The Relationship between Migratory Birds and Abiotic Factors

Birds in an urban lake were studying during the winter to examine species diversity and bird density. Bird density refers to the number of birds in anar area. Abiotic factors examined were water temperature, nitrates, phosphates, and dissolved oxygen.

GPP stand for "gross primary productivity" and is a measure of the amount of plants and algae present in the ecosystem.

bird density

1. What factor is displayed on the X axis?


2. What are the independent variables shown by the lines on the graph?


3. What is the dependent variable being studied?


4. Which variable changes the least during the winter period?


5. In what month was bird density the highest?


6. Why was bird density low during fall and spring months? (Hint: See the title of these research.)


Scientists also measured water temperature and oxygen in the lake and water temperature.


dissolved oxygen

7. Summarize the relationship between water temperature and dissolved oxygen.


8. Why would the amount of dissolved oxygen be low in winter months? Consider the plants that live in the lake.


9. Both of these graphs are related to a study on bird density. What question were scientists trying to answer?


10. How are these variables related?