Equestrians on the beach at Border Field State Park, 1.5 miles north of the border by the Tijuana River mouth.

Border Patrol agents in Imperial Beach are seeing an upsurge in bicycles and horses being used to smuggle humans across, Border Patrol spokesman Tim Hamill confirmed Friday. In the past few weeks, Border Patrol agents made arrests after noticing, for example, that two horses ridden into the parklands next to the border by two riders came back out with three riders. The men were taken into custody and the horses were seized. In another instance, one of two equestrians hanging around the border fence was poised to switch seats with an identically dressed illegal border crosser.

A lone rider about 100' north of Mexico at the base of Bunker Hill in Border Field State Park. Border Patrol keeping an eye on her from the mesa.

One such incident was in Smugglers Gulch — where the couple was preparing to switch places. The other was above the gulch, on top of Spooners Mesa. Smugglers Gulch is the defoliated canyon right on the border (just north of Mexico’s Hwy 1- Libre from Tijuana to Playas), about 1.5 miles east of the ocean. "Smugglers are going to try anything and everything to get people across for money," Hamill said. "It's a method we've seen before, like most other methods. Which ones they're trying is cyclical."

As a courtesy, the Border Patrol notified local equestrians that they may fall under heightened scrutiny, Hamill confirmed.

Vickie Strauss, president of the Tijuana River Valley Equestrian Association posted messages to the valley's members, giving them a heads-up that they may come under increased scrutiny when they ride near the border.

"Most of our people wouldn't have known about this and would wonder why we're being approached," she said. "It's really helpful that they told us so we can get the word out."

It isn't the first time that human smugglers have tried using horses, Hamill said. But it has been a while — horses are hard to come by, and you wouldn't risk having your own horses seized, Strauss said.

Human smugglers collect at least $4,000 and up to $6,000 for each person they successfully smuggle across by land. "Greed drives them and they just keep trying," he said.