The three most invasive rat species, black or ship rat (Rattus rattus), brown or Norway rat, (R. norvegicu) and Pacific rat, (R. exulans) have been incrementally introduced to the Seychelles islands as humans have explored the world’s oceans. They have caused, and are still causing, serious deleterious effects through predation and competition. Eradication of these rats have been a challenge for years and one of the many ways in which the attempt to eradication was conducted up until late 1900’s was to encourage the Seychellois to use traps and offering a bounty on the rat tails. A very popular rat trap, or ratyer, was the bamboo bow rat trap or lasonmwar bambou, also known as Kob. In this post we will look deeper into this type of trap and also how the rat tail bounty was implemented.
Old Man with Bamboo Bow Rat Trap- lasonmwar
A brief history of rats in Seychelles
In the Indian Ocean, the invasion of ship rats appears to have begun at least as early as the ninth century. This was aided by traders from the Arabian Peninsula, with definite records of ship rats in eastern Madagascar and the Comoros by this time, with likely invasions of the Seychelles islands during this period.
By 1773 there were ship rats on Mahé, and by 1787 they were reportedly widespread on nearly all the islands of the archipelago (Malavois, in Fauvel 1909). Although a few of the smaller islands (e.g. Cousin, Cousine, Aride) have always remained rat free (Cheke 1984), as was Bird Island until 1967 (Racey & Nicoll 1984), and Frégate Island until 1995 (Thorsen 2000).
Norway rats did not reach the islands until very recently. None were found during trapping on Mahé and Praslin in 1976-7 (Racey & Nicoll 1984), and although they probably arrived in the late 1970s (Gérard Rocamora in litt.) or the 1980s (Hill et al. 2003), they were not reported until 1994 when they were well established on Mahé (Meyer, cited in Hill et al. 2003). They are now present on Mahé (and offshore Anonyme) and Praslin, having invaded and been eliminated on Conception and Frégate (Thorsen 2000, Hill et al. 2003, Gerlach 2007, Rocamora et al. in prep.). Ship rats may never have been present on Conception Island (Rocamora in litt.), hence the abundant survival there of the endemic bird, the Seychelles white eye (Zosterops modesta), which is a rare warbler-like perching bird from the family of white eyes (Zosteropidae). At one time thought to be extinct, it was rediscovered and is now listed as Vulnerable by the IUCN.
Seychelles White Eye
Ile aux Rats
Interestingly, we have one small island named after rats. This is’ Ile aux Rats’ which is about 700m from the island of Anonyme. Could it be that it got its name because it was infested with rats?
Rat Tail Bounty
Ship rats, adept climbers, attack birds’ nests and any reptiles in a size range too large to hide and too small to eat the rat; Norway rats are ground predators on birds’ nests and reptiles, and both species are important seed predators.
It was because of the distructive nature of rats as well as its potential as a disease carrier that, in the 1940’s, the Government introduced a bounty on rat tails.
At the start, a bounty of 2 cents was offered for each dried rat tail handed in. In 1947, the bounty was raised to 5 cents, resulting in more than 350,000 rat tails handed in between 1947 and 1949. The bounty was increased to 10 cents in 1963, in which year 152,776 rat tails were handed in (compared with an annual average of 46,000 for the previous four years).
Tail Tally
On 20th August of 1967, a “Tail Tally” was held at Gordon Square (Freedom Square) where a total of 25,590 rat tails were collected and $368 was paid in premiums.
Bounty Increased
Even though the coconut industry went into decline as tourism increased during the 1970s, rats were still very numerous and in the 1980s the bounty increased to 1 Rupee, after which people became more wary of handling rats due to the fear of the rat-transmitted disease, leptospirosis, which can be lethal to humans.
Controlling rats with Barn Owl
The barn owl (Tyto alba) was introduced in Seychelles from East Africa in 1949 for the control of rats in coconut plantations. The department of Agriculture introduced three barn owls first to Ile Platte on the 27th April 1949. Later on, 15 were introduced to Union Vale on the 31st December 1951. (Annual Agriculture Report 1949, 51) 6 were introduced at Le Niole on July 29th 1952 and August 9th the same year. Barn Owls were found to be on all granitic islands of Seychelles in 1974 including Cousin & Cousine.
The Barn Owl
The introduction of Barn Owls in Seychelles was an unsuccessful attempt to control rats. Records show that instead of eating rats the barn owl turned on the local birds, particularly the white fairy tern (Gygis alba) and caused great damage. Due to an increased awareness of the conservation of biodiversity in the late 1960s, a reversal in policy in 1969 resulted in a Sr. 5 bounty being offered per head of dead owl, with some 40 owls brought in during the first 2 years.
How do you make the Bamboo Bow rat trap?
This activity consists of four tasks, ie. the making of the traps, the baiting and setting of the traps, the collection and the drying of the tails and the selling of the tails.
Prepare the Bamboo
There are different types of bamboo that are grown in Seychelles. We have banbou dsin, banbou nen, banbou ver and banbou zon and banbou leren. The best banboo for the traps is banbou ver because is quite narrow and camouflages well in the green grass.
Source medium size bamboo, with an inner diameter of about 7cm, with a good distance between the nodes, at least 40 cm apart.
Cut the bamboo into more or less equal lengths, about 5 cm from the node, in such a way that there is always and open end and a closed end. The open end becomes the entrance or mouth of the trap. The node at the back-end acts like a natural wall and stops the rat from entering from behind.
Pierce the holes for the Spring Stick
Once all the bamboo has been cut, trim all the edges properly to remove any sharp edges that can easily cut your hand.
A Bamboo Bow Rat Trap-Lasonmwar
Pierce a few holes in the cut bamboo. To pierce the holes, you can use either a very hot metal rod or a hand drill or an electric drill. Pierce two fairly large holes close to the node at the back end of the bamboo from top to bottom with the top one being slightly larger than the bottom one. It is through these holes that the spring stick will be inserted. The spring stick can be made of either a flat piece of bamboo itself or, better still, a small branch or twig of bwison (Ixora finaysoniana) because it can bend without breaking and has good spring effect. Sometimes bwadir (Canthium bibracteatum) was also used.
The difference in the hole size is to accommodate the natural tapering of the spring stick. I forgot to mention that you have to source the spring stick before you pierce the holes because the thickness of the spring stick dictates the size of the hole to be drilled.
Drill the holes for the noose and trigger
Once you have accessed your spring stick and drilled the hole, you will need to drill five holes at the front end of the bamboo. Drill two holes side by side on each side of the bamboo mouth, about 4cm from the opening, resulting in four holes altogether. The outer ones being slighter larger (approx. 1cm wide) than the two inner ones (½ cm wide). Then drill the last hole, approximaletely 1cm wide, directly in the middle of the four front holes about 10 cm from them. Clean all the holes to ensure that there are no sharp edges.
Once the bamboo is ready, start to prepare the other parts. Smoothen the spring stick, removing any small twigs and cut it to the correct length, approximately 100cm. Sharpen the bottom end and place a small notch at the top end.
Make the toggle.
The toggle is a small piece of wood, thinly trimmed that is tied horizontally to the line forming the bow. Its purpose is to activate the trigger. It is slightly flat about 10cm long and 1cm wide and ½ cm thick. Create a little notch at one end approximately 1cm from the end.
Photo Showing The Toggle, Trigger and Position of the Holes
Make the trigger.
The trigger is usually a metal pin like an elongated nail with a pointed end and a flat end. It can be made with thin metal wire that will not bend under pressure or with a small piece of hard wood. The length should be the total length of the perimeter of the inner part of the bamboo and the height of the loop. It is inserted in the single large hole at the front end of the bamboo with the sharp end in the bamboo and the flat end on the outside. The trigger will have its sharp end inserted in the bait and the toggle will sit on the other end.
Assemble the parts of the Bamboo Bow Rat Trap
Now that you have all the parts you need to assemble them to make the trap.
Make the small loop that will hold the toggle. Access some string or fine rope and cut a piece of about 30cm. Insert one end through one of the two inner holes and out through the other and tie the ends together . This loop is now done and the knot has to be very tight as the loop holds the toggle and it has a lot of pressure on it. The two outer ones, are for the noose.
Insert the spring stick through the holes in the back end of the bamboo. Unsure that you insert the tapered end first through the holes until tightly secured. You need to leave about a good 15 cm sticking out underneath the bamboo. This is inserted into the ground to act like an earth anchour when the trap is set so that it does not fall over.
Access another piece of string, similar to that used for the loop and cut a length of about 80 cm. Tie one end to the top end of the spring stick and apply some pressure and insert the other end of the string through the one of the larger holes and out through the other hole and tie a big knot at the end of the string so that it does not get pulled back when you let go of the spring stick. You now have what looks like a half bow.
Press down again on the spring stick and tie the toggle to the string. To get the right spot to tie the toggle you need to measure the inner perimeter of the bamboo and add the height of the loop.
Baiting the Trap
Mouth of The Bamboo Bow Rat Trap Showing the Bait and Noose
Now that we have assembled the trap, we are ready to bait it. The bait that was commonly used was grilled coconut. The grilled coconut seemed to attract the rats better than plain coconut. Crack open a coconut and with a blunt knife pry small pieces of coconut from the shell. When you have had enough, throw them for a few minutes into a fire, remove and allow to cool. Place a piece of the coconut in the trap directly underneath the trigger and force the sharp end into the coconut.
The Ideal Bait- Code de Mer Kernel
We were not allowed to use fresh coconut for the bait because of the value of coconut at that time. We therefore had to be creative and source another alternative. That other alternative was even better than coconut and lasted for months. We would source the dried kernel of the coco de mer. It was not easy to obtain, but we had all the contacts and in fact we also had some coco de mer trees growing on our property. The dried kernel is as tough as a brick. We had to use a hand saw to cut it into appropriate pieces, and then use a hand drill to drill the hole for the trigger. However, one major advantage was that as bait it was never used up as the rats could not get their teeth into it. We used to wash it once in a while and regrill it every few months.
Setting of the trap
Armed Bamboo Bow Rat Trap
Once you have chosen the spot to set the trap, apply some pressure on the bow to slacken the string. Then hold the toggle, pass one end through the loop and rest it on the trigger. The trap is now armed. Turn the mouth of the trap towards you and form the noose in the bamboo with the loose string that resulted in moving the trigger stick down. The noose is done by lining the inside of the bamboo with the string.
Place the trap down and force the ground anchor into the ground. The trap will now stand straight with no obstruction to the spring stick. When the rat enters the trap and bite on the bait, it will invariably move the trigger stick and release the toggle and the spring stick will pull back catching the rat by the throat.
I would set my trap inside the sugar cane plantation that we had. The rats were attracted to the plantation by the sweeteness of the cane.
The double-mouth trap- Lasonmwar doub
The correct size bamboo was at times hard to find, so we had to maximise the bamboo we could get by making a double-mouthtrap, locally known as Lasonmwar doub. The Lasonmwar doub is a bamboo trap that has two openings one at each end of the trap.
Double-Mouth Trap – Lasonmwar Doub
The bamboo was cut in such a way that the node was located in the middle of the trap and the trap was more or less duplicated. All the parts are the same as the single trap as well as the assembly of the parts.
My personal venture in the ‘rat tail business’.
When I got to the age of 15, I decided that I needed to get some pocket money and it was then that I started to get involved in making my own rat traps and capitalise on the bounty. I was young then and had no idea of the high level of risk that was attached to this hobby. The possibility of exposing myself to all sorts of infections including the deadly leptospirosis was very real. And yet, I, as well as many other young kids at the time, survived and the rat tails became my main source of pocket money.
The collection and the drying of the tails
In the early hours of very morning, before going to school, I would rush into the sugarcane plantation and check on all the traps. The rats were removed from the traps and the tails cut on location. I would carry the severed tails to the house and place them on a rack ,called tartar, to be sun dried. The tartar was high enough to be out of reach of cats. The tails were airdried for over a week and packed in bundles of 25 and then placed in a large cake tin. They were very closely guarded.
Cut Rat Tails- Lake Lera
The selling of the tails.
When I had enough tails, I would take them to the agricultural department at Amitié, on Praslin Island, where they were counted by Monsieur Dubuisson who was the manager of the department then. It is hard to describe my excitement when suddenly I was rich!!
Rat Tail Bounty immortalized by Mickey Mancham
Mickey immortalised the Rat Tail Bounty in this song. ‘Laronde le Rat’ .
Sources
- Seychelles Nation
- The timing of arrival of humans and their commensal animals on Western Indian Ocean oceanic islands. Anthony Cheke
- Annual Agriculture Report 1949, 51)
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