From February through June, hundreds of harbor seals sleep, mate, sleep, give birth, and then sleep some more on beaches like one at the center of the Monterey Bay national marine sanctuary, Hopkins Beach. Maybe you thought this was months ago — those were elephant seals, harbor seals' uglier cousins. The time is a delicate one for the harbor seals, and experts at the Marine Mammal Center encourage humans to give them plenty of room. This year, for the first time according to a report by KQED, the Sausalito-based center has received complaints about drone hobbyists flying their aircrafts near seals. That's added a new layer of concern to the stressful time period.

"Drones are totally foreign to these animals," Laura Chapman, a rescue coordinator with the Marine Mammal Center, tells KQED Science. "They make a sound that they [the animals] don’t expect."

It's not just interrupted mating sessions that experts want to avoid — although presumably that, too. Mostly, pups need to be safely kept with their mothers. In the past decade, the center has handled 140 cases in which humans caused harm to seals or sea lions, KQED reports. Disturbances can cause seals to abandon their pups — or people can separate them by "rescuing" pups they see, as has too often occurred.

Humans are required by the federal Marine Mammal Protection Act to give the creatures 150 feet of space, and those flying drones should heed that rule too, Chapman seems to say. “What we want people to be aware of is that if an animal is looking at you, if they’re looking at the drone, that animal is being harassed.”

A Hopkins Beach docent, Thom Akeman, tells KQED he's had to shoo away drone pilots. “About half the time they’re very cooperative,” says Akeman. “Other times they’re very belligerent because they think they have a right to fly anywhere.”

Not exactly: Federal Aviation Administration rules ban drones within five miles of airports, and there's one 3.5 nautical miles from the Monterey Bay Aquariums harbor seal rookery, for example. If you're headed there, leave the drone at home. The marine sanctuary, for its part, is monitoring drone use.

Related: Where To Watch Elephant Seals Doing Their Annual Mating And Birthing Thing Along The NorCal And Central Coast