I think there's a few things at play.
The heat is hard on chicks, they can't regulate their body temps very well I'm told.
The water holes are pretty dry, so I wonder how flightless birds are to get something to drink? I don't know when they learn to eat bugs and get their moisture from them, probably pretty early.
The lack of cover would seem to make them pretty vulnerable to avian predators also.
Add it all up and there will be fewer birds this year because of the drought
