The bluebirds are fed 7/12.
First) You need to find a common denominator for the both of these fractions, which is 12.
Second) You need to multiply 1/3 and 1/4 to have a denominator of 12. The equivalent fractions for them are 4/12 and 3/12.
Last) You just add the numerators together and you get 7/12 ( you don't need to simplify since it already is in simplest form)
Hope this Helps!