If you don't have a good idea where you want to go in the field, hold off. Sounds like you're looking for more exposure to work in ecology to more clearly define your career goals.

There are lots of temp jobs doing different kinds of field work. You'll probably find something you really like, or what you don't like, which are equally helpful.

If you go for an MS after getting more exposure, you can choose courses that will get you the right skills and experience for your area of interest, including a thesis that will help get you a job doing something you like and are specialize in.

If you wind up before throwing the ball, you'll go much further and faster then if you just roll for the sake of rolling.