Sounds of the sea

Lately, Ivy has been making these high pitched, ear splitting dolphin like sounds. She seems to be really happy about it and she isn't screaming so we are ok with this. She does still scream an abnormal amount of time during the day, but this dolphin sound has recently come about and is pretty funny. The screaming, however, is really getting old, it exhausts me. Screaming from 5 til around 7, when I lay her down in her snugly gown and shut her door. She falls asleep immediately. I get her up around 9 and feed her and back to bed she goes. She then sleeps all night. Around 530, or so, we hear her singing in her crib. She is apparently summoning the dolphins.