What kind of techniques does ecologists use to gather data on birth rates, death rates, imigration and emigrat

Question

What kind of techniques does ecologists use to gather data on birth rates, death rates, imigration and emigrations in the US?

Answer 1

I have a real problem with your question--I can not tell what your are asking??

Answer 2

There are a couple different techniques, but the standard is some sort of survey. Assuming that you can mark or somehow recognize individuals, periodic surveys allow you to get a measure of variations in a population. For some organisms, direct measures of birth rate can be made (nest surveys to see # of eggs, # of hatchlings, # of fledgelings, etc.). Death rate can be calculated by measuring the number of a particular age cohort in one time period, and then the number of that same cohort in the next time period. The percentage decrease in the cohort, over the time period involved, is the death rate for that particular cohort. Immigration and emigration can be harder to measure unless you have a clear knowledge of birth and death rates; then any "extra" individuals gained or lost are presumably due to immigration or emigration. This is a bit oversimplified, but it can give you a place to start.