Endeavor’s poaching of Robert Newman makes it official: Whether it is a star client or a top dealmaker, it’s open season in Hollywood.

Newman and another key ICM agent, Matt Solo, defected Jan. 3, and anyone who saw the moves as a nasty, post-holiday shock to the system haven’t been paying attention. The winter break is just the time for back-table conversations, a period when it’s only natural to examine the year that’s past and consider hopes for the future.

According to one veteran raider, when business slows down in December, agents, who spend the rest of the year putting out fires, suddenly stop and look at the big picture. “And artists are reflecting on the year past and the one coming.”

With everyone taking stock, what better time to move in and engineer a switch?

Agents are usually pried away by money, the promise of a partnership. Those things, plus the need for a change of scenery, helped Endeavor snare Newman after a 17-year run at ICM.

It usually costs an agency a lot to bring over someone from a rival firm, but the raiders think it’s worth it. The new agent brings over manpower, contacts and a great roster of clients — and, as a bonus, the star agent’s exit weakens his alma mater.

However, the real art form is piecemeal talent poaching. Agents and talent alike say the key lies in a twin effort: Stroking egos with one hand and stoking insecurity with the other.

Talent is especially vulnerable if they fit into at least one of the following categories:

  • They’ve just come off a flop and might wonder why their agents didn’t protect them better.

  • Their agency has had a setback, such as the loss of a key agent, etc.

  • They’re going through a divorce and are feeling fragile.

  • Their agency has signed an up-and-coming client who’s getting first crack at the better jobs, for more money.

  • They’re up for an award and the suitor can lament that the current agency isn’t doing enough to promote the client’s chances.

And for 2007, there’s a bonus opportunity to prey on insecurities.

“Studio heads are openly talking about a strike,” says another agent. “The business has contracted drastically; there are fewer assignments. If people aren’t panicked, they are certainly wondering where the next job is coming from and whether their agents are working hard enough for them. That makes them susceptible.”

With the wooing of a client away from a rival, most successful poaching campaigns begin long before the first covert meeting with the target. The genesis is in an agency signing meeting, where agents share intelligence about clients who might be unhappy, drawing up strategies of who to chase and where they are vulnerable.

While some agents says that poaching is a year-round pursuit, others say there are occasional “open seasons.” When one agency appears vulnerable, a scent of blood in the water urges every other percentery to begin circling agents and clients.

While most agents acknowledge a ravenous rivalry for clients, they say most successful poaches come from long courtships, abrupt misfortune or a combination of both.

Jay Roach left ICM for CAA last fall after Fox unplugged his comedy, “Used Guys,” at the last moment. Roach, per sources, was upset he’d spent nearly a year working for free — and the cancellation was fiscally painless for Fox, because he, Ben Stiller and Jim Carrey lacked pay-or-play deals that might have pressured the studio to go forward.

Roach was susceptible to the sell that CAA wouldn’t allow such a disappointment to happen. Later that year, CAA was unable to halt the implosion of the Focus film “A Little Game,” which was populated by agency clients Gabriele Muccino, Cameron Diaz and Jim Carrey, or “Halo,” a splashy package deal that CAA brokered for Microsoft.

But in courting and signing a new client, perception is often everything.

CAA poached Carrey and M. Night Shyamalan at vulnerable moments: Carrey, coming off “Fun With Dick and Jane,” planned to follow “Used Guys” with “Ripley’s Believe It or Not” — only to request a creative overhaul on “Ripley’s” that led Paramount to apply the brakes. And “Lady in the Water” was the biggest debacle of Shyamalan’s career.

An agent’s boilerplate pickup line is “Are you happy?” However, most courtships are more subtle.

The no-pressure approach begins with simple socializing, something made easy when agency’s clients populate big films (and give agents reason to hang around movie sets). An agency might slip a script to a potential client as a no-charge favor, one that might get talent to wonder why their own agent didn’t provide it. By the time a client is looking to leave, the rival is well positioned.

In Carrey’s case, CAA’s earlier poach of UTA agent Dan Aloni came in handy, as he repped several of Carrey’s favorite collaborators, Tom Shadyac and Michel Gondry.

Two recent Endeavor signings came in a similar fashion. Steve Zaillian had been without an agent for years. A slow courtship by Ari Emanuel got the agency Zaillian (“Schindler’s List”) days before the disastrous release of his last film, “All the King’s Men” — a moment when the writer-director might see the value of being protected by a big agency.

Endeavor’s recent poaching of Kate Hudson from CAA also had groundwork laid early. Poached by CAA right after her breakthrough in “Almost Famous,” Hudson was agented for several years by Patrick Whitesell. She remained at CAA when he left to join Endeavor several years ago. A hit-and-miss B.O. track record, a divorce and the fact that her mom, Goldie Hawn, is ensconced at Endeavor were factors in her decision to rejoin her old agent.

Sometimes an agency can benefit from not having a stockpile of clients competing for the same jobs. Michael Bay, convinced he wasn’t going to see certain scripts before top CAA directing clients, didn’t have that dilemma at WMA, which recently made a 10% first-dollar gross producing deal for his Platinum Dunes genre banner.

And in going to ICM, Halle Berry found a hardworking veteran in Toni Howard and a team of agents eager to show their devotion. ICM, after much film attrition, was also bolstered with the recent landing of “Dreamgirls” star Beyonce Knowles and her agent, Andrea Nelson Meigs.

The recent exits of Hudson, Knowles and Hugh Grant (who decided to go without an agent) punctured an aura of invincibility that grew as CAA spent the past two years luring clients from rivals while losing few of their own. While CAA might claim to have deliberately trimmed its ranks, the losses have emboldened rivals.

There are a variety of time-tested tactics: You need better costars; we rep them. Why aren’t you getting better material? You should be getting paid more! Why did that agency offer your dream role to its other client?

A popular aphrodisiac for well-paid TV showrunners is the prospect of feature-writing assignments. Successful film scribes might be asked why their agents haven’t lined up a directing debut.

That was a helpful tactic CAA used in courting screenwriter Tony Gilroy, who was unable to make the jump to direct his script “Michael Clayton” until CAA put him in a room with George Clooney.

An actor or director with a production company will always take an agency meeting to discuss projects. If that meeting includes delivery of a plum script his own agents didn’t provide — well, who can blame him if he decides it shows him what a new agency could do?

A variation of this approach is also useful for actors who believe they’re doing well. It’s one thing to slip an actor a killer screenplay — but you kick it up a notch by mentioning that his own agency chose to give it to a bigger star.

Says one big-money writer, “You’ll be working with a director who’ll say, ‘You should meet my agent.’ If the agent is any good, he’s read all your scripts and can talk about where your career should be going. It’s hard not to be impressed, particularly if you feel like your agent is traveling the path of least resistance and booking you into the same kind of film jobs over and over. You want the person responsible for your living to be willing to lay in front of traffic for you.”

Small wonder that agents are ripe for cardiac arrest and sleepless nights. Even in failure, clients will almost never blame themselves for futility, not when there’s an agent within easy reach who can be tossed under the bus.

One dealmaker recalls being fired by an actor client who was reeling after a flop. Even though the actor acknowledged his agents advised him to avoid the pic, he says that he had to look at himself every morning in the mirror, and he wasn’t going to blame that guy. And it had to be somebody’s fault.

While most talent isn’t that candid, agents are often undeservedly sacked.

When CAA pried loose Shyamalan from longtime UTA agents Jeremy Zimmer and Jim Berkus, most wondered how Shyamalan could point the finger at anyone but himself. Shyamalan not only wrote and directed “Lady in the Water,” he was a producer and cast himself as one of the film’s stars. Shyamalan also participated in a making-of book that chronicled the project’s rejection by ex-Disney production head Nina Jacobson, whose script criticisms proved prescient.

Non-raiding agents say they worry daily that fickleness and an increasingly difficult climate makes even longtime clients susceptible to agents’ courting calls.

“You can just tell by the language that your client is being hit on when your writer calls and asks, ‘Why am I not directing?’ or ‘Why didn’t I get such-and-such a job?’ ” says one well-established dealmaker. “It is never fun and it costs you sleep. But it is part of the game.”

One poaching agent says prospective clients are becoming more sophisticated about pickup lines. He points to the rules of courtship laid out in a recent episode of HBO’s “Entourage,” in which protag Vinnie Chase was a white-hot object of agency desire. Each agency whisked him into a conference room packed with eager tenpercenters — and each time, he was confronted with a PowerPoint demonstration that promised to brand him like Coca-Cola.

“That was done a lot two years ago,” says an agent. “That episode was something of a humorous but cautionary tale that agencies have to be more creative.”

One agent says prospective clients are also past getting star-struck by signing meetings attended by the agency’s heavy hitters.

“Artists are better off looking at the team of agents that is really going to be fighting for him, and decide whether he’s better off where he is or with this group of people. (The question is,) who’ll help him through the next five years of ups and downs,” he says. “Otherwise, that piece of talent will be right back where they started, listening to another volley of empty promises from a new group of agents.”

The unnamed screenwriter put it more succinctly: “You’ve got to remember that the signing meeting has little to do with how you’ll be represented. If you sign, you’re giving an agency two years of your career, so you’d better be sure. With a possible strike coming, there are maybe two or three jobs left for a writer, and possibly a long layoff after that. This is serious stuff.”