Landbird populations and species compositions on the islands can change from year to year, depending on mainland species that reach the islands, changes in habitats, competitors or predators that arrive or leave the islands, or areas that are disturbed by people. Most of the bird species probably have experienced a loss of preferred food and shelter due to the alteration of the islands' scrub habitats.
Did You Know?
The endemic island deer mouse is the only native terrestrial mammal common to all the Channel Islands and is larger than mainland deer mice. Densities of deer mice on the islands can be greater than anywhere else in the world. This makes you happy if you're an owl, but not if you're a camper.