Between 8:30 and 10:00 I shot 739 photos. It's easy to do when your camera can shoot 8 frames a second.
In the first round, I culled out (deleted) 412 or 55% of my shots. These were the easy ones to delete. They were out of focus, over/under exposed, the bird was behind a branch or facing the wrong way. I didn't have to look close to see that they needed to be sent to the bit-bucket.
This initial culling process used to be painfully slow. Lightroom took a long time to build previews of the RAW photos to display on the screen. Depending on how many photos you imported, it could take a while to build the previews. The best thing to do was to go get a cup of coffee and relax. A new Lightroom Classic feature added in version 7.2 makes this process a significantly faster than before.
When importing the photos from the memory card, I choose the “Embedded and Sidecar” option in the preview generation dropdown. Lightroom will use the embedded jpeg preview out of the raw file that your camera generated. I can immediately start the culling step using these embedded previews without having to wait on Lightroom.
Lightroom will display "Embedded Preview" in the lower right of an image so you can tell that you are viewing the preview from the camera.
At some point in your Lightroom process, you will want to work with true 1:1 previews. When you are to the point where you need to zoom in to pick the best photos, go to the Library module, grid view, select all the remaining photos and click the Library menu. Select Previews and Build 1:1 Previews. It will take less time because you are building fewer previews.