To land a career as an ecologist, a bachelor's degree in a life science is a must. Biology and chemistry are common choices, but these days more undergraduate programs are branching out (pun intended) and offering degrees in environmental science. Some of these degrees come with an emphasis in a particular field like soil science, climatology, zoology, or anthropology.
The degree you choose will inevitably come with its fair share of math and statistics courses, but the ability to crunch numbers in your sleep will almost certainly come in handy later, as a lot of data collected in the field needs to be plugged into various fun formulas and algorithms before you can make accurate predictions. Those of you who break out in hives at the sight of a calculator need not apply.
Most undergraduate programs will have research opportunities for their students, allowing them to work on projects alongside a professor. This sort of work won't only give you valuable experience for the hands-on parts of an ecology career, but will also let you peek behind the curtain and learn about the methods behind research itself.
Getting to work before graduating can get you dirt under your fingernails and mud in your ears—and in this field, that's a plus. Any experience is good experience, so keep your eyes peeled and ears open for those opportunities to get down and dirty.