Answer :
I think about 60 cause 80 divided by 16=5x16=80 and 16-4=12=12x5=60.
we know that
using proportion
[tex] \frac{80}{16} \frac{humming\ birds}{oz} =\frac{x}{12} \frac{humming\ birds}{oz}\\ \\ 80*12=16*x\\ \\ x=\frac{80*12}{16} \\ \\ x=60\ humming\ birds [/tex]
therefore
the answer is
[tex] 60\ humming\ birds [/tex]