2018-03-15

Costa Rica - Wildlife Refuge Laguna Urpiano

Time flies. It's been a year already. I am thoroughly enjoying my job at Oak Ridge National Lab.

I got used to much of the U.S. American weirdness and other differences to home. Deep-fried sushi, deep-fried pickles, shitty bread, disgusting tap water, cars everywhere, lots of driving and so on.

July last year, three friends and I spent two weeks in Costa Rica volunteering at the sea turtle refuge Laguna Urpiano - a breathtaking experience. I'm not sure where to start. The refuge is located on the eastern side of the country without any direct access except through a canal. There is no sewage, no tap water, no electricity. The refuge has a well, runs a generator to pump water, and some solar cells that charge batteries for lighting at night, and smart phones.

On the way to the refuge

The canal


The toilets, showers and a little shack at the refuge


The housing is simple wood with a metal roof, not completely closed.


Early morning, and sometimes during the day Howler Monkeys made a lot of noise. They live high in the trees so you can't see them well. But you can definitely hear them, when they argue with their neighbors! It's not that bad, though. You get used to it.


We spent our days planting trees, helping out with work at the refuge, relaxing, drinking fresh coconut milk, and most importantly guarding one kilometer of beach every night from about 22:00 to 4:00, if I remember correctly. Napping during the day is mandatory.

Sea turtle eggs and, depending on the species, parts of the turtle are valuable. If countries like Costa Rica would not try to secure breeding grounds for sea turtles, they would go extinct. Sea turtles are very vulnerable when they lay eggs. Plus, laying eggs takes long and poachers can most of the time easily find the nests.

So we went out every night, traversing the same one kilometer every 30 minutes. When we found a turtle, we took its eggs and brought them to the refuge and built a new nest there. When we encountered a poacher, we would wait for him or her to pass. The idea is to try and be the first at the nest. The unspoken rule is that you leave the finder alone with its nest. No guns, just a machete for safety and perhaps sticks.

I can't show you any pictures of our nightly walks, and no turtles, because turtles only come ashore at night. And they use the moon for navigation. We needed to be dressed darkly and use no light except a bit of red light for writing into a notebook. No flashes allowed.

There are a few different species of sea turtles landing here, but during early July only the Leatherback visits (You can find some pictures here: (1), (2), (3)). It can grow to around 2m and 700kg. We saw just two in all our time, but during high season there are lot more. Both turtles were around 1.6m long. Impressive animals - Huge!

This is the trail of a Leatherback to its nest. The actual nest is a 20 by 20 by 40 cm hole. The rest is dug up sand to hide its exact location.



This is the remains of a fight with the sea. A Leatherback turtle decided to lay its eggs in a bad spot. The waves came in too far. If the nest / the turtle gets wet in process, the turtle aborts its mission, goes back into the sea and takes a new attempt in the next few hours or days. So we fortified the position in hopes to keep the water in check. ...But to no avail. The turtle went back without laying its eggs.


Another day we were lucky and witnessed everything. It was amazing! Such a huge animal. Paddling across the beach, inch by inch. Then it used its back fins to dig the nest hole and put the eggs in. We saw the strain on her face from the exertion. By the way, the head of such a turtle is as large as a human's. I felt deeply in awe. After that the turtle did what looks like a dance and dug up sand here and there to hide the true position of the nest.

The refuge's hatchery

The beach was littered with crabs that would hide in little holes and come out if no one is around. A bit like Whack-a-Mole where they hide when you are near. Another type of crab repeatedly rides in on a wave and tries to catch small insects like flies. Then it stands there and watches and eventually runs back into the ocean. It was a fun pass time chasing them. ... Wave comes, wave retreats, crab remains on the beach and watches around, I run in between it and the sea to try and cut it off. If that was successful, which it rarely was, I'd chase it around and try to catch it :D. And of course I'd just free it again, afterwards. I admit I injured one in the process once.

Marinera crab in its hole





A pineapple plant


We spent the last few days in Puerto Viejo, a very touristy place. Lots of surfers, lots of Germans.





The prime customer in the rescue center is the sloth, because it's too slow to cross the street quickly, and often gets electrocuted while climbing an electric pole.




These volunteers socialize with monkey children. Monkeys need that to grow up healthy.


And then it was already time to go to San Jose, and catch the flight home.






I really enjoyed my time in Costa Rica, and recommend spending a vacation there. The people at the refuge took great care of us and helped us navigate the country.

Thank you Barbara, Johnny, Emilia, Pedro, Eliseo, Alan, Maylin, Elena, Suzette and Claire!

2018-03-09

Retirement Calculator

I made my own little retirement calculator, because I was dissatisfied with how the calculators I checked do the math. And I added a bit more flexibility to play with the numbers.

It's a simple python script: (GitHub link)

    Usage: retirement-calculator [options]
    Optional arguments:
      -h, --help                   Show this help message and exit

      --initial-savings            <USD>
      --working-annual-return-rate <rate>
      --retired-annual-return-rate <rate> 
      --inflation                  <rate> 
      --working                    <years> 
      --retired                    <years>
      --working-annual-savings     <USD> 
      --retired-annual-withdraw    <USD>
      --verbose

The calculation works as follows:

    savings=initial_savings
    for year in range(1, working+1):
        return = savings * working_annual_return_rate

        savings += return
        savings += working_annual_savings
        savings *= (1-inflation)


And in retirement:

    for year in range(1, retired+1):
        savings -= retired_annual_withdraw
        return = savings * retired_annual_return_rate

        savings += return

        savings *= (1-inflation)

To help with picking values for annual return rates and inflation, the calculator provides some historic data.

One consideration I glossed over is taxation. Depending on your account type (brokerage, IRA, Roth IRA, ...) you do or do not pay certain taxes like capital gain tax on your realized gains or income tax on your retirement income. Keep that in mind when looking at the numbers.

The other thing I simplified is that you would normally gradually move your investments towards safer options as you get closer to your retirement date. The calculator assumes a hard switch in annual return rate at the start of retirement.

Note that all numbers are in today's US Dollars. That also means that the calculator assumes you increase your annual savings to match the rate of inflation.

For example, if you work for 35 years, save $6000 a year, assume an annual return rate of 7% during work life and 5% during retirement and 3% annual rate of inflation, you end up with $411020 of today's US Dollars, and an initial annual return of $19351 at the start of retirement. With that you can roughly withdraw $17000 per year for 30 years.

So that's no good.

The difficult part is estimating future returns on your investments.

Playing with the numbers, I'd say if you want to be safe, saving $10000 to $15000 per year seems to be about right. The more the better.

Here is a sample output: (link)

    2017-05-18

    Great Smoky Mountains / Cades Cove Hike

    The Great Smoky Mountains are part of the Appalachians - a system of mountains in the east of the U.S., ranging from the bottom all the way to the top. Notably in the Smokies, you can oftentimes see wild black bears. Bears aside, there are a number of dangerous animals living in Tennessee, e.g. Rattlesnakes, Copperheads and venomous spiders.

    The following photos are from a hike on the Anthony Creek Trail in Cades Cove. At the end of the trail we met a guy who hikes the whole Appalachian Trail from Georgia all the way up to Maine. That is 3500km and takes five to seven months - Holy shit!

    On our way

    Lots of fog and rain on our way up


    Reached the end of the trail

    A colorful tree in the middle of green, brown and gray

    A creepy millipede - Xystodesmidae / Apheloria perhaps?



    At the visitor center - a friend wanted to collect the stamp for this national park.
    Her goal is to visit each national park and collect all 59 stamps.