# Bird Banding 3

This is a follow up to the Bird Banding 1 and Bird Banding 2 problems.

When last we left you, our intrepid hero, you had created the following updated list of bird abundances across sites:

``````number_of_birds = [28, 32, 1, 0, 10, 22, 30, 19, 145, 27, 36, 25, 9,
38, 21, 12, 122, 87, 36, 3, 0, 5, 55, 62, 98, 32,
90, 33, 14, 39, 56, 81, 29, 38, 1, 0, 143, 37, 98,
77, 92, 83, 34, 98, 40, 45, 51, 17, 22, 37, 48, 38,
91, 73, 54, 46, 102, 273, 60, 10, 11, 27, 24, 16,
9, 23, 39, 102, 0, 14, 3, 9, 93, 64]
``````

For your research on bird counts you need to not only know what many birds are at a single site, but also how many birds occur on groups of sites.

Use slices to answer the following questions:

​1. What is the total number of birds for 5 sites starting at site 10?

​2. What is the total number of birds at the last 6 sites? Have Python figure out what the last six sites are, don’t just type in their positions.

You’re going to be doing a lot of this sort of analysis, so it’s probably better to have a function that does it for you rather than doing the slicing yourself each time. Cut and paste the following function into your code:

``````def n_site_count(bird_counts, start_site, number_of_sites):
"""Count the total number of birds at a given number of sites starting
at a given start site."""
start_site = start_site - 1 #convert start site to Python index
sub_sites = bird_counts[start_site:start_site + number_of_sites]
number_of_birds = sum(sub_sites)
return number_of_birds
``````

Use the function to calculate and return the total count of all birds for the n sites starting at the start site. For example, if there are 5 sites and number_of_birds_list = [5, 5, 10, 10, 8], then if starting_site = 2 and number_of_sites = 3 then the function should return the value 25 (5 + 10 + 10). Use the data on the number of birds given in the list above (just copy and paste it into your code) to answer the following questions.

​3. What is the total number of birds for 5 sites starting at site 10?

​4. What is the total number of birds for 7 sites starting at site 1?

​5. What is the total number of birds for 1 site starting at site 23?

​6. Think about what the funtion should do if asked for the total number of birds for 10 sites starting at site 70 (Note: there are only 74 sites). Print out a sentence that explains what it actually does.