Hi Beaufort,
Sorry for the confusion. The file I was talking about was the object library file. Your problem has nothing to do with SimObjects. Since you have the proper object libray file, there is another possiblity. You need to check that you have the latest version of the SAK - Sea Plane Bases V2.1 scenery package which places the dolphin, gull and other objects at the EXI SPB location. That package contains a folder named SAK Seaplane Bases which should be enabled inside your sim's scenery library.
I assume you have it enabled or you wouldn't see the birds. However, please check the SAK Sea Plane Base EXI.bgl (the placement file that actually places the dophin swimming in front of EXI) that is contained inside your SAK Seaplane Bases folder. It should be dated 5/29/18. Inside that same folder you should have a version.txt file that contains the following:
SAK - Sea Plane Bases V2.1 (Refreshed 06.10.2019)
Scenery by Brad Allen and AI Traffic by Dex Thomas
If the SAK Seaplane Bases folder checks out, then you should see the dolphins swimming. If not, you need to download the latest SAK - Sea Plane Bases V2.1 scenery package from the RTMM Scenery Library and replace you SAK Seaplane Bases folder.
Rod