He and fellow mounted patrol officer Kevin Napoleon barked at the man to get off his bike, as the horse-hitter tried to pedal away in the grass at Ala Moana Beach Park. McKinney leaned over in his saddle, grabbed the man's shoulder and pulled him off his bicycle.

"The (expletive) horse bit my hand," said the man.

A quick inspection by the officers squashed that claim, and the man was arrested for assault on a deputized police animal. The officers learned when he was booked that their culprit was carrying a small stash — less than a gram — of crystal methamphetamine.

"That's a couple of firsts," said Napoleon, a member of HPD's mounted unit since it started up two years ago. "That's the first time anyone has hit a horse and the first time anybody tried to run."

Tuesday's arrest was one of seven that officers on horseback have racked up this month. In the two years since the program became a part of HPD's Specialized Services Bureau, they've averaged between five and 10 arrests per month and written between 20 and 50 traffic citations.

The mounted unit, comprising a sergeant, four officers (one of whom, Christopher Rabago, is away on military active duty) and nine quarterhorses, patrols high-crime areas, maintains crowd control and helps search rough terrain when people are reported missing.

"We like the reaction we get: 'I can't believe I'm getting pulled over by a horse,' " said Napoleon. "We may be here (in Ala Moana Beach Park) today, but tomorrow we could be in Chinatown, or out in Kailua, Kane'ohe, Wai'anae."

The mounted cops are involved with community outreach programs with local charities and schools. They'll let just about any kid pet one of their horses, if the youngster's polite enough to ask.

"We have a hard enough time connecting with the community. (On horseback) it is a nice way to get in touch with the community," said Officer Sharon Walden, who rides Justice, a horse she bought with her own money. "I've never had anyone want to come up and pet my police car."

Sgt. Deborah Wilson, the unit commander, who has been with the group since its inception in 1999, said there are several advantages to patrolling high-crime areas on horseback.

Horse-mounted officers have a distinct visual advantage over officers in patrol cars. On horseback, an officer can see over obstacles that might block the sight of an officer in a car. Also, horse-mounted officers can approach suspicious situations quietly in all kinds of terrain, from mountainsides to rocky beaches.

"We can go just about anywhere — water, ditches, over walls," said McKinney, who regards the horse as "the original all-terrain vehicle."

Wilson said just the presence of officers on horseback makes the public feel safe and is a big deterrent to potential criminals.

"Patrol (officers) are slaves to the radio. They get a call; they are in and out; and crooks who are sitting around watching can see the car get called off," said Walden. "With horses, they (the criminals) don't know when we're there or not. We can pop out of the woods or roll down the beach."

Gary Hailstone, a part-time Honolulu resident who has a home in San Diego, said he's familiar with mounted patrols. Some of the larger California cities have similar units, and he's happy to see one being used on O'ahu.

"If you're up on a horse you have more of an area where you can look than you can from the ground," he said.

There are some disadvantages to saddling up.

Tending to the animals is a seven-days-a-week job, and the officers begin and end their days feeding and bathing the animals and picking up after them. The stables are in Waimanalo. That means the officers' days begin and end out there, oftentimes shoveling hay, regardless of where they're assigned to patrol.

Training the animals is an ongoing effort. The officers are continually making their mounts feel more comfortable with police work and with having armed officers riding on their backs. Wilson and the others admit that the animals become a big part of their lives.

Then there's the excrement factor. All mounted unit officers have to pick up after their horse partners, no matter where or when they decide to use the bathroom. One saddle bag on each horse is reserved for droppings, and the officers carry pooper-scoopers.

"The poop thing slows you down some," McKinney said.

The unit in 1999 was set up by Wilson, Walden and eight other officers who wanted to revive HPD's first mounted unit since it had been disbanded in the early 1900s. Nationwide, there are more than 2,000 mounted units in metropolitan police departments.

At first, the Honolulu officers had to buy their own horses and pay all expenses associated with caring for them.

"I must have written off $15,000 that first year," Walden said.

Mounted shifts were undertaken only after the officers had completed patrol commitments, meaning most worked seven days a week.

The unit shrank from 10 officers to two in a matter of six months.

"By then we had put so much into it, that we kept going and eventually proposed it to (then-Chief Lee Donohue)," said Wilson.

Luckily for the unit, Donohue responded in 2002, approving the purchase of six horses, and deputizing them as soon as they had completed the necessary 90-day training phase. Along with buying the horses, Donohue OK'd the purchase of trailers, and approved rent for nine stalls and a horse track. Each quarterhorse costs between $3,000 and $5,000.

Before the horses were bought, each was put through a 90-day evaluation process to ensure that their temperaments were right for police work. Wilson made sure that the horses could be controlled and had calm demeanors to avoid instances where they might get scared and bolt into traffic.

Today, the unit is inexpensive to run, Wilson said. It costs less than $56,172. Still, Wilson and her officers are forced to work long, hot hours, with few days off.

"We work seven days a week. I've never been so sore and so tired," said Wilson.

"But I've never had this much fun being a cop."