The story at the Hawaiian Humane Society is the same as for the Kauai, Maui and Hawaii island Humane Societies: Shelters are at overcapacity.

Dozens upon dozens of homeless dogs and cats have filled Hawaii’s shelters, awaiting adoption as more are surrendered due to economic hardship and the challenges of finding affordable, pet-friendly housing.

Local shelters are getting a much-needed boost from the Bissell Pet Foundation, a national nonprofit that on Monday kicked off its national “Empty the Shelters” event in partnership with Dogtopia, with sponsorship of adoptions at all four of Hawaii’s Humane Societies through May 15.

“This is a very difficult time for shelters across the country, with increasing owner surrenders due to the housing crisis and inflation as well as slowed adoption rates,” said Cathy Bissell, founder of Bissell Pet Foundation, in a news release. “With Dogtopia’s partnership, we are hopeful more pets than ever will find homes during this national event.”

The Hawaiian Humane Society kicked off the event a day early on Sunday, which was National Adopt a Shelter Pet Day.

From now through Sunday, HHS is offering all animals for a reduced adoption fee of $25. From Monday to May 15, adoption fees will be waived for all animals.

The Humane Society’s kennels have been over capacity with dogs since October, according to HHS spokeswoman Brandy Shimabukuro, and still are as the number of pet surrenders increases.

It is also kitten season, and more than 200 are currently getting care in specialized foster homes.

“We are still hearing that the lack of affordable, pet-friendly housing and inflation are the prevalent factors in families being compelled to surrender their pets, which is not unique to Oahu or Hawaii as a whole, but is exacerbated that much more by our state’s high cost of living,” wrote Shimabukuro in an email.

The Maui Humane Society is also holding an “Empty the Shelters” adoption special, which kicked off Monday and will last through May 15. On Maui, adoptions will be free for dogs over 6 months old, cats and small animals. Adoption fees for kittens will be reduced to $25.

The event comes at a time when many shelter animals are desperately in need of temporary fostering or adoption, according to spokeswoman Katie Shannon of MHS, which recently issued another plea for “SOS fosters” to help take in dogs due to shelter overcapacity.

Shannon also cited the lack of pet-friendly housing as a challenge, which has been the reason for an estimated 40% of all surrenders on Maui. There also has been an uptick in stray animals on the island, and officers are picking up about five per day, she said.

The Kauai Humane Society posted on Instagram that as part of “Empty the Shelters,” all animals over the age of 7 will be available for free, thanks to the Bissell Pet Foundation. Other animals will be available for a $25 adoption fee.

In mid-April, Kauai Humane Society Executive Director Nicole Crane posted a video on Instagram pleading for the public to adopt or foster a dog. The shelter on Kauai had taken in 300 dogs and had to divide its kennels to accommodate the influx.

While people have been adopting, she said, those adoptions have been slowing down, and the opportunity to transfer animals to rescue partners has decreased by more than 70%.

On Monday, the Kauai Humane Society said its kennels were still full, with multiple dogs housed together.

On Maui, Shannon said not only is pet-friendly housing a major challenge to find, meaning fewer people can adopt or foster, but shelters in Hawaii have few options when it comes to transfer opportunities to partner organizations.

On the mainland, sometimes a neighboring shelter has room to take in an animal.

“In Hawaii we don’t have that luxury,” she said. “We have to fly our animals. There’s no other option for them unless they’re getting adopted on-island.”

MHS still offers its “Wings of Aloha” program, but available flights have diminished, and getting an animal to a partner shelter takes much more time and planning than previously. Shelters on the mainland are also full.

There are a few happy tales, such as when a couple from British Columbia checked out a shelter dog — formerly a stray and now named Kade — for the “Beach Buddies” program, fell in love and took him home.

But many more dogs are still waiting for their forever homes, some for months, particularly larger ones over 50 pounds, which are more difficult to adopt out, said Shannon.

Bissell Pet Foundation’s “Empty the Shelters” event includes more than 350 shelters in 45 states.