D. Answer the following questions based on your data

Results and Conclusions

C. Using your data from Activity B, fill in the graph below to show how the amount of precipitation relates to the percentage of eggs hatched.

XIX. Experiment on Limiting Factors

Does Precipitation Affect a Bird Population?

Analyze data to find the effect of precipitation on the hatching of eggs by sand hill cranes, one of the tallest North American birds.

A. The following table shows the number of sand hill crane eggs hatched in the wild during an eight-year experiment. The amount of rainfall and snowfall during each of the eight years was also recorded. Study the data.

TABLE 1. Sand hill Crane Eggs Hatched

Year	Number of Adults	Number of Nests	Number of Eggs Laid	Number of Eggs Hatched	Rainfall (cm)	Snowfall (cm)
					1.4	1.4
					2.5	5.5
					7.8	3.0
					3.2	0.7
					2.8	1.0
					3.5	0.5
					2.1	0.6
					6.4	2.4

B. Fill in the correct information in the table below using the data from table 1. Determine the total precipitation in each year by adding the amount of rainfall and snowfall. Find the percentage of eggs hatched in each year. To do this, divide the number of eggs hatched bythe number of eggs laid, and then multiply by 100.

Year	Number of Eggs Laid	Number of Eggs Hatched	Rainfall (cm)	Snowfall (cm)	Total Precipitation (cm)	Percentage of Eggs Hatched

Precipitation (cm)

0 10 20 30 40 50 60 70 80 90 100

Percentage of Eggs Hatched

1. In which year was the precipitation lowest? Highest?

2. What seems to be the relationship between the amount of precipitation and the number of eggs hatched? Explain your answer.

3. On the basis of the data, does precipitation seem to be a limiting factor for the sand hill crane population? Explain your answer.

4. Does the effect of precipitation on the population seem to be dependent upon the density of the population? Explain your answer.

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