The hooded pitohui makes a variety of calls, mostly forms of whistles. Its song is a variable collection of three to seven whistles, which can slur up or down with hesitant pauses in between. Usually the song begins with two similar notes followed by an upslur. It also makes an "tuk tuk w’oh tuw’uow" call, two whistled "woiy, woiy" notes, two downslurred whistled "tiuw tow" notes, and three whistles "hui-whui-whooee", which increase in volume.[10]
In honor of Gun Gale Online somehow getting a second season https://www.youtube.com/watch?v=jrGa1Vr7-5M (i had lots of fun with it even thou i've never watched anything else SAO, also the LN is by the author of Kino's Journey!), please consider the "Calls" section of the wiki article about the Hooded pitohui (a cool poisonous(!) bird).
I like to think the person writing this had fun with it, but the delightfully detailed and technical sounding language also seems entirely earnest in its seriousness, which I also like.