WASHINGTON (Reuters) - Conservative activists picked Senator Rand Paul on Saturday as their preferred presidential nominee for 2016, in an early but often unreliable snapshot of the Republican Party's base.

The Kentucky lawmaker, whose father, former U.S. Representative Ron Paul, ran for president three times, topped the annual straw poll taken at the Conservative Political Action Conference.

Paul captured 25 percent of the vote, narrowly beating out Florida Senator Marco Rubio, who earned 23 percent.

Rick Santorum, a presidential candidate in 2012, finished third and New Jersey Governor Chris Christie, who was snubbed by conference organizers, came in fourth.

Participants in the three-day gathering are often younger-than-average Republican voters and their preference for Paul reflected the libertarian bent of that voting bloc. More than half of the 2,930 people who cast ballots were between the ages of 18 and 25.

Many attendees sported "Stand with Rand" stickers, intended to show appreciation for the senator's recent 13-hour speech on the floor of the Senate objecting to President Barack Obama's policies regarding the use of military drones.

There were 23 names on this year's ballot, including two Republican governors who were not invited to attend the gathering - Christie and Virginia Governor Bob McDonnell.

Former Florida Governor Jeb Bush, the son of a president and brother to another, asked that his name be removed from consideration, citing the distance until the 2016 campaign will begin in earnest. He spoke at the conference on Friday.

Results of presidential election-year straw polls have proven more accurate indicators of the eventual Republican nominee than polls taken years in advance.

Straw poll winners who were never within striking distance of the nomination include Ron Paul, evangelical leader Gary Bauer and publishing scion Steve Forbes.

Most lawmakers, including Rubio, who addressed the crowd this week, encouraged activists to return to the conservative principles of the Republican Party.

But Paul struck a different tone in a speech on Thursday.

"The GOP of old has grown stale and moss-covered. I don't think we need to name any names, do we? Our party is encumbered by an inconsistent approach to freedom. The new GOP will need to embrace liberty in the economic and the personal sphere," Paul said.

The senator's views on foreign policy and civil liberties have earned rebukes from Republican Party fixtures like Arizona Senator John McCain, the 2008 Republican presidential nominee, who recently called Paul a "wacko bird."