Thoughts on Fledging Age

[avesrun]

For some reason I had in my mind that fledge age for Purple martins was 26-32 days of age. I have a late nest here in Iowa that consisted of 4 nestlings. Adult martins for the nest are both sy/ second yr .
One nestling was lost early I believe due to sy male removal. The three remaining nestlings have survived well . I've watched thenest rather diligently since oldest of the young reached 26 days of age (incl weekly nest checks). I observed the first of the three young fledged yesterday at 31 days. The other two have yet to fledge. They're still getting fed nice big dragonflies by parents but at reduced frequency. I was double checking Project Martinwatch info and read that fledge age can range from 26-35 days rather than 26-32 days which was stuck in my head for some reason.
Have any landlords experienced much fledging beyond 31 days of age? First time for me; most seem to go 28-30 days. Thanks for any thoughts!
TimG-Iowa

[Dave Duit]

Hi Tim,
Most all my babies fledge at about 30 days. Maybe it is a second brood, but that wouldn't make sense with an SY pair. I'm as confused as you on this one. I still have two nests that need the babies to fledge and it also seems like they have been around longer than 30 days. I do know that the parents will start to hold back on the feeding schedule in order to get the youngsters to fledge and maybe your observation of this at the satelaite Purple Martin Lake are spot on. Keep us updated.

[bwenger]

Hi Dave,

I have noticed some long periods for fledging as well, and most seem to be at the end. I am thinking that some of this occurs since the nestlings don't have the encouragement to leave the nest as they do when the birds have a lot of activity going on around them. From what I have heard from the Forum and other reading, that the earlier the birds can fledge the higher percentages of success the young have and thus a longer life.

[Dave Duit]

That sounds very logical. Good insight.