Hello and welcome to BYC!
Diarrhea is common when it is hot outside. This picture appears the bird is over heated and possibly a bit dehydrated, maybe not eating enough either.
BUT...it depends on whether or not the bird ALWAYS poops like this. Birds will occasionally poop all kinds of nasty poop, depending on what they ate in the last hour, how stressed they have been or if they have a bit of indigestion. But if they poop like this ALL the time, there is definitely something going wrong. I try to judge my birds poop first thing in the morning from the over night poop. It tends to reflect the overall health of the bird since it is a collection of 8 or more hours of poop.
So if it is pretty dry over night and looks ok, but a bird just left one like the picture above, it's no big deal. It is probably the heat and over the next few weeks, the birds will adapt to the heat.
If they are like this all the time, the bird could be egg bound, have a crop problem such as slow, sour or impacted crop, they could be internally laying or have developed reproductive cancer. Especially liquid green poop. Not only does it turn forest green when they don't eat, but internal infections from internal laying, cancers and liver disease will cause liquid green poop. Worms can cause diarrhea, but not always. So I wouldn't suspect worms, but it is always a good idea to keep everybody wormed each year.
So check the over night poop and see who is pooping what. And keep us posted!
