Parrots know when they can and can’t raise a clutch. Light plays a big role, as all captive parrot species are diurnal. They can’t collect food in the dark, so longer daylight hours means more food for hungry chicks.

Weather will play a factor, as well. Eggs must be kept at a certain temperature. In cooler temperatures, the female can keep them warm; however, when the temp is hotter than what is need for incubation, she can’t cool them down. Also, rain can play a factor. Depending on natural habitat, for some parrots, rain signals a good food supply, so chicks can be well-fed, while for others, it means flooding of nest holes. Yet, sometimes, prolific breeders in captivity, like cockatiels will breed almost any time, but it doesn’t mean that every clutch will be successful.

Side note: Macaws are parrots.