1) Problem description:
Prompt the user to enter the name of a text file. Each line of the text file has the name of a species of bird. Count the number of times each species appears in the text file. Print out the bird species and their counts. 

2) Input format
We need a filename in the current working directory as a string. 
The other input is the text file identifies by the filename. The name of the species of birds is on each line and separated by a newline character. The file should be in the working directory and its name must end in ".txt", otherwise, the program cannot process the file.

We have to assume that each of text corresponds to a bird species. If the user provides an invalid file, including:
    - data entry mistakes, such as entering "Baltimore Oriole akjbakd1243"
    - or putting two species on one line
    - or naming a file that contains non-test data.
We cannot do anything about that ahead of time. The program will probably error out. 

3) Output format:
Print each unique bird species (String) followed by the count (integer) to the console.

4) Exceptional conditions:
- The user could enter a filename that doesn't exist.
- The file might not have any text in it.
- The file does not have the .txt extension. 

5) Input samples:
"birds_small.txt" is an example of a valid filename assuming it exists.
The contents of the file would look like this:
    White-eared Hummingbird
    Townsend's Solitaire
    Townsend's Solitaire
    Yellow-fronted Canary
    Chestnut-fronted Macaw

6) Output samples
The following is printed to the console: 
    White-eared Hummingbird 1
    Townsend's Solitaire 2
    Yellow-fronted Canary 1
    Chestnut-fronted Macaw 1