# Keeping the dodos out of the field

About 100 people settled in a tropical area near a seashore five years ago. They've been feeding themselves by hunting and fishing, but now they're also trying to grow crops, including hemp and corn. They have adequate fresh water and late 18C technology. The neighboring indigenous nation is OK with them using as much land as they need and taking as much wood out of the forest as they require.

Their problem is the local flightless birds. Think dodos. About knee-high, the birds eat everything and they're aggressive.

• What options do the settlers have for keeping the dodos out of the corn?

My original thought was "build a big fence/palisade; plant inside the palisade," but I think they'd need a bigger planting area than they can fence. And the mean nasty dodos might chew through the fence.

• What options do they have for protecting their food if they succeed in growing it?
• And by "everything" I don't suppose we can feed them rocks until they're full before harvest season? Don't tell the RSPCA that I suggested feeding rocks to animals... – Dubukay May 18 at 7:30
• I would suggest to kill all the dodos, but I somehow guess that's not the desired answer... – kikirex May 18 at 12:37
• Why are the birds still around in the first place? They sound like a really good source of food and considering how the Polynesian expansion into the Pacific wiped out most of the regions big birds they should be gone by the time your settlers arrive. – TheDyingOfLight May 18 at 14:11
• Explain how this differs from e.g. deer eating your crops. Except that I bet deer can jump a LOT higher than your flightless birds. – jamesqf May 18 at 18:28
• The bigger the field, the shorter the fence is relative to the area. So there's no such thing as a field too big too fence. – Klaus Æ. Mogensen May 20 at 7:44

Dodos as you describe looks more like asset than a problem, better than big sack of grains. Plant large number of traps in crops for dodos, use crops as baits. Most dodo attacks would be at ripping season, you would gather more meat than required, so you will need to consider some meat preservation tech. as your climate is tropical.

• And before long we can consign the Dodo Mk II to the annals of extinction as well! Mmmm.. Delicious Dodo Jerky... – Joe Bloggs May 18 at 11:40
• @JoeBloggs 100 settlers are humans, so that's inevitable, (unless they are indians from bishnoi community ) – Rupesh Patel May 18 at 12:02
• But raising animals for food is highly inefficient. They’d also destroy the crops before they are even grown. Of course you could hunt/bait the dodos to extinction and then start planting crops … – Michael May 19 at 9:47
• @Michael they are not being raised for food. The dodos are being hunted, but they gather their own food from wild sources elsewhere in the woodland as well as the corn. The protein they provide is a bonus to the cultivated crops. – Sarriesfan May 19 at 19:58
• Of course, if they can gnaw through fences, they're going to be gnarly to take down! Mean birds! – Cort Ammon May 19 at 21:53

1. Guard dog.

You could train a dog to patrol the fields and chase out the dodos. That is dog work. If a cat shows up too that will be fine.

2. Copy the indigenes.

You mention a nearby indigenous nation. Pay them a visit. They live with dodos too. How are they doing it?

• Ya know, I wondered why the native people were "fine" with letting outsiders come in and take as much land as they wanted. Now we know...they've been herding all the dodos to the settlers' fields. Great strategy! – Cyn says make Monica whole May 18 at 15:30
• <g> They could do that... I thought the settlers attracted the dodos because they left garbage out, but that's even more fun. – SarahWriter May 19 at 15:10
• Seems like the easiest and more realistic option. The dog will not eat your crops and already has instincts suited to hunting other animals and chasing things off its territory. – Daron May 20 at 10:30
• Dog also leaves its scent all over the place which might already dissuade other animals from entering. – Daron May 20 at 10:30
• 2. Copy the indigenes. — If indigenes are hunters-gatherers they would simply lack this problem. Dodos can't ruin your crops if you haven't planted any. But dodos are good hunting game. – user28434 May 20 at 12:10

First of all, most birds don't chew. They beak, dig and stomp. But don't chew. Rodents are nasty chewing beasts, but not birds. Parrots seems to be chewing (credits @Starfish Prime for pointing this out).

• reinforced fences (dig well underground to install them) as passive mean.
• competitors as active mean: rats, pigs, foxes, dogs. We have heard plenty of stories on the damages they have done to island fauna when they were imported by the European explorers in the Pacific. Even egg eating snakes might serve your goal.
• bbq: don't tell me you want to eat corn all day, life long? If those pesky dodo are good to eat, let's have some bbq now and then. Dodo wings and grilled corn. Yummy!

If you do the above, I am sure that pretty soon your concern will be "let's save dodo from extinction".

Oh, since they don't fly, just store your harvest in a high place out of reach of their beaks.

• I'd say rodents are more about gnawing than chewing. Certainly, "beaking" is not used to mean "destructively crushing and tearing something into small pieces" in the way that chewing might be. Anyway, your semantic preferences aside, parrots are known to chew things up and I suspect that other bird species probably do so too. parrots.org/ask-an-expert/wood-chewing – Starfish Prime May 18 at 9:29
• @StarfishPrime, my frequentation with Shakespeare's language has not yet indulged into the semantic differences you point out, so it might very well be that I picked not the most appropriate terms. – L.Dutch - Reinstate Monica May 18 at 9:42

# Build that fence!

Most estimates state that a family of 4 needs 2 acres of land to be self-sufficient. That's the upper limit I've seen (with a couple exceptions). It's a lot more efficient when you have 25 families of 4 working together, you can grow year round in the tropics, and they have food from the ocean as well.

Assume at most the settlers require 50 acres for fields. This is very high and it's more likely to be closer to 25 acres.

A 50 acre circle has a circumference of 1600 meters, or one mile.

A 25 acre circle has a circumference of 1130 meters, or .7 miles.

Wooden fence posts plus barbed wire would be the best choice for a fence to keep out dodos. Since there is a tropical forest and they're allowed "as much wood as they want" the posts are the easy part.

Barbed wire wasn't invented until the mid to late 19th century. But wire fencing was available earlier and people did add sharp pointy things to it to make it hard to pass through. It's unclear to me if your settlers have metalworking to produce wire (they presumably have basic metalworking) or enough raw materials.

Thorny bushes are the other option. It's probably what the people who already live there use. Put in the posts and use wattling and some wire to contain dead branches of thorny trees and bushes. Plant seedlings of the bushes so you won't have to replace the dead branches for more than a few years. Combined with some wire, this will be unstoppable.

A mile of fencing is very easy for a village of 100 people to maintain. It's also fairly easy to build, once you have the materials. One full day's work for 1/3 of the village. Cutting the trees and making the posts is not time consuming. The metalwork is the bigger deal.

If you use barbed wire fencing, here's an estimate for materials to do 1/4 mile. Multiple by 3 for your smaller field and by 4 for your larger one. These are for modern materials and your settlers can get away with a lot less here.

4 8-inch wood posts
57 4-inch wood posts
55 6 1/2-foot steel posts
10 pounds staples & clips
6,600 feet 12-gauge barbed wire
39 hours labor

If you need to build a wooden fence, add wire! You can still use the wood for structural integrity but add the wire so the dodos don't peck through it. Or use other metal. Old rusted pieces of metal work great. Anything the community might otherwise discard.

On the outer side of the fence, whatever you build, add shells. You'll already be eating a lot from the ocean and you will have shells. Break them up so they're sharp and unfriendly to unshod dodo feet. Start with a thin line around the outside of the fence. Every time you have a pile of crushed shells to fill some buckets, send the kids out to add to the line.

Make sure you have a couple of very well-built gates and you're all set.

# Store your harvest on elevated platforms.

Build wooden platforms high enough so the dodos can't jump up or reach with their beaks. This should still be low enough for village adults to reach with ease.

If you have it, bamboo would be a great material here.

Add wire, shells, rusty metal, etc to keep the dodos from just pecking through the platform legs.

Bonus, this will reduce (not eliminate) rot from damp ground and insect infestation.

(This is a child's play structure but it's about the right size and shape. Store the ladder separately, if needed.)

• Cyn, this is beautiful! I never thought of thorny bushes. Now I just have to find something that grows mightily in Brazil... – SarahWriter May 19 at 15:00
• @SarahWriter Try these areas (different ecosystems close together): en.wikipedia.org/wiki/Caatinga and en.wikipedia.org/wiki/Agreste - And see: voyagesphotosmanu.com/brazilian_plants.html "Most areas of agreste are located near the São Francisco River and on elevated slopes, where some remaining moisture in the air is wrung from the trade winds. Thorny trees in those regions may attain heights of up to 30 feet (9 metres) and form barriers with their interlocking branches that even leather-clad vaqueiros (“cowboys”) cannot penetrate." – Cyn says make Monica whole May 19 at 15:27
• You can make wattle fencing and/or hedgerows from live plants as well, it works better and just gets harder to get though as it ages. you use dead stuff to fill in any gaps. It is pretty standard practice for farms. for storage look up something called a corb crib. – John May 20 at 13:43
• @John That is part of my answer though I might not have fleshed it out well enough. Thanks. – Cyn says make Monica whole May 20 at 13:43
• @SarahWriter someone on another question posted this link. Very relevant to you. atlasobscura.com/articles/colonial-india-british-hedge-salt-tax – Cyn says make Monica whole May 20 at 14:52

Plan A: BBQ Sauce

Eat them. Eat their eggs. Eat their chicks. Eat enough of them and they'll go extinct. The one thing humans are very good at is making other species go extinct. Flightless birds are absolutely no real threat to armed human hunters. If we can push Siberian tigers to the extinction point without trying, a giant chicken is a tasty deep fried treat.

Plan B: Pests

Rats basically wiped out the dodo. They eat the eggs and young while the parents are distracted. They breed quickly and are quite intelligent. Chances are the settlers brought rats with them and the rats have already started.

• … now you have to fight rats… – Jan Ivan May 20 at 7:39

Starting in 1932, Western Australia went through what is today known as The Great Emu War

The story could be summarised as follow:

• ex british and australian soldiers are given land in Western Australia after fighting during the WWI
• they make the land more inviting by clearing it and making water supply available
• a band of ~20 000 emus (they are giant migrating flightless birds) passing by found that the cultivated lands were now a good habitat
• they began spoiling and eating the crops and left holes in the fences, where rabbit and other pests could now enter
• the Australian minister of defence met with a delegation of ex-soldiers (now farmers), who required machine-guns to deal with the issue. He agreed with that and deployed two machine-guns handled by military personnel.
• two attempts were made at killing the birds, none of them was successful and the governement refused to send the army back when the farmers asked for it in 1934, 1943, and 1948

On the other hand, two things were effective against the emus:

• a bounty system (~57 000 bounties were claimed during a six month period in 1934, while the army killed at best 4000 emus while being on the field during two full months)
• farmers began using Pest-exclusion fences to guard the crops against emus (these are specifically designed to guard against a type of pest and used against emus in Autralia since the 1860's so I don't know if they're an option with late 18C tech)
• +1 for the Emu War call out. Though the insanity of it needs to be stressed. Australia declared War on it's National Bird... AND LOST (thank God for lacking Land Boarders). Having grown up near an Emu farm, I can say for certain fact, that these creatures were not burdened with an overabundance of intelligence. – hszmv May 20 at 15:06

Assuming the settlers don't have access to unlimited fencing material since if they could take a boat over to Home Depot or another local hardware store, then they wouldn't need to grow their own food since they have money and a supply chain.

They might dig trenches around their fields and pile the dirt up to make a wall. That way a 2-foot trench becomes a 4-foot high obstacle.

And if the dodoes are aggressive enough, maybe they eat their own dead or wounded. So hunting them, or standing guard with bows and slings might provide a diversionary food source.

Then there is the question of is corn their preferred food. If there is something they like better, humans could cultivate that too, along with corn, but in less quantity. Then the settlers could kill the Dodoes that made it through the barriers and toss their corpses over the barrier, either a warning to next ten generations of Dodoes or as food to satiate the hunger of the flightless fowl.

Are the dodos so aggressive that they aren't scared by people? If not than a scare crow would work or scare dodo in this case.

I would arrange settlements in a ring around the crops. 100 people is enough for some guard duty. Eating the dodos or giving the meat to the natives may go a long way to keeping relations healthy.