Hiya,
There are a lot more people on here that will be better qualified than me to give advice, but just some thoughts
I assume that it is the RSPB site there? If so, take a look at the site information for things like recent sitings. That may help you decide what areas to target depending on how long you have. There is a bit of a commentary on there that gets updated from time to time (frequency seems to depend on the reserve) with what was seen where.
Out of the 2 lenses, the 70-300 will be your friend
. I don't know the reserve so not sure how far away you are from things, but unless it is really far, I am sure you will get some good shots with it.
I would use the tripod rather than the monopod personally just because I expect that you will be at the limit of the range of the lens a lot (but could easily be wrong). If you are taking a spotting scope, use that on the monopod.
Camera settings will probably depend on the light and how much the birds are moving. The thing I was always told was focus on the eyes first and foremost (sorry if that is obvious/you already now this). It doesn't always work that way but it is a good start
If it is the 70-300 nikon, then you will be at F5.6 most of the time (unless you don't need to go to the full 300mm obviously
). I know I end up on that most of the time!
I hope the weather is good for you and I think I saw on the RSPB site that there have been sightings of Kingfishers there. Would love to se them myself so hope you have a good day and look forward to seeing some shots
