Robert Woodward, the Washington Post's Watergate reporter, who appeared last night at the annual Boston Book Fair, said that when President Ford's administration came in, some of the reporter's important sources went out.

"Not all of our best sources are gone," Woodward said, "but we did lose some of them." Woodward would not say whether he and Post reporter Carl Bernstein--with whom he unraveled much of the Watergate scandal--had lost their top source, "Deep Throat."

Speaking with Woodward before a cheering crowd of 3000 at the John B. Hynes Veterans Auditorium, Bernstein criticized the Nixon administration's handling of Watergate.

Press' Conduct

"The White House singled out--and with great success--not the conduct of the men surrounding the president himself, but the conduct of the press, especially the Washington Post," Bernstein said. "More distressing, it worked."

The investigative reporting team, which recently co-authored a Watergate chronology entitled "All the President's Men," spoke about the way in which they investigated and broke open the Watergate case.

"We covered Watergate in very much the same way we'd cover a fire or a local police story," Bernstein said. "And we covered it the only way we knew how."

Woodward spoke of the endless phone-calls he and Bernstein made. Once, Woodward said he tracked down Howard Hunt over the phone and asked him if he were involved in the Watergate burgulary. According to Woodward, Hunt screamed "Good God," and slammed the receiver down.

"There was a certain I-have-packed- my-bags' tone in his voice that stimulated our curiosity," Woodward said.

The reporters said they are taking a six month leave of absence from the Washington. Post to finish their latest book, "The Last Hundred Days." The book, they said, will be a day-by-day account of the last days of the Nixon administration. "We hope to tall to all the principals," Woodward said, "except perhaps Nixon.