It depends on the source of the text. If it's modern, it's a bit odd. I'd guess, like Brenda, that it's a typo and should be 'petty'. However if it's a much older text, there are some archaic meanings of 'pretty' which might fit - perhaps 'considerable' or 'trivial'. It's hard to guess without knowing the source.

One meaning of "pretty", having nothing to do with physical beauty, is "very fine" or "lovely". It is often used in an ironic or sarcastic way so that the intended meaning becomes the opposite of what it says. So, while "our pretty tasks" literally means "our lovely tasks", the actual intended meaning is probably "our not very lovely tasks". To be certain of this, I would need more context. It is not uncommon to use "pretty" in this way.

Are you sure the word is "pretty" and not "petty"?

I couldn't help but notice your profile pic. A very interesting part of our history. I remember learning about it when I was at school. I actually did a project where I interviewed the pilot. Can't remember his name. :)