Re: work in conservation with a young family?
My answer isn't going to be too helpful as I'm not a mum and I'm trying to find work myself!
Where I'm on placement at the moment, in a local council, two of my colleagues work as ecologists in the sustainability team. They work on flexi-hour job share, which means they work 2 and half days a week each and can pretty much come and go as they want, as long as they do a minimum number of hours in their allocated 2 and half days. They can come in late, or leave early as they need (i.e. when their kids are ill or their after school activity has been cancelled that week etc.)
It's mainly office work, but you get to do a bit with Bats, Dormice, Reptiles, Great Crested Newts, Badgers etc. depending on where in the country you are.
Hope this is a bit helpful!