First off, it is essential to read the directions on the website. As in life itself, all bets are off otherwise and I’m not going to repeat information here.
So, starting with an export file of all your sightings from Wildlife Recorder, say, make use of the Omit column name to isolate data that has no Birdstack equivalent. Rename all the other columns as per instructions. Be sure to replace all 0’s in the “Number observed” column with X’s; convert dates into the format you’re happy with.
If, like me, you’ve changed full species names to your own shorthand, it’s probably easiest to undo this in WR itself. Otherwise every time you import, you’ll have to fix up ambiguous records. And importing will probably be a multiple-pass process because of the 150k limitation on file size.
Fine in theory; horrible in practice: try changing copious instances of oystercatcher to Eurasian oystercatcher in a file also littered with black, South Island, variable, pied and sooty oystercatchers. It really was easiest to change the names in Wildlife Recorder but a pity that Birdstack didn’t import on scientific names.
I have a hell of a lot to change. Let’s see how it goes…