If you created fractions out of your bird data, you could now try to turn those factions into percentages. Maybe you could then create a pie chart! You would need to know the degrees in a full turn (360) and divide that by 100. This would mean each percent equals 3.6 degrees. So my Pigeon part of the pie (30%) would be 108 degrees. My House Sparrow part (70%) would be 252 degrees. 108+252 = 360 so the full circle would be filled.
You could also take your original data (3 Pigeons and 7 House Sparrows) and calculate the degrees from there. 3 + 7 equals 10 so 360 degrees needs to be divided into 10 parts giving each part 36 degrees. So 3 Pigeons would be 3 x 36 and 7 House Sparrows would be 7 x 36. Pigeons would be 108 degrees and House Sparrows would be 252 degrees.
I have included a video below.