My hypothesis–tide levels have an influence on the number of American herring gulls at White Rock beach–primarily touches on the process of predation in relation to trophic levels in intertidal habitats with an elevational gradient. For example, primary food sources for American herring gulls are crustaceans (e.g., crabs), gastropods (e.g., snails), and molluscs (e.g., clams). These food sources are more difficult to find during periods of high tide as they typically reside in the sandy areas on the ocean floor. The sandy areas that are exposed during high tide are poor sources, as these organisms would be dried up due to lack of water reaching them. Therefore, during low tide, when the waters have receded and part of the ocean floor is exposed, there is a richer variety of these food sources that are more easily accessible for the gulls.
Potential keywords that I could use to describe my research project include:
- Intertidal zone
- Elevational gradient
- Herring gull distributions