touches to reduce the stress levels of the captured birds completed the job:

"Thick cover for the birds was provided using cut leafy branches. Plastic trays were attached to each aviary frame for food and water receptacles. The floor substrate was soil and leaf litter."





Photo credits to @Tomek and @vogelcommando.

Source: "The collection of eight Montserrat orioles Icterus oberi and their establishment at Jersey Zoo.", Andrew Owen, 2000 (Journal: The Dodo).

 

The capture of the orioles (1999)


The capture attempts

The capture method used for the Montserrat oriole was "mist netting", a technique that is commonly used for the live capture of both bats and small birds. The sites for the trapping on the island had to be chosen carefully:

"Mist netting attempts were carried out at various locations between 1 and 10 July 1999. Mist netting began early in the morning, when the temperature was cooler and the birds were most active. Each of the sites chosen by the forest rangers was a known oriole site or an area which appeared to be suitable oriole habitat. These were normally in an area with a number of stands of Heliconia caribaea plants, the favoured nest site for the species."

The nets had to be set up in different ways to increase the chances of capturing the birds:

"If located in an area of thick vegetation, a strip approximately 2-3 m wide, and the length of the nets, was cleared. Up to four nets were used, depending on the steepness of the ter rain. Three-shelf mist nets were used. Each net was 15 m in length and was attached to aluminium poles and supported by guy strings. The nets were set from ground level to 4 m high. Up to three lines of nets were set in one area to maximize the chances of catching orioles."

To attract / lure birds to the nets a tape recorder with recordings of territorial calls of the species was used:

"Once the nets were in place, all personnel sat quietly at one end of the net, and a tape recording of a calling male Montserrat oriole was then played at intervals in an attempt to attract any orioles defending territories in the vicinity into the nets. The forest rangers also imitated calling orioles by whistling."

"If after one or two hours there were no signs of orioles in the area, one of the rangers searched for a more suitable area. If a suitable site was located, the nets were closed and moved to the new area."

However, there were a number of difficulties and frustrations in the capture attempts :

"During the mist netting procedure a number of other bird species were inadvertently caught. These were freed from the nets, photographed and released"

"At most two orioles were caught on any one day. During 10 full days of mist netting in total (approximately nine hours per day), on three full days no orioles were caught."

However, eventually the desired amount and sex ratio of orioles were caught these were then banded, measured and weighed to gain data and then taken to the holding aviaries :

"Once caught, each oriole was ringed using coloured split plastic rings, and the skull, bill, tarsus, wing and tail measured using adjustable callipers. The bird was then placed inside a small cloth bag and weighed using a Pesola 300 g spring balance, accurate to 2 g."

The holding period


It was important initially to observe the captured birds to make sure that no agonistic behaviour occured:

"During the holding period on Montserrat the birds were kept as pairs (B4610 and B4615; B4611 and B4612; B4613 and B4614; B4617 and B4616), one in each of four of the eight aviaries that had been constructed. Close observations were made to ensure that no aggression occurred between pairs sharing each holding aviary; no aggressive behaviour was seen."

Every care was given during this period to avoid stressing the birds more than necessary and ensuring that the birds received the best possible nutrition:

"Fresh water for drinking and bathing was provided in a shallow dish and placed on a tray attached to the wooden frame of the aviary. Food was provided in a number of feeding receptacles, shallow ceramic saucers and plastic D-pots at various locations around the aviary, to ensure that the birds did not have any difficulty finding food and that individual birds would not dominate favoured feeding stations."

"Although little or no fruit is thought to be taken by wild Montserrat ori oles, it was provided for the captive birds in the form of finely diced pieces of apple, grape and banana added to the dishes of insectivorous food, and large slices of mango or papaya spiked on to branches. Insects which had been brought to Montserrat from Jersey were offered in the food dishes: small mealworms Tenebrio molitor, house crickets Acheta domesticus and wax-moth larvae Galleria mellonella."

"The birds were fed and watered early in the morning, usually at 0600 prior to further mist netting in the forest. They were checked at midday and again late in the afternoon, when they were given a second insect feed. During the midday inspection, the aviaries were given a thorough soaking using a hose pipe. This helped the cut branches in the aviaries retain their leaves and seemed to be appreciated by the birds, which actively bathed in the freshly replenished water dishes."

However, the orioles quite understandably remained highly strung and nervous around humans during this time:

"When the aviaries were approached or entered the orioles became nervous and flew from end to end, or attempted to hide in the vegetation. At other times when observed from a distance they remained calm, and were seen feeding, bathing or sitting quietly in the foliage."

The Journey back to Jersey


The need to transport the birds as quickly as possible back to the zoo was now imperative and preparations were made accordingly:

"Once all eight Montserrat orioles were caught and established in the holding aviaries, there was some urgency in transporting them to Jersey Zoo as soon as possible as food Sup plies, particularly insects, were running low. Following health clearance by the local veteri narian and completion of all permits and trans portation arrangements to Jersey, the birds were caught on 13 July 1999 and placed in two wooden carrying crates divided into four compartments per crate, each measuring 19 cm x 30 cm x 25 cm, with one bird per compartment. The birds were provided with food and water (offered in small plastic drinking tubes)."

"Once crated, the birds (and nine mountain chicken frogs Leptodactylus fallax also collected on this trip) were transported by road the short distance to Montserrat's Helipad. They were then flown 25 minutes to Antigua's ET Joshua International Airport. In Antigua the orioles and frogs were inspected and given clearance by the Ministry of Agriculture's chief veterinary officer."

The birds were put aboard the flight back to Jersey from the Caribbean and eventually arrived safely after a long journey:

"They were then placed in the cargo department's facility for 11 hours, awaiting the connecting flight to London. Here I was able to visit them regularly to ensure they were fit and well. From Antigua they were flown to London Gatwick Airport, then travelled by road to Heathrow Airport, finally arriving in Jersey on 14 July 1999 after spending over 30 hours boxed and in transit."



Photo credits to @gentle lemur, @gulogulogulo and @Tomek (Photos not taken at Jersey but at other European zoos).

Source: "The collection of eight Montserrat orioles Icterus oberi and their establishment at Jersey Zoo.", Andrew Owen, 2000 (Journal: The Dodo).

 

Housing of the orioles at jersey (1999)

After the arrival of the orioles at the zoo the first task was to put the birds into quarantine for a period of time in which they could be observed and the conditions of their health thoroughly assessed.

After the quarantine all eight orioles were then housed in their breeding pairs within four lushy planted avairies at the zoo which had been made ready for their arrival.
Here in these new surroundings it was hoped these still nervous animals would continue to acclimatize / settle and eventually breed and contribute to the nascent captive breeding programe.

The hopes for captive breeding would not be disappointed and almost immediately the oriole pairs began to show courtship behaviour and to breed.

A mere year later there had been six chicks that had been successfully reared by the birds without the intervention of handearing.

Soon the offspring would be sent to other zoos across the UK and Europe who were also part of the EEP for the oriole which was to be coordinated from Jersey zoo.


Photo credits to @JerseyLotte, @gentle lemur, @DesertRhino150 and @molinea (Photos of birds taken at Zoos other than Jersey).

Sources: - "EAZA Passeriformes TAG Annual Report 2000", David Jeggo, 2000.

 

First captive breeding of the mountain chicken (2000)

At the end of the decade and the turn of the new millenium a notable success and suprise would be the breeding of the mountain chickens that had been collected a year earlier during the summer of 1999.

Through the use of cameras the female frogs had been discovered to be making underground foam nests within their terrariums and feeding the tadpoles with unfertilized eggs.

This represented the first ever captive breeding of the mountain chicken and was therefore a very fitting and special Millenial achievement for the zoo.


Photo credits to @gentle lemur and @Javan Rhino.

 

Wrap up of the Montserrat oriole ex-situ situation today

The situation facing the Montserrat oriole in-situ today remains troubling and its continued future in the wild is far from a certainty.

However, thanks to the ex-situ captive breeding programe initiated by Jersey zoo in 1999 the prospects of the survival of this beautiful Caribbean bird are a little brighter.

Today the captive population of the Montserrat oriole (as of 2020) stands at 56 individual birds that are held at several zoos (16 institutions) spread across Europe.

This insurance population is incredibly valuable and continues to steadily grow with every passing year with the regular breeding and rearing of birds.

Jersey zoo continues to coordinate the ex-situ conservation of the oriole and monitor its precarious status in the wild.

Photo credits to @ThylacineAlive and @vogelcommando.

 

So with the Montserrat oriole this brings the history of Jersey zoo's notable ex-situ programes during the 1990's (and therefore the thread) to a close.

I might write a final conclusion about the decade as a finishing touch.

If anyone has any further comments to add to this thread it would be much appreciated.

 

Conclusion to history of Jersey Zoo / Durrell trust ex-situ conservation efforts (1990's)

In the more than half a century history of Jersey zoo the 1990's stands out as one of the defining and formative decades for the organization due to the notable successes that were achieved within such a relatively short period of time.

13 species on the brink of extinction arrived at the zoo having never been kept successfully in captivity before and each of which presented steep husbandry challenges from the outset.

However, thanks to the persistence and dedication of the staff the husbandry of these animals was eventually to be pioneered through rigorous research and mastered through trial and error.

The majority of these species were bred for the first time in captivity at the zoo and thus formed incredibly important insurance populations ex-situ and became ambassadors for their species.

Examples of such species include: the Livingstone's fruitbat, the Malagasy giant jumping rat, the lesser Antillean iguana, the flat backed tortoise, the aye-aye, the Lac Alaotra gentle lemur, the Madagascar teal and the mountain chicken (all of which remain at the zoo to this day).

Others were bred for the first time in captivity by a zoo outside of the range country. Examples of such species include the black lion tamarin, blue crowned laughing thrush and the Mauritius kestrel (the only species that sadly is no longer kept by the zoo).

Some of the species that arrived during this period continue to present steep challenges to their successful management in captivity such as the pied tamarin, mountain chicken, blue crowned laughing thrush and the flatbacked tortoise.

Yet the tireless work and research to ensure the survival of these species continues to advance quietly year after year.

It is ultimately thanks to Jersey zoo and their historic pioneering efforts throughout the 1990's that we are able to contemplate many of these weird and wonderful species that are now kept by a good many zoos.


Photo credits to @Giant Eland, @Indlovu, @Therabu, @ronnienl, @LSouthern, @gentle lemur @ThylacineAlive, @HOMIN96, @Joker1706.

 

This is a most interesting thread with an incredible amount of detail, highlighting the work on some of the most iconic species that Jersey Zoo works with. Establishing a species in captivity is not necessarily by itself conservation. It is only conservation when the work in captivity informs the work on the wild/free-living populations. For many of the species highlighted in this thread Durrell are working with the species in the wild and the captive work informs and drives this work. However to link the captive and wild work is far more difficult than many would believe. When species of conservation concern are brought into captivity important questions need to be asked.

• What are the major knowledge gaps with regard to life-history and behaviour that can be filled by studies on the captive animals? These data may then be used to help interpret data on population biology and what is limiting the population.
• What management techniques can we develop in captivity that can then be applied to managing the wild free-ranging populations to boost productivity and survival? For example, the effective use of nest-boxes and breeding sites, supplemental feeding, disease management, and predator/competitor control and exclusion.

The challenge remains, how do we more effectively use captive animals to enhance the conservation of the species in the wild?

 

Thank you for your kind words @Carl Jones ! Much appreciated !

I totally agree with regards to conservation and the work that the Durrell Trust have done ex-situ consolidating and informing the in-situ work of species conservation. Many of the species that arrived at Jersey zoo in the 1990's have very interesting and long-term in-situ stories of species and ecosystem conservation that are continuing today.

Some of these I knew about fairly well like the black lion tamarin in Morro do Diabo but there were quite a lot that I enjoyed reading and familiarising myself with during the writing of this thread like the Lac Alaotran gentle lemur at Lac Alaotra, the giant jumping rat in the Kirindy forest, the Livingstone's fruit bat in the Comorros and the Lesser Antillean iguana in Dominica.

Also agree with your point about the difficulty of linking ex-situ work within zoos with meaningful in-situ conservation towards species conservation. I think the great strength of Jersey zoo / Durrell Trust and what sets them apart from all other zoos is the way that these two components of conservation are treated for the most part holistically and with a commitment to the long-term.

I think that with regards to how captive animals might enhance conservation of the species in the wild there were some really interesting examples that occurred at Jersey in the 1990's which are particularly pertinent. I think that this is especially the case in terms of the Callitrichids and the free-ranging experiments that were implemented particularly with the black lion tamarin.

 

Ouch...that is definitely a downer.

I do feel hopeful that there will be future opportunities to see this beautiful little raptor as I believe that zoos may get back into keeping them (they never should have stopped in spite of the difficulties IMO).

I am actually in the same boat as I have never seen a Mauritius kestrel but it is amongst many other species that are deeply symbolic as conservation success stories like the pink pigeon, Lorde Howe Island stick insect and black footed ferret that I would dearly like to.

 

@Carl Jones I thought I'd ask you a question that I've been asking myself and wondering quite a lot during this thread.

The 1990's along with the 1970's and 80's seems to be a defining decade when a lot of species arrived at Jersey and a lot was historically achieved in both ex-situ and in-situ terms.

The 2000's and 2010's appear to have seen a shift towards a greater emphasis for in-situ work and ex-situ but within the range country of species.

What do you think the future may hold for Jersey zoo in terms of ex-situ conservation?

Do you think there will be decades like the 1990's at Jersey again ?

 

This is an interesting question, I hope that Durrell will be working more and more in the countries where the species come from. Breeding species in Western zoos to return them to their native countries is an Imperialistic approach we should be moving away from.

I here attach some thoughts from an article I wrote:-

"The typical zoo of the future will be geared towards the display of domesticated zoo animals providing opportunities for general education and fund-raising. Of course, just as we do now, typical zoos will be involved with conservation. The conservation focus will be upon learning and training, and the transference of skills and knowledge from captivity to the wild and vice-versa. Zoos have been most effective when working on the restoration of native species for example the work by some North American zoos in the restoration of the bison Bison bison, California condor Gymnogyps californianus and black-footed ferret Mustela nigripes, and the work of Durrell in restoring both the agile frog Rana dalmatina and red-billed chough Pyrrhocorax pyrrhocorax on Jersey. In addition zoos have been effective in restoring species when they establish captive breeding and restoration programmes in the range countries as Durrell has done in Assam, Madagascar and Mauritius. This trend will continue and specialist collections working on re-introduction, will be breeding species in their range countries. A major caveat being that increasingly, in a rapidly changing world, it is going to be necessary to introduce species into areas outside of their current ranges.

We will be using captive animals in zoos to learn more about them and to develop conservation management techniques. This knowledge and these methods can then be transferred to range countries. This is the vision of the Durrell Conservation Academy, and we seek to teach staff and students how to integrate the management of captive animals with those that can be used to restore wild populations.

More and more populations of rare and threatened, free-living species will be managed using captive management-type techniques. Management to boost productivity and survival will be readily applied to declining populations, by supplemental feeding, disease control, predator control, or the provision of predator free breeding sites. The boundaries between captivity and wild will be blurred and there will be a fluid exchange of ideas, techniques and animals between wild and captivity. Keeping free-living animals that are still dependent upon some forms of management is much superior to keeping them long-term in captivity since they will fulfilling their ecological roles and still under some natural selection.

Gerald Durrell was a pioneer in developing zoos as conservation organisations and was not shy about challenging orthodoxy. He established the Durrell Wildlife Conservation Trust as a zoo that would develop new approaches. It is incumbent upon us to continue his vision, question the status quo, and look for more effective ways of conserving endangered species."

 

Thank you for your reply @Carl Jones ! This is a very interesting topic indeed.

I generally agree that it is an approach that has historically been rooted in an imperialistic model of conservation and that zoos could work far more effectively in supporting in-situ efforts within range countries in terms of training / capacity building / exchange of knowledge and skills and logistics.

I do think though that there are cases where there may be some utility to holding species outside the range country and that Jersey zoo has managed to strike this balance remarkably well and serve as a model of this to other zoos.

However, I think that most zoos have given quite a bit of lip service to the idea but have noticeably failed to follow this model or to follow in Jersey's footsteps in this regard.

Again, fully agree with your statement on the need for zoos to focus on the conservation of native species and this is something in particular that I would dearly like to see adopted more widely within Latin America with native biodiversity.

Blurring of boundaries between wild and captivity is another trend that I see on the horizon too and particularly within protected areas where meta-populations of conservation dependent species are being managed and particularly in the case of Callitrichids.

The only thing that I find myself disagreeing about would be the display of domesticated zoo animals but admittedly this is probably because I am very biased against the ABC species trend in zoos and quite ideologically / emotionally invested in the "little brown jobs" and profiling them within zoos.

 

The process of domesticating zoo animals is well under-way and is unavoidable and zoos need o be embracing the domestication of their ABCs.

Here again I quote from an article I wrote:-

"In captive populations not all the animals will breed, and rates of productivity are such that some animals are prolific and others are not. Consequently there can be rapid genetic drift, loss of genetic variation, inbreeding, and selection for the characters that suit a life in captivity. Sub-specific characters may be lost. The selective pressures in captivity are very different to those in the wild. There are no predators and usually no inter-specific competitors. The captive environment is usually far less complex, is less stimulating and some captive environments are akin to deprivation chambers. For example, compare the environment in which most breeding captive parrots are kept –relatively bare wire cages with a few perches, a simple wooden nest box, and they are fed a pelleted diet – with the stimulation they would experience in the wild.

Within the first generation of being in captivity the nervous, highly strung individuals, that are selective about choosing their mates are less likely to breed compared to the more docile and unselective individuals. Even with rigorous adherence to genetic management and the maintenance of the founder representation, the docile, more tractable and promiscuous individuals are the ones that are more likely to prosper.

The effect of captivity and domestication has a profound effect upon behaviour and can produce animals that are less able to survive in the wild compared to their wild counterparts (Bryant and Reed 1999). Domestication causes a reduction in the size of the brain, thyroids, pituitary and adrenal glands (e.g. O’Regan and Kitchener 2005). How quickly these changes occur is likely to be species specific although all species are susceptible to becoming domesticated (Frankham et al. 2002) and there can be changes in less than ten generations (e.g. Lacy et al. 2013) – and perhaps even within a single generation (Christie et al. 2012). "

 

Yes, again, I agree with you that domestication of the ABC's in zoos is an unavoidable phenomenon (in my view unfortunate but inescapable).

Moreover, it is a process that we do need to be vigilant in guarding against happening at all costs with insurance populations of endangered species in ex-situ settings such as zoos.

This is why I agree with your stance on the blurring of boundaries between captivity and the wild in terms of in-situ and ex-situ conservation as this is another inevitability as protected areas shrink and contract under anthropogenic pressure. I see enormous utility in this form of management with regards to the conservation of the Callitrichids in the Atlantic rainforest here in Brazil in particular.

I also believe that this would help avoid the genetic domestication that occurs within zoo environments which renders reintroduction efforts to the wild at the most impossible and at the least incredibly costly and logistically challenging.

Somewhat related to this subject I also think that developments such as the improvements in the flying fox enclosures at Jersey zoo really illustrate how research into improving aspects such as enclosure design may deliver huge benefits down the road when it comes to priming species for reintroduction to the wild.

 

Saw this video on the EAZA youtube channel which features the Durrell trust's Dominic Wormell talking about some of the techniques that Jersey zoo pioneered with free ranging Callitrichids.

 

Extremely interesting thread, many amazing animals the world has Gerald Durrell to thank for his pioneering work!

Is there any information on Jersey working with Duke University with aye aye? Or any information on the aye aye held in Germany? I know that it's abit off topic as not directly collected by Durrell.

 

Thank you for your comment @Sausagefingers ! Much appreciated !

I'm glad you enjoyed reading through this , thanks for the kind words !

This thread was a bit of a mini project of mine and I enjoyed writing it as I went through lots of old papers and read about / got acquainted with the history of the ex-situ conservation of these species at Jersey and learned a lot in the process.

Regarding information about Jersey working with Duke university with the aye-aye, yes, I remember there being a bit of information about this collaboration so I'll try to find some of it later and post here on the thread for you.

Don't remember about aye aye in Germany but I do remember there being mention of the aye aye kept at the Paris zoo.