Just before 10 on most weekday mornings, a handful of young children swing or slide at Johnson Park on Hawthorne Avenue in Palo Alto.
Then out of nowhere, a dozen small tots -- like ducklings behind their mother -- trot into the park. It's clear they are from some sort of preschool, but it's not obvious where, since there are no advertised ones nearby.
In fact, the school, known as Periwinkle, is in a deep brown Craftsman house on Byron Street four blocks away. There is no official sign out front saying that it's a school, only telltale signs, like an easel, bright colors and a whiteboard on the porch with a schedule.
Founder PJ Lents said the main advantage of her 12-child school is the ability to spend more time on activities. Formerly a kindergarten teacher who taught classes of 20, Lents is now able to split her class of 12 and have one half work with one teacher and one with another.
"We make faster progress, which allows us to have really rich learning opportunities," she said.
Started by a group of Bing Nursery School parents in 2005, Periwinkle focuses on "young 5s" -- children whose birthdays place them at the younger end of their peer group. Lents and her family live in the upstairs part of the house.
More expensive than traditional preschools, several other "pocket" preschools, with enrollments under 15 children, have popped up in the Menlo Park-Palo Alto area. Most do not advertise, only one has a website, and tracking down a phone number or email address may involve a chance post on the ratings site Yelp.com. Yet these schools have no trouble filling up, as word of mouth among parents creates long waiting lists.
They seem to appeal to people looking for something tailor-made for their kids -- and to those uncomfortable with sending their children to kindergarten before they are ready, a growing trend.
Stephanie Agnew, parent education coordinator at Parents Place in Palo Alto and San Mateo, expects the demand for alternative programs for younger 5-year-olds will increase as the required birth date for kindergarten entry gets later. Therefore, she said, the need for these smaller preschool programs will likely increase.
Many parents see larger schools as attractive because they have more resources. While those benefits help some children, Agnew said, a shy, slower-to-warm child can increase in confidence at a smaller school.
"The biggest advantage is that the children get individual attention, and it's less over-stimulating," she said.
Debbie Baker, a former kindergarten teacher, started her small preschool -- Circle of Friends on Alameda de las Pulgas in Menlo Park -- to meet children's developmental needs and to keep her in the classroom.
"Could it grow beyond this? Yes, but then I'd be sitting in an office," Baker said, while showing a visitor her cheerful classroom with a painted sky and skylights on the ceiling. "It would be hard to keep (my) philosophy going in more than one classroom. This way, I can live the dream."
Baker tore down her old detached garage, received a license to run a home day care program from the state of California, and built a light, airy and compact preschool classroom where the garage used to be.
Behind tall, double wooden gates, the school is invisible from the street and there is no sign.
In less than 1,000 square feet, there is a rug area for miniature building projects, and a dress-up area tucked under a set of stairs leads to a cozy loft book nook. Art project and puzzle areas await little hands, and the flexible space allows children to move from activity to activity. Two adults oversee 12 children. Some children come daily while others only attend two days a week.
Circle of Friends enrolls 3- and 4-year-olds in a class together for very specific reasons.
The mixed age group "allows the children to mentor each other," Baker said. "When younger children learn skills, they usually do it imitating older children or adults. The older child scaffolds the younger child's skills."
The smaller class size allows for a slightly quieter room and provides an opportunity for children to learn problem solving. Baker is able to hear nearly everything going on in the room and can intervene immediately.
Baker's school is far from a simple home day care program, she said. She has stringent standards for herself and the other teachers. She also conducts twice-yearly developmental assessments of each child to track their progress.
Baker said another advantage of the diminutive size of her school is she gets to know families intimately and often enrolls a succession of siblings from the same family.
Avery Olesen, who teaches part time at Ohlone Elementary School in Palo Alto, sent all four of her daughters to Circle of Friends.
"The smaller size, at this age, enables each child to have a voice," Olesen said. "The teachers really seem to know each child well and work to develop their strengths and support their learning needs."
Olesen's youngest daughter just started kindergarten this fall.
"My girls all did fine socially and academically. They seemed to adjust well to kindergarten. They have a healthy appreciation for learning and seem very inquisitive," she said.
That innate curiosity is also fostered at another small preschool, aptly named Our School.
Located in the Willows neighborhood in Menlo Park, it is well known among both Willows and Suburban Park parents, but nearly unheard of in west Menlo Park. The school has no website, is unlisted in the telephone book, and one nearly has to stumble across a telephone number or email address to find it.
Willows parent Jodi Robbins, on the other hand, had no trouble finding Our School and put her child on the waiting list at 18 months.
Robbins also enthuses about the school's way of teaching through experience. Most afternoons, the children are taken on an outing to get popsicles, hear a symphony, or go to a local bagel shop where each child is encouraged to order his or her own.
"Regular preschools don't focus on the things that her preschool does," Robbins said. And, kindergarten teachers can tell, she said. Her daughter's teacher said she can recognize those who've gone to Our School because they can hold their attention better and they form tight social bonds with fellow preschoolers that carry over to elementary school.
A Suburban Park mother said she chose Our School for her second daughter knowing that, with a fall birthday, she'd be starting kindergarten at almost 6.
The school, said this mother, who is a former third-grade teacher, is "experience rich."
The children learn about spiders, look for spider webs, or talk about chameleons and blow toy whistles to practice making chameleon calls.
Her daughter, she said, "skips" to school every day.
"It gets her out of bed and she's thrilled."