BY TYLER BRIDGES

Newly freed former presidential candidate Ingrid Betancourt said she began to realize a year ago that Colombia's largest guerrilla group was having troubles when supplies could no longer easily reach the jungle camp where she and other kidnapped hostages were held.

Hours after being freed in a daring rescue Wednesday, Betancourt said that clothes, rubber boots and food stopped arriving as needed.

''Our diet became very thin,'' Betancourt said.

Betancourt and 10 former guerrillas interviewed by The Miami Herald confirm what experts have been saying: The Revolutionary Armed Forces of Colombia have been suffering devastating blows that have left the guerrillas on the ropes.

The rescue of Betancourt, three U.S. military contractors, and 11 Colombian policemen and soldiers was the biggest blow yet.

Even before that, guerrillas had been surrendering in droves, and they rarely have been able to mount attacks anymore.

''Kerli,'' a nom de guerre, had been a member of the FARC guerrillas for six years and was hungry and weary of the Colombian army's constant harassment.

''Many guerrillas are deserting,'' Kerli, who did not want to be identified for fear of reprisals by the FARC, said by telephone from the jungle military outpost where she is being held. ``The situation is bleak, especially now that the old man is dead.''

The old man was Manuel Marulanda, the alias for Pedro Antonio Marin, the long-time head of the FARC, who died on March 26, apparently of natural causes.

Analysts say the insurgency has as few as 8,000 members today. Three of the seven members of the FARC secretariat -- including Marulanda -- died in March under different circumstances.

As recently as 2000, the group had about 16,900 members.

The 10 former guerrillas interviewed by The Miami Herald expect, however, that the FARC will continue to exist in some form, perhaps under a different name, because the rural poverty will continue to serve as a recruiting tool for those in isolated areas not yet subject to the military's attention. Some field commanders will continue to operate in areas with little government presence thanks to the profits from trafficking cocaine.

About 60 percent of Colombians live in poverty, meaning they subsist on $2 a day or less. Colombia is the world's biggest source of cocaine. (Guerrillas receive a nominal income in the FARC, along with meals and clothing.)

What happens to the FARC has widespread implications. The Colombian government's decision to cross a mile into Ecuador on March 1 to kill rebel leader Raúl Reyes sparked a diplomatic crisis that pitted Ecuador and Venezuela against Colombia. Tensions have not fully cooled.

HEAT GOT TURNED UP

Washington is spending some $600 million a year under Plan Colombia to help the Colombian government attack the FARC and counter drug-trafficking.

The four former guerrillas sitting around a table at a government building in downtown Bogotá can attest to the program's success. They no longer want to overthrow Colombia's democratically elected government. The former guerrillas agreed to be interviewed on the condition that aliases be used.

''It was a good life before,'' said ''Henry,'' 28. He got enough to eat, had the chance to study in FARC-run jungle schools -- Henry had left school after 5th grade -- and only occasionally engaged in firefights with government troops.

But when Alvaro Uribe became president in 2002, he fulfilled a campaign pledge to dramatically up the ante. Instead of mostly playing a blind eye to the FARC, the military beefed up its ranks -- in part with the U.S. aid -- and began to hunt the guerrillas in their jungle bases and mountain hide-outs.

By 2008, Henry's unit in the state of Antioquia had to march at night to evade the army and often ate nothing more than rice and beans once a day. The unit's ranks declined from about 2,000 to 600.

Henry longed to be reunited with his 5-year-old son.

''Being a guerrilla had become difficult,'' Henry said. ``The army was closing in on us.''

''Brian'' remembered the guerrillas' heyday a few years ago, when drug profits and the absence of the military allowed them to buy cars, motorcycles, computers and small ranches in Vichada state.

Military troops killed Brian's commander last year, a popular guerrilla leader known as ``El Negro Acasio.''

Afterward, morale plummeted, and communicating with other units became increasingly difficult due to the military's ability to intercept cellphone calls.

''We were getting squeezed,'' Brian said when asked why he surrendered.

FLOW OF DESERTERS

Col. Carlos Rojas, who commands one of the mobile brigades combating the FARC in the state of Meta, in central Colombia, said the guerrillas who surrendered a few years ago had been among the FARC ranks for only a year or two.

''Now they had been in five, eight, 10 years,'' Rojas said. ``The FARC is collapsing from within.''

''Walter'' deserted with his 20-year-old guerrilla girlfriend three months ago.

Walter had been a guerrilla for 16 years and held a mid-level post in the state of Caquetá.

''Five or six years ago, the army's operations were maybe every eight to 12 months,'' Walter said. ``Now it's every day, from above (airplanes and helicopters), below and all sides. A lot of informers help the government now. With cell phones, someone can see you pass by, call it in and you can then be attacked. We used to get 50 to 60 new recruits every month. There were no new recruits this year.''

For ''Michín,'' the decisive factor was the anti-FARC march on Feb. 4 that drew millions of Colombians throughout the country.

Michín began telling his girlfriend that they ought to defect, that the FARC had no popular support anymore.

When she finally agreed to do so in May, it was a public-relations coup for the government. Her name was ''Karina,'' and she had been the FARC's senior female commander, legendary for her fearlessness. Karina remains jailed.

''I want to study, work and be a good citizen,'' said Michín, 25, who didn't complete first grade but learned to read and write within the FARC. ``I don't want to fight any more.''

The government provides safe houses for those who defect, along with meager monthly stipends, retraining and education classes.

THE NEW LEADERSHIP

Alfonso Cano, a bearded former university student, is Marulanda's replacement. Analysts expect him to place more emphasis on instilling Marxist revolutionary ideas but say they see no major division between him and the FARC's hard-line military commander, known as "Mono Jojoy.''

Cano, however, will have to work to prove himself as a worthy successor to the guerrillas' rank-and-file.

''Marulanda was considered an icon,'' said ''Leonidas,'' a 43-year-old guerrilla who surrendered in Antioquia. ``It was like your father dying. He is irreplaceable.''

Still, ''John,'' a 19-year-old former guerrilla, said he doesn't expect the FARC to disappear.

''People are hungry in the countryside,'' John said. ``The FARC offers food and opportunities.''