A quick tour of Mary Ellen Glover's Manassas home tells you everything you need to know about the 52-year-old insurance agent's true passion: rabbits.

The place is bursting with bunnies. Porcelain bunny lamps sit on tables adorned with bunny knickknacks. Bunny-decorated dishware is stacked in the kitchen. A floor-to-ceiling mural in the dining room depicts three fluffy bunnies.

But there are plenty of real ones, too. In all, 33 rabbits live at the Glover home -- most of them unwanted pets awaiting adoption.

Upstairs, a dozen bunnies snuggle in hutches, in rooms closed off by colorful gates painted with bunnies. Downstairs, two dozen rabbits doze or hop around roomy cages stacked in an addition that Glover and her husband, Al, built especially for them.

"This is a place where you can tell that bunnies are loved," said Glover, a cheerful woman wearing pewter rabbit earrings and a smock decorated with paintings of the floppy-eared animals.

Glover heads Bunny Lu Adoptions, a Prince William County animal rescue group that takes in homeless and unwanted bunnies and then places them with people who truly want them.

She's part of a passionate network of small, grass-roots organizations throughout Northern Virginia that are pledged to try to save the flood of unwanted pets pouring out of area homes.

At this time of the year, the flood becomes a torrent. More pets land at shelters and with animal rescue groups in the summer than at any other time of the year, according to the organizations.

Summer is a time when many people move, and a new landlord may not be as enthusiastic about that screeching cockatiel as the cockatiel's owner.

Unspayed animals, particularly cats, also tend to have litters in the summer, and many surprised pet owners turn the newborns over to shelters and rescue groups. Some people go on vacation and decide it's cheaper to give up the family pet than pay for a kennel.

"I think their minds go on vacation," said Faith Hood, who runs a ferret rescue group out of her Falls Church home. "It's just amazing that these people don't think."

The deluge of unwanted pets has left many of the rescue groups -- which, unlike most area animal shelters, generally do not euthanize animals -- struggling to cope.

One Fairfax cat rescue group, 4Paws Rescue Team, finds that the number of cats in its volunteer "foster" homes, which keep the pets until permanent homes can be found, doubles in summer to 175 from its wintertime total, 4Paws President Barbara Lipson said.

In fact, the overabundance of homeless felines has forced 4Paws to place a temporary moratorium on accepting them, she said last week.

"We have been turning away a lot of cats that we can't help because we don't have foster [homes] and we don't have the financial resources," Lipson said.

Most animal rescue groups are small and, like the pets they help, come in a variety of types, shapes and sizes. Most focus on a particular breed and depend on volunteer foster homes. For many, animal foster care is a labor of love.

Hood, for example, cares for as many as 25 homeless ferrets in her basement apartment on behalf of the group she heads, FerretsR#1.

The roomy cages and exercise areas for the perky pets have taken over one room of Hood's apartment, and she has a part-time job, in addition to her full-time job, just to help cover the $10,000 annual cost of carrying for the ferrets awaiting adoption.

In the six years since Ferrets R#1 was founded, it has found homes for about 600 ferrets.

"That's what makes it all worthwhile," Hood said.

In Loudoun County, Cheryl Rogers and her mother, Pat Rogers, run the Equine Rescue League on a 66-acre Leesburg farm leased from the county. The group not only takes in unwanted and abused horses -- about 40 are available for adoption -- but also serves as a temporary home for a variety of barn cats, a few dogs and even, at one time, a couple of unwanted potbellied pigs.

"We've dedicated our lives to this," Cheryl Rogers said.

According to pet rescue groups and animal shelters, the major reason for the vast surplus of unwanted pets is that too many people impulsively purchase cute animals at pet stores without thinking through the consequences of caring for the animal for years.

"It makes me crazy," said Jennifer Carpousis, of Fairfax, who runs the Great Pyrenees Rescue group, which is seeking homes for about 80 of the dogs. She said they start out as "cute, puffy babies" but then grow into giant, bearlike dogs entirely unsuited to cramped homes.

Even the demands of bird ownership can catch owners unawares. Many bird breeds survive for decades and may outlive their owners. Large breeds of parrots have a life span of more than 50 years, said Ann Brooks, an Arlington federal worker who runs Phoenix Landing, a Northern Virginia bird rescue group.

"This is no impulsive-decision kind of companion," Brooks said.

Because careless pet owners often dump pets when they're sick, old or injured, rescue groups' veterinary bills can be astronomical. The Feline Foundation, a Fairfax group that places about 500 cats a year in adoptive or foster homes, spends $100,000 a year on veterinary care, said Laura Goodman, foster coordinator for the group. To prevent the pets they place from rebounding to their care, most rescue groups and shelters require prospective owners to fill out extensive applications and consent to a home visit by a volunteer.

The Feline Foundation talks to a potential pet owner's veterinarian, verifies the number and types of other animals in the home, and queries applicants closely about their lifestyles. If a would-be cat owner travels a lot, the group may suggest an older cat that is content to play by itself, not a cat that needs a lot of interaction with humans.

Phoenix Landing requires potential bird adopters to attend the informational seminars it holds to educate the public on the demands of bird ownership.

"We make sure that people understand all that and are prepared for it," Brooks said. "Otherwise, the bird is just going to bounce again and again and again and get worse each time."

Pet rescue groups also don't hesitate to demand the return of a pet if they find out it is being mistreated in its new home.

Hood once reclaimed a ferret she had placed after getting an anonymous call that the animal was being kept outdoors in a tiny cage that didn't allow it to turn around. "I snuck over and stole him," she said. The pet owner never complained.

To find local animal rescue groups, go to www.petfinder.org. You can search by animal breed and by other categories.

Charley, center, and Hazel, two rabbits in need of a home, chow down next to a rabbit toy in Mary Ellen Glover's home in Manassas.Mary Ellen Glover, holding Merlin, top, has turned her house into a rabbit-themed rescue home, even building a new room, left, to hold more animals.