The tree trimmer at the center of a federal and state investigation into the destruction of nests and slaughter of baby birds in Oakland said Thursday that he “screwed up” because he allowed his crews to chain-saw trees even as baby birds were falling out.

Ernesto Pulido of Bay Point said he is so regretful now that he realizes birds were harmed that he phoned the International Bird Rescue in Fairfield and offered to pay for the care of the surviving black-crowned night herons.

Pulido said that on Saturday he did not think any birds were being hurt and that crews had picked up some of the small birds and set them aside. He called himself an animal lover who owns chickens, rabbits and dogs and said he would never have intentionally injured the birds.

“I screwed up,” Pulido said. “They were trees I probably shouldn’t have worked on. I’m a human being like anyone else. We all make mistakes. I’m not hiding anything. I’m responsible.”

Pulido was the supervisor for a crew of tree trimmers hired Saturday by the U.S. Postal Service’s Civic Center Annex in Oakland. The post office ordered trees containing the nests of egrets and black-crowned night herons, species protected by the U.S. Migratory Bird Act, to be cut because the nesting birds were defecating on mail trucks.

Tree trimmer apologizes for Oakland baby-bird fiasco