Unsuccessful attempt No 1

Have been trying to get Darrell to call me MaMa or Mummy but not successful. =(
The closest he ever get to calling me is sometime back he is crying in hunger and i am rushing to make him his milk and he let out a loud "MAAAARR MEEEE!" but i reckon he is not really calling me but more like out of desperation let out any sound he can think of...hehe

Mummy: Darrell call Mummy..
Darrell: Bird... (he is able to pronounce bird now, mil has been showing him birds flying in the sky and telling him its bird. Ever since he know how to say it, cant stop saying it)
Mummy: Nono...call Mummy.
Darrell: Bird...
Mummy: Yes yes..Mummy know you know how to say bird...now say Mummy..
Darrell: Bird...
Mummy: ...........