The point of view is third-person limited omniscient. The omniscient view extends to all events and the novel's exposition, but it is only into Jonathan's heart and mind that we are taken. The effect is to bring us closer to Jonathan than to the others in the novel. We can relate to him very strongly because we share his feelings as well as his experiences.
The literary technique "point of view" is generally described in three categories: first person, second person or third person.
First person is the narrator, or writer or speaker, talking about himself or herself. "I" did this, and "I" did that.
Second person is the narrator, writer or speaker describing what is happening to "you."
Third person is talking about someone else, using words like "he," "she," and "they."
Jonathan Livingston Seagull is written in third person. A narrator is telling you the story about Jonathan, so Jonathan's name is used many times, along with descriptions of what "he" is doing.
There is another element to this, however, and that is the "viewpoint," which is slightly different. This is a description of the focus of the narration. In Jonathan Livingston Seagull, the viewpoint is clearly focused on Jonathan. The whole story is about what Jonathan is doing, thinking, and feeling. There are no conversations that do not involve him. We, the readers, are not told anything that happens to anyone else, except what Jonathan sees and experiences. This viewpoint keeps the feeling of the book very close, very tight, so that our experiences are Jonathan's experiences, and nobody else's.
Many novels may use a third person narrator, but will have split viewpoints, as the novel jumps from one scene with some characters, then tells us about someone else in another time or place, then jumps back again, etc. This keeps the reader completely involved in everything related to the novel, but not as closely tied to a single character.