Counting from multiple sheets

Sorry if this is the wrong section, but I am not sure how to do what I need. I have attached an example file with three sheets. The first sheet contains the information for bats captured at a given site, date, and net. The second sheet contains additional information for sites including dates surveys were conducted, and the height, length and placement of each net used at that site. The third sheet is an example of what I am looking for, I created it manually using the information from the two sheets, but would like some automated way of doing it because I have many many many more records. I was able to create what I'm looking for (i.e. site, date, net, net length, net height, net placement, NUMBER of bats captured in that net, on that date, at that site) but only for nets with bat captures, but I also need to include the nets that did not capture any bats. Again I have so many records that doing it by hand really isn't an option. These table were created from an MS Access database so if it would be easier using Access I would not be opposed. Please let me know if you need additional information, and thanks so much for you help.