The best size for your site depends on the scale of your landscape and the distance over which you can easily see or walk. It also depends on whether you are observing animals or only plants. For plants, a site is the area that surrounds the individual plants you are observing. For animals, a site is the area where you look for the animals on your checklist. If you are observing both plants and animals, your site(s) can serve in both of these ways.
If you are observing both plants and animals or only animals: Because you will be reporting observations of animals you see or hear in your site, your site can include the area that you can see and hear well while standing still or the area that you can walk in a relatively short amount of time. If you are observing in an open grassland or near a body of water, your site might be the maximum recommended size (15 acres), because you may be able to identify animals that are far away. In contrast, if your site is in a dense forest, it might be relatively small, as you may not be able to identify species at great distances.
Even if you can identify animals over a large area, an area should be divided into different sites if it includes habitats that are obviously different. For instance, if you are making observations at a pond in a meadow, the pond and the meadow should be registered as separate sites. In that case, just report your animal observations for the site at which you saw or heard them, for example, at either the pond or the meadow.
If you are observing only plants: For plants, the size of your site does not matter much as long as the conditions are pretty similar throughout your site. If you are observing just one plant, your site can simply be the small area immediately around that plant, say within 3 feet of the plant. If you are observing several plants near one another, you can consider them all to be at one site, as long as the site conditions are pretty similar and the site is no larger than 15 acres or 6 hectares.
When selecting the plants to observe at your site, you will want to strike a balance between how much time it will take to walk between plants, while ensuring that the individual plants that you are observing are not too close together (see How many individual plants of the same species should I observe?). Your observing locations should be divided into different sites if their habitats are obviously different.
If you are observing a large number of plants or animals: If you are observing more than 20 plants and animals at one site we suggest breaking this up into separate sites in Nature’s Notebook, as sites with many species overload the Enter Observations page. For example, if you have 10 animals and 15 plants that you observe in your back yard, you could break this up into “Back Yard Animals” and “Back Yard Plants”. For people observing more than 20 plants (either as an individual observer or as part of a research project), you can break up large sites into smaller ones based on geographic or environmental features, or sub sites related to your study. For example, you could split up a lake bog site into “Lake bog lowland”, “Lake bog highland” and “Lake highland”.