Simple past tense and past participle of bird.(verb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "birded" in a sentence
"On the way back to the gatehouse I birded the birders at Stage Island Pool but since none of them were looking through their scopes and some were sitting listlessly on rocks, I intuited that the gull-billed tern was not present."
"I birded up there with a guy from Sydney until it was too dark to see any more."
"He finished up in a red-birded helmet, playing in a half-filled stadium in the sweltering Arizona desert."