This story was originally published by High Country News and appears here as part of the Climate Desk collaboration.

Hungry black bears are flooding neighbourhoods, the university campus and even downtown streets in Missoula, Mont. Regional wildlife experts say the animals are looking for food thanks to a dearth of berries in the nearby hills and mountains. And that’s causing trouble: “We’ve had more break-ins into homes, going through screens, in the last five to six days than I have ever seen (at one time) in the last 27 years,” James Jonkel, Montana Fish, Wildlife and Parks Region 2 bear manager, said on Sept. 7.

After several months spent hunting elk calves and fawns, eating grasses and forbs, and digging for roots and tubers in the mountains, bears usually seek out berries as they start ripening in July, a seasonal shuffle that funnels them down to lower elevations so they can fatten up for winter. First come huckleberries, then serviceberries and chokecherries, and, finally, hawthorn. “The (hawthorn) berries are the size of olives in a normal year,” Jonkel said. Drainages choked with hawthorn bushes draw bears closer to Missoula, a small city of just over 70,000 people with many neighbourhoods that buffer the wilderness. There, the animals feast on unsecured garbage, bird feeders and backyard fruit trees full of apples, pears and plums. On the nearby Flathead Indian Reservation, bears enjoy raiding unprotected chicken coops.

But this year, black bears are nosing around homes sooner than normal, and doing so in higher numbers. “Something about this year just didn’t add up,” Jonkel said. Huckleberries, serviceberries and chokecherry crops have been patchy, and hawthorn berries are almost universally hard to find. The poor berry crop extends north through the Mission Valley and the Kalispell area. “We have also seen an increase in black bear conflicts across the entire Flathead Reservation this year,” said Kari Kingery, wildlife program manager for the Confederated Salish and Kootenai Tribes. “Residents that aren't normally accustomed to securing attractants from bears are seeing bears.”

Multiple factors likely contributed to the berry failures, which tend to happen cyclically, about once every seven years or so. Jonkel thinks an early summer hailstorm, which left brown bruises on some leaves, could be partly to blame.

In addition, this year’s sparse berry crop comes at the end of a record-breaking summer in northwest Montana. “The spring weather patterns are most likely the main contributing factor to poor berry production this year,” Kingery said. “The late frosts and cold spring, followed quickly by the hot, dry months in July and August, could have delayed and altered the plant development and productivity.” According to the National Weather Service, Missoula had its warmest-ever August. Research done by the USDA Northwest Climate Hub found that higher seasonal temperatures could impact huckleberry pollination and fruit production if flowering happens before bees are abundant.

Long-term changes to the region’s huckleberries are likely, too: A 2020 study predicts that the plants will migrate to higher ground and the berries will ripen earlier in the year due to climate change. Modelling by researchers at The Nature Conservancy and the U.S. Forest Service indicates an estimated 41 per cent reduction in suitable huckleberry habitat in the Pacific Northwest by 2080.

These ecological changes are ramping up the tension between humans and wildlife, and bears are dying as a result. When bears are able to find and consume human food, they're inadvertently rewarded and conditioned to keep scavenging. This behaviour often gets them killed. Cars struck and killed eight or nine on-the-move black bears in the last few weeks. Montana Fish, Wildlife and Parks recently euthanized two black bears that repeatedly broke into homes.

It’s too soon to know if this year will hurt the bear population or have any lingering effects. A food failure in the late 1990s was bad enough that Jonkel noticed fewer bears and cubs; numbers bounced back a few years later. When females are hungry, they may orphan cubs or their bodies may absorb fetuses to survive.

A poor berry crop is driving black bears into Missoula. A hot summer might be to blame. #ClimateCrisis #Wildlife

The influx of urban bears highlights the need for humans to change their behaviour. Montana Fish, Wildlife and Parks personnel have been busy trapping and relocating bears from downtown Missoula, where at least seven different animals are dumpster-diving near popular bakeries and breweries. The agency is currently working with garbage companies and businesses to install bear-proof dumpsters in high-traffic areas.

Groups like Bear Smart Missoula are also trying to reduce human-bear conflicts by preparing hazard assessments, developing a conflict-management plan and implementing community education programs. Residents in towns and outlying areas can help by not letting trash pile up outside, leasing bear-resistant garbage cans and gleaning excess fruit.

The poor berry year coincides with recent reports of two grizzly bears expanding their range into the Bitterroot Valley, south of Missoula. While the grizzlies haven’t gotten into trouble yet, their presence underlines the importance of sharing the land with predators in a way that’s safe and sustainable. “We’ve affected the habitat to such an extent that the wildlife are coming back,” Jonkel said. “We’re influencing it heavily with water, weird European plants, exotic agricultural crops and fruit trees. We’ve made the best habitat even better.”

Kylie Mohr is an editorial fellow for High Country News writing from Montana.