June Chicks

It looks like our bird friend has been successful raising four chicks in the nest on our porch. They are getting quite large and one has been perched at the edge of the nest for a few days like it might lean over and fly away.

Last year we had two sets of chicks under the same eave, and none of them made it so I am crossing my fingers for this group. Last year the mother bird began removing chicks from the nest when they were too young to fly, carrying them with her beak down to the ground and leaving them there to die. I read that this often happens with chicks that are sick or have some genetic flaw, and it broke my heart. The second group seemed to be fine for a while, but at a certain point we realized there was no activity in the nest and when I took a peek up there the chicks were still there, but dead and covered in dust. Second broken heart. 

It appears that there are two adults taking care of the current nest. Does that sound right? Two birds fly back and forth with worms and bugs, and two birds hang out in the tree next to the nest chirping whenever anyone gets close. I managed to get a shot of them together in a nearby tree.

Does anyone know what the dynamics would be between these two? Would they be two females? A male and a female? Two males?

I'm pulling for these little chicks, hoping they will fly off soon. I imagine another set of eggs will appear in the nest not too long after this set is gone.