A rash of recent coyote attacks has created a stir among dog walkers at the Lynn Woods Reservation.

“Since the notices went up, I’ve been a little bit nervous about coming here,’’ admitted Stacy Grillo, 35, of Saugus, who was getting ready to walk Buddy, her bichon frise, last Saturday morning.

“We kept her on a leash and didn’t go too far in,” said Susana Sinclair, 38, of Salem, walking a mixed breed named Palomita.

The advice to keep pets on a leash is the message being sent in large black letters on the notice posted at reservation entrances, after seven reports of coyotes attacking dogs inside or near the area in May.

Ranger Dan Small has been at the reservation for 13 years, employed by the Lynn Water Sewer Commission. He knows of five coyotes that divide the 3½ square miles of the reservation, a pair that lives to the north, a pair that lives to the south, and one that makes its den in the reservation near Parkland Avenue and spends some time in nearby neighborhoods. Small is not sure if that one has a mate. There have been attacks on animals in the past, but never this many in such a short period of time.

Coyotes are territorial animals, and Small noted that the five attacks on reservation grounds took place at different times of the day, within 100 yards of one another, near a landmark called Fox Rock, where surrounding habitat makes it a likely spot for a coyote den. He theorized that they may have been defending pups, in a year when the food supply is lower than usual.

“They might be under extra stress because there’s not a lot of food,’’ he said. “They live a lean existence anyhow, and this year there are not a lot of rodents” and other small mammals. Populations in nature are often cyclical, and the past two years have been thin for acorns. “When you knock something out on the bottom of the food chain, it trickles up the ladder,’’ Small said.

Another attack he heard about was in the Thistle Street neighborhood on the edge of the reservation, Small said, and the seventh was at the Gannon golf course, which abuts the reservation.

Dog walkers have continued to use the reservation, and not all of them are nervous. Marblehead’s Alison Howe, 38, walked Jada, her half-rottweiler, half-black lab, and at one point let the dog off the leash.

“She stays pretty much by my side and doesn't get too far away,’’ said Howe, who said she wouldn’t let the news deter her from spending time in the woods. “We all have to get along,’’ she said. “It’s their area, too. Maybe we have to be a little more vigilant. I’ve been camping and hiking all my life. The last time we went I heard coyotes; it's just part of nature.’’

In the case of two large dogs that required medical treatment, the coyote or coyotes “got a hold of their bellies and grabbed the skin and tore the stomach open,’’ Small said. “If the dogs had been a little farther away or if it had been a smaller dog, it would probably not have gone so well.’’

Small was responsible for posting the notices at reservation entrances. They read: Keep your dogs leashed at all times while in the Lynn Woods Reservation. Unleashed pets are in danger of injury or death as a result of contact with coyote and other wildlife.’’

Authorities also recommend that humans reinforce any natural fear of humans that coyotes may have by making noise and shouting.

“You can yell, or bang a stick against a tree’’ to make noise, Small said. “Act like a caveman and they’ll leave.’’

This is not the only time coyotes have been in the news this year.

In January, Methuen police shot and killed a coyote that had killed a pet chihuahua a few days earlier. In February, Wellesley police issued a coyote alert after the animals attacked two dogs, killing one of them.

Tom O’Shea, assistant director of wildlife for the Massachusetts Division of Fisheries and Wildlife, said that aggression toward a dog is typical coyote behavior.

“If a coyote demonstrates indifference or boldness [to people], that one you want to notify officials about right away,’’ O’Shea said. “Even worse is if it follows you or approaches a dog on a leash — approaching and showing outright aggression. We have had them, and those coyotes have been removed.’’

O’Shea preceded Small as ranger in the Lynn Woods in the 1990s, when the coyotes first appeared and were a novelty.

Since first appearing in the state in the 1950s, the population has grown. Officials now estimate there are 10,000 coyotes in Massachusetts.

“They’re in every city and town in the state, and the vast majority fear people and are elusive and stay away,’’ he said. “We want people to recognize the behavior of the coyote that could become a public safety threat.’’ While the word had definitely gotten out to many of the dog walkers — who had their dogs on leashes and were avoiding Fox Rock — it did not reach all of them.

On Saturday, Lynn’s Sylvia Ortiz, 24, was getting ready to walk Spikey, her mini poodle-bichon frise cross-breed.

“I haven’t heard anything,’’ she said. “Thanks for letting me know. He doesn’t like to be on the leash, but now that you’ve told me, I'm definitely going to keep him on the leash.’’