This Swainson's hawk, seen in 2009, is believed to have returned to a nest in Moose Jaw, Sask., where it has resumed aerial assaults on Canada Post letter carriers. (CBC)

Home mail delivery in Moose Jaw, Sask., is being disrupted — again — following renewed aerial assaults on letter carriers by protective hawks that have taken up residence in a neighbourhood.

Residents of four city blocks were notified Friday that service was being suspended due to safety concerns.

People were told they can pick up their mail in a downtown Moose Jaw postal outlet.

"This [Swainson's] hawk has got a nest way up in this pine tree," Sophia Randall explained to CBC News Thursday. "And he's flying around all day and squawking."

Sophia Randall says she has seen her letter carrier wearing a helmet to protect himself from a swooping Swainson's hawk. (CBC)

Residents believe there is a male and female in the nest and that they had one fledgling earlier in the summer.

Randall said she has seen the birds swooping down and is convinced the letter carrier is a frequent target.

"They would just swoop on him all the time as he went from house to house," she said.

Randall noted that for a time the letter carrier took to wearing a helmet.

Another resident observed Canada Post officials trying to outwit the birds by sending two letter carriers to the area.

The hawks are nesting in a tree on Marie Fish's property. She is not concerned about the birds and does not have a problem with having their nest removed, so long as the birds are not harmed. (CBC)

"They tried to confuse the hawks by both going down the same side of the street," Pamela Peterson, a resident of Henry Street, told CBC News. "But it didn't confuse the hawks."

The hawks' nest is in a large evergreen on Marie Fish's property and she confirmed the birds have been a problem in the past.

In 2009 Canada Post suspended home delivery for several weeks due to the aggressive actions of the hawks.

Fish said her family is not concerned about the birds and she has taught her boys that the swooping behaviour is a natural instinct.

She noted that a provincial wildlife official was out to check on the situation several times last year and this spring.

She was told the Swainson's hawk is a protected species and an active nest cannot be disturbed.

Fish said she agrees with that and does not want to see the birds harmed. She added she was also told a year ago that the nest would be removed once the birds flew south.

"They didn't remove the nest," Fish said. "[The conservation officer] said he would be in touch with us and we never heard from him again."

On Thursday, residents told CBC News they had not seen much of the birds in recent days.

"It seems like they're staying more up the other side of the block," Peterson said.

Some speculate the family has taken up in another area where there is better hunting.

"If it would make everyone more comfortable and they want to take the nest without harming the birds, we're fine with that," Fish said. "We would have no problem with them moving the nest."

She added, however, that if the birds are determined — and like the area — they may simply rebuild.

Randall, however, is among those who are more convinced that "something should be done." Although no one has been harmed, she is concerned because she has heard of injuries from hawks in the past. "Nobody will [convince] me that they can't hurt you," she said.

Peterson said she is considering launching a petition to demand some action.

But she admits that would entail going door-to-door on her street to canvass for signatures.

"So, my husband will probably be the one who will go out and do this instead of me," she said.