[Mnbird] Yellow-bellied Sapsucker Nesting Question

[Molly Miller]

I had Yellow-bellied Sapsuckers nesting in a tree on our property. Only the male worked on the nest cavity, repeatedly bringing beaks full of "sawdust" out as he dug. You could tell his progress by how much of him stuck out in the process. 

Eventually the male and female brought food to the hole, and then I could hear the nestlings begging. During this phase, the male continued to come out periodically with his beak full of sawdust.

Was he enlarging the nest cavity as the kids grew? Or did fecal sacs end up inside and he grabbed them plus sawdust? Based on the noise level of their begging, there had to be 3-5 kids in there. Did they eat all the fecal sacs? (I may have seen the female carry out one fecal sac in all their time in the nest.)

Also, the adults would often gather protein (bugs) and then go to their sap holes, before taking the food to the nestlings. I don't know if the always did this or not. Were they "dipping" the bugs into the sap to train the kids on the flavor, or to add nutrition or energy, or what?

As a side note, the mom and dad looked like MSP International Airport trying to keep up with their feeding. Depending upon where I stood to watch them, they would fly right over my head on the way out of the nest and off to their meal gathering. Nothing kept them from their mission.

Thanks for any insight into this sawdust, fecal sac, and sap behavior. 

Molly Miller
Inver Grove Hts
Dakota Co