What is seen in the middle of March and April that cannot be seen in the beginning or end of either month

" R " can be seen in the middle of March and April that can't be seen at the beginning or end of either month.

A brief explanation :

 Riddle asks to find out the objective which can be seen in the middle of March and April.

 In the first strike of the mind, we may think about what incidents or climate changes take place in between those two months. But it isn't that!

        March > m a R c h

            April > a p R i l

 " March " is a five letter word and so is " April " , and both the words have " R " as the common letter in the third place from the beginning or in the middle of the words.

 To say , there is no other letter common in either words orderly.

I read this somewhere

so are we writing a song for you or are we making characters for you.