One of the keys to sharp bird photos is a fast shutter speed. Keeping with that theory, a fast shutter speed for bird photography is my priority. In most cases, I am striving for 1/1000 or faster. There are cases where a slower shutter speed may work if the bird is perched and 1/1000 or faster is best and will work fine for a perched bird as well
In this photo of a crane taken in Leesburg, Florida I was not quite a 1/1000, but the bird was walking slowly. My settings were 1/800, F2.8 ISO 160.
In my second photo, the robin was jumping around a lot so I was at a faster shutter speed but caught her when she was still on the branch. My settings were:
1/1600, F4.0, and ISO 800
Here are three methods I use to get the desired faster shutter speed for my bird photography.
The easiest mode is Shutter Priority and will work for any camera. The benefit is that you have full control over the shutter speed to ensure you have 1/1000 or faster. However, this comes at the cost of the camera adjusting the Aperture and ISO with no input from you.
To improve using Shutter Priority metho, you can also set the ISO to manual and set it to a value your camera can use without adding excessive noise. For most cameras that is around 1600 or 2000. You can even go higher, but realize more noise will be introduced. Then when adjusting the shutter speed the camera will use the Aperture to compensate for the correct exposure.
This is the hardest mode for bird photography, and I seldom use manual mode. I only use full manual mode when the lighting conditions are not going to change. If I am taking a photo on a specific spot and not going to point my camera in a different area then manual mode might be my choice.
This is one of my go to modes for bird photography. My Canon R5 and Canon 5D Mark IV both have a setting to limit how low the shutter speed can go. So, I set the minimum shutter speed to 1/1000 and either let my ISO be in auto or a high ISO such as 1600. I can then adjust my Aperture to get the effect I want.
Bottom line you can see the common thread in all my options is a fast shutter speed. That is my priority. I use all three modes and in each I strive for 1/1000 or faster.