Lemmings, small arctic rodents, undertake spectacular mass migrations at their peak of population growth, sometimes plunging over cliffs and drowning in the sea.

Chicago aldermen are politicians resembling lemmings, who cast spectacularly stupid votes at the behest of Mayor Rich Daley, heedlessly migrating toward doom and defeat in 2011.

The adjoining vote chart contains information concerning the 13 Northwest Side aldermen. Eleven supported Daley's $6.1 billion 2010 budget, three were unopposed in 2007, seven were reelected with more than 60 percent of the vote, eight have served four or more terms, and two were appointed recently to replace entrenched incumbents.

It would appear that only three -- Pat Levar (45th), Berny Stone (50th) and Scott Waguespack (32nd) -- are vulnerable in 2011, based on their narrow 2007 victories.

But wait! Look at that voter registration column. Not a single alderman's actual vote exceeded 28 percent of the ward's registered vote. In 2007 each pro-Daley alderman turned out his or her base vote, winning because the nonbase vote, which exceeded 70 percent, either backed the opponent or didn't bother to vote. The perception of invulnerability is wholly illusory.

In the 36th Ward the retired Bill Banks, who has been replaced by John Rice, won with 75.8 percent if the votes cast but got only 27.2 percent of his ward's registered vote. In the 41st Ward Brian Doherty (72.4 percent) got 26.5 percent of the registered vote. In the 38th Ward Tom Allen (unopposed) got 25.6 percent of the registered vote. In the 39th Ward Marge Laurino (79.2 percent) got 24 percent of the registered vote.

In the 45th Ward Levar (56.2 percent) got 22.7 percent of the registered vote. In the 50th Ward Stone (53.1 percent) got 22.4 percent of the registered vote. In the 40th Ward Pat O'Connor (unopposed) got 21.9 percent of the registered vote. In the 33rd Ward Dick Mell (unopposed) got 21.8 percent of the registered vote. In the 47th Ward Gene Schulter (78.5 percent) got 21 percent of the registered vote.

In the predominantly Hispanic wards it's worse. In the 35th Ward Rey Colon (62.3 percent) got 16 percent of the registered vote. In the 30th Ward Ariel Reboyras (70.2 percent) got 15.7 percent of the registered vote. In the 26th Ward the now-retired Billy Ocasio (who was replaced by Roberto Maldonado) got 14 percent of the registered vote.

But the "Anemic Award" goes to Scott Waguespack in the Wicker Park-Lakeview 32nd Ward. Waguespack upset flawed pro-Daley incumbent Ted Matlak, getting 50.8 percent of the vote in a runoff. His 4,179 votes constitute just 10.9 percent of the ward's registered voters.

So what's the relevance?

First, people need a reason to vote. Patronage has dwindled in the Northwest Side wards, but the local pro-Daley Democratic committeemen can still dispatch 30 to 60 workers into the precincts and can generate 75 to 100 votes per precinct. That "controlled vote" includes election judges, city, county and state workers and their families, friends and relatives of the candidate or precinct captain, and those repaying "favors."  Even so, since each city precinct contains approximately 500 registered votes, the "uncontrolled vote" is 300 to 400, or 60 to 80 percent.

Second, people need a credible candidate to vote for or against. In 2007 10 of the 13 area incumbents faced desultory opposition from unknown, underfunded candidates -- as did Daley in the mayoral race.

And third, people need a stake in the outcome. In 1983 and 1987, race motivated a huge turnout against Harold Washington. In 1979 rage over a lack of snow removal got voters motivated. In 1989, 1991 and 1995, when Daley faced black challengers, turnout was huge.

Turnout will spike in 2011. If Daley runs again, voter anger over tax increases, budget boosts and epidemic corruption will spur an anti-Daley vote, provided someone credible opposes him. If Daley retires, voter interest in picking his successor will be feverish.

My prediction: Daley will retire, and turnout in 2011 will be double that of 2007.

That means incumbent aldermen who are tied to Daley will have problems explaining their lemming-like record and expanding their base. It will be nearly impossible for them to garner more votes in an anti-incumbent environment, and aldermanic challengers, by making the race a referendum on the incumbent, can win simply by attracting a third of the registered vote.

In the 36th, 41st, 45th and 47th wards, 10,000 votes would be enough to unseat Rice, Doherty, Levar or Schulter. In the 38th, 39th, 40th and 50th wards, 8,000 votes would be enough to beat Allen, Laurino, O'Connor or Stone. In the remaining wards, just 5,000 votes would be enough to oust Mell, Colon, Waguespack, Reboyras or Maldonado.

The incumbents' greatest fear is multi-candidate opposition, with four or more foes pounding the alderman and developing a base. Historically, incumbents who fail to get 50 percent of the vote in the February nonpartisan primary usually lose the April runoff, since the anti-incumbent February majority backs the surviving challenger in the runoff.

Expect a plethora of candidates in every area ward in 2011. Candidates can begin circulating nominating petitions in September of 2010, and they must file for the election in December.

Here's an early preview of developing contests:

45th Ward: Levar has been diagnosed with prostate cancer, and he will soon begin treatment. "I'm definitely running again," he said. But if his health deteriorates, it may preclude a bid for a seventh term. Levar supported Daley's budget, and he has long been a Daley toady in the City Council. After 22 years, there definitely is "Levar Fatigue" in the ward.

In 2007 Levar ran 3,532 votes behind Daley, getting 7,380 votes, or 56.2 percent of the total cast, against less-than-formidable opposition. Turnout was 13,132. Levar's base has dwindled to under 7,000. If turnout in 2011 exceeds 16,000, he is doomed.

Possible candidates include 2007 loser and former Levar aide Terry Boyke, Forest Glen real estate agent Anna Klocek, former Portage Park Neighborhood Association vice president John Arena, Six Corners Association economic restructuring committee chairman Don Blair, Chicago police lieutenant John Garrido, who is seeking the Republican nomination for Cook County Board president, accountant Bruno Bellisimo and neighborhood activist Greg Sedlacek. More will file.

Rumors persist that Levar may resign in 2010 and arrange the appointment of his son, Pat Jr., as alderman. "I will not resign," Levar said. "I do not want the job," his son said. The more likely scenario, should ill health force Levar out of the 2011 race, would be enormous City Hall pressure on popular state Representative Joe Lyons (D-19) to run. On a scale of 1 to 10, Levar's reelection prospects are a 3.5.

41st Ward: It's easier to beat nobody than somebody, which is why everybody who wants to run for alderman fervently hopes that Doherty gets elected state senator in 2010. If so, he'd resign as alderman, creating a 2011 free-for-all.

Doherty, a Republican, was first elected to the City Council in 1991. With state Senator Jim DeLeo (D-10) retiring, Doherty is favored to win his Senate seat. However, Doherty insists, "If I lose (for senator), then I'm running for reelection." If Doherty seeks a sixth term in 2011, he would be favored, although tarnished by his November loss and occasional Daley support.

The front-running Democrat for DeLeo's job is attorney John Mulroe, an ally of 41st Ward Democratic Committeeman Mary O'Connor, who covets Doherty's job. That creates a curious contradiction in which a Mulroe loss benefits O'Connor, but a Mulroe win would damage O'Connor's 2011 prospects. Mulroe said he will not run for alderman if he loses.

Also interested are Chris Raguso of Edison Park, the acting commissioner of the city Department of Community Development, and Doherty's "community representative," Jim Del Medico.

The outlook: Doherty's organization will field somebody, but uncertainty reigns. A 2011 race without Doherty would draw a dozen candidates, but most will not surface until after Nov. 4. Absent Doherty, O'Connor is the leader, but there surely will be a runoff.

36th Ward: Rice, Banks' chief of staff, already has three foes: Nick Sposato, a city firefighter who got 24.2 percent of the vote in 2007, attorney Larry Andolino and city truck driver Bruce Randazzo. Rice was appointed by Daley, and he is another mayoral stooge. Look for a runoff.

26th Ward: Maldonado, a former county commissioner, has real problems. Ocasio took a state job, and he wanted Daley to appoint his wife as alderman. Maldonado, the ward's Democratic committeeman, backed a local clergyman who was later discovered to live outside the ward; he then blocked Ocasio by taking the post himself. The neighboring committeemen retaliated by rejecting Maldonado's choice for his county board seat. The ward is like Afghanistan, with hostile factions everywhere.

50th Ward: Stone, age 82, was barely reelected in 2007, and he was ousted as the Democratic committeeman by Ira Silverstein in 2008. Stone said he is running again in 2011. If he does, he loses.