With an increasing number of vulnerable seats to defend, National Republican Congressional Committee Chairman Tom Reynolds (N.Y.) gave his colleagues a stern warning Wednesday not to take electoral success in November for granted.

Two days after Rep. Jack Quinn’s (R) surprise retirement announcement put Reynolds’ neighboring district immediately into play, the NRCC chief used a GOP Conference gathering at the Capitol Hill Club to stress the importance of keeping further retirements to a minimum, especially in tough seats.

“It was a very strong message,” said a House GOP leadership aide. “A ‘wake-up call’ is the best way to put it.”

In recent months, Reps. Jennifer Dunn (Wash.) and Billy Tauzin (La.), both of whom represent swing districts, have also announced that they will be vacating their seats. Those moves, coupled with the retirements of Reps. Doug Bereuter (Neb.), Scott McInnis (Colo.) and, to a lesser extent, Amo Houghton (N.Y.), will force the GOP to expend valuable resources defending its territory.

Reynolds and his fellow Republican leaders were caught off-guard by Quinn’s decision, and the chairman emphasized Wednesday that Members who are considering retirement need to keep the NRCC in the loop. “He said he can’t just have these things sprung on him,” said a Republican aide who was present at the meeting.

Reynolds also said that those Members who have chosen to retire should use their leftover campaign funds to help the party. Departing lawmakers can help ease the burden of holding their seats by giving money to the NRCC and to vulnerable GOP incumbents.

As of March 31, Quinn, Dunn and Tauzin had just under $1 million apiece in the bank.

Even though Texas redistricting could well result in a net pickup of several seats for the GOP, Reynolds warned his colleagues not to let their good fortune in the Lone Star State diminish their vigilance in the rest of the country, especially since the races in Texas will require infusions of cash that could be used elsewhere.

While Reynolds’ message Wednesday was seen as more alarmist than his usual campaign updates, Members said his concern was understandable given the circumstances.

“Put yourself in Reynolds’ shoes,” said a senior GOP lawmaker. “He’s got to defend all these seats.”