Last year I had the chance to observe a couple of yellow-bellied Sapsuckers at work. When they left their feeding site, others would come to feed. There was a red Squirrel, a red-eyed Vireo and a ruby-throated Hummingbird that visited the feeding site. Only the ruby-throated Hummingbird was tolerated at the feeding site when the yellow-bellied Sapsuckers were there. If you are interested in seeing some photos, see this link to my eBird list. https://ebird.org/checklist/S142263900?_gl=1*1byaunl*_ga*ODQ3NDc2MDY4LjE3MTE0ODc3MzY.*_ga_QR4NVXZ8BM*MTcxMzQ1OTI2NS44MS4xLjE3MTM0NTkyODMuNDIuMC4w&_ga=2.65895214.1472895500.1711670921-847476068.1711487736

I have observed the different species of animals that utilize the woodpecker's holes for living, for example saw a Screech Owl emerge from a woodpecker made hole during a bird count. In California saw some flying insects and birds taking advantage of the sap coming off the tree when a sapsucker flew away. If there were not to have woodpeckers I think part of the food chain will change based on what woodpecker can "unearth" by digging onto the trees.

To me, woodpeckers are one of the most successful birds in different environments, using local resources while providing shelter and food for other animals. Last week, I saw a European Crested Tit in the forest using a woodpecker nest. It was wonderful to see how each organism is linked to the others in a very complex interactions for the benefit of all.

I don't see woodpeckers enough to observe how they fit into the ecosystem, but I know that I would be very sad if I never saw any more woodpeckers, and I would guess that there would be an overpopulation of the insects that are eaten by the woodpeckers.

I will try to think like the food web example given.  Thanks for explaining all the related photos,  I couldn't have figured out what the diagram was detailing until it was explained. Pileated Woodpeckers leave large openings, usually square, in trees and often make more than one during their nest building work.  No doubt other cavity nesters and rodents use them. The rodents feed owls and hawks. The Pileated Woodpeckers also strip large areas of bark off trees in their search for ants, leaving some of the available protein for other woodland creatures. So, I only got to 3 trophic levels and couldn't figure out how these things feed nutrients back into the forest.

Woodpecker as architect is simply mind-blowing. I got to know entirely new thing. I observed piculet on an invasive plant lantana ( in bushes). Woodpecker I always observed at higher perches. Definitely the higher best would be used by many animals but the bushes and woodpecker relation is something I would explore now.