A general point: renting a car in Costa Rica, and many other birding destinations, it is very worth to be sure about details of car hire insurance such as excess cover and damage to finer parts of the vehicle, like undercarriage, windows etc and collision damage waiver (CDW). During car hire online it is often difficult to impossible to find what exactly the insurance covers. Companies and / or their staff at the counter in Costa Rica try selling / pressuring to buy extra insurances. This can cost substantial sums when you hire a car for, say, a 14 day holiday.
The point is: in many countries, extras of insurance are already covered by credit card or private liability insurance. Otherwise, diverse companies online offer extra insurances for a fraction of the cost of car hire companies. Check this beforehand. This can save substantial money on car rental and / or worry what happens if you, for example, damage underside of our rental car.