In all, then, breeding Purple Martins have four distinct categories based on age and sex. There are several competing hypotheses as to why Purple Martins have evolved this delayed plumage maturation, fostering passionate debate about the evolutionary reasons for such traits. Several behavioral cues can help decipher this confusing mix. They make this sound with their mouth wide open. Males also frequently fly behind their mates when a pair flies to the ground to gather nesting material or to nearby vegetation to pluck green leaves.
Males also chase females during courtship and pounce upon females during copulation.
The population of Purple Martins, regardless of the bird's adaptability, has certainly been affected by human activity. The long term trend is one of great loss. Historically, the Purple Martin used natural cavities for nest sites. The western population still makes use of such sites. The eastern region of the US, however, presents a different story.