Much has been written this cycle about the dwindling number of Blue Dog Democrats in the House. The group’s membership bore the brunt of the Democrats’ 2010 shellacking, and so far this Congress seven Blue Dogs have announced they won’t be back or are already gone — four are retiring, one is running for Senate and ex-Reps. Gabrielle Giffords (Ariz.) and Jane Harman (Calif.) resigned. Three of the four retiring are pictured above.

Rep. Heath Shuler (N.C.) became the latest Blue Dog to head for the exit Thursday, when he announced that after recently reflecting on his political career, he had decided he doesn’t want to return to Congress. “I feel very confident there’s going to be 20 others that take our place next year,” he told Roll Call’s Jessica Brady and Daniel Newhauser shortly after releasing his news Thursday.

But some of his colleagues sounded a little less confident when they began reacting to the move. “Oh man, that’s a crushing blow to the institution, and it’s tough for the Blue Dogs,” said Rep. Kurt Schrader (Ore.), a Blue Dog who had not yet heard about Shuler’s decision.

Looking at the list of remaining Blue Dogs, it becomes difficult to see how their numbers won’t shrink in the next Congress. Reps. Jason Altmire (Pa.), John Barrow (Ga.), Leonard Boswell (Iowa), Jim Matheson (Utah) and Mike McIntyre (N.C.) all face more difficult paths to re-election because of redistricting. Lines aren’t complete in Minnesota yet, but Rep. Collin Peterson (D) is another retirement possibility. Rep. Mike Michaud (Maine) might have a competitive race, but, according to his initial survey, he starts out in a solid position.

Brady and Newhauser report:

Democratic Congressional Campaign Committee Chairman Steve Israel, a one-time Blue Dog member, denied that the party’s goal of winning back the majority is any harder with Shuler and other fiscally conservative Democrats opting to leave Congress. “When we laid out our strategic plan to win 25 seats, we took into consideration the hill would be a little higher in places like North Carolina for us and much higher in areas like Illinois, California and elsewhere” for Republicans, Israel said.

In other news Thursday, the Senate passed the STOCK Act after a surprisingly open amendment process forced lawmakers to take stands on a series of ethical restrictions and earmarks, Steven T. Dennis reports. The House is expected to take up the measure as soon as next week.