Acorns are dropping across Connecticut but depending on where you live, you may see and hear a lot or none at all.
Scientists at the Connecticut Agricultural Experiment Station are reporting a highly variable year for acorn production in the state. The findings are part of observations from 575 individual red and white oak trees at 12 locations throughout Connecticut, according to the CAES.
The findings are part of the Oak Mast Surveillance Program, a collaborative effort among several states — including Connecticut, New Jersey, Pennsylvania and Virginia — who have completed their annual acorn assessments and have reported average red oak acorn crops in 2025. Except for Virginia, which had a good white oak acorn crop, all other states reported fair to poor white oak acorn crops.
Once a common component of Connecticut forests, white oaks have diminished across the landscape in recent years due to repeated insect defoliation and drought, said Joseph Barsky, a lead forest researcher for the study. According to the U.S. Drought Monitor, the southern part of the state has been in abnormally dry or moderate drought conditions for most of the summer. Currently, the entire state is under abnormally dry conditions. Barsky said that prolonged drought and climate conditions can impact acorn production.
“White oak trees continued to exhibit crop failures across all areas of Connecticut, a concerning trend which has been observed for the last decade. Prolonged periods without adequate white oak acorn production are leading to fewer seedlings becoming established in our forested areas,” Barsky said.
“Over time, this shift will lead to a reduced component of white oak in our future forest and negatively impact the existing ecological processes and associated industries that depend on white oak,” he added.
But it’s not just in Connecticut, white oaks have been seeing a decline across the United States, according to Barsky. Several initiatives are underway to save white oaks, including the White Oak Initiative, to focus and advocate for white oak regeneration. The white oak was made the official state tree of Connecticut in 1947.
This fall, a bumper or mast crop of acorns is occurring among red oak trees in the northwestern corner of Connecticut, while areas in the northeastern sections are experiencing a good acorn crop, scientists said. The central and southern regions of the state are experiencing an expected widespread crop failure, following a bumper crop in those areas last year, according to scientists.
“Hikers may find some trails in Litchfield County this fall to be completely covered in acorns,” said Barsky.
A significant increase in acorn abundance that occurs as compared to previous years is a phenomenon referred to as either a “mast year” or “bumper crop year,” officials said. Mast seasons remain a poorly understood phenomenon because scientists can’t replicate the amount of variables that may be responsible for them including weather, climate, soil, chemicals and external factors.
While scientists aren’t quite sure why bumper crop years occur in oak trees, the phenomenon has a direct impact on wildlife such as rodents and deer.
“A bumper crop can drive several ecological processes in our forests, such as the opportunity to help maintain and perpetuate declining oak populations while providing a nutritious food source to sustain wildlife populations throughout the winter months,” Barsky said.
Mice, a common carrier of Lyme disease and a well-known host for ticks, can often see their populations multiply with an abundance of acorns. The acorns act as an important food source for them over winter, according to experts at the CAES. Some mice have been found to harbor over 200 ticks, with an average of about 23 ticks per mouse, according to experts.
“Masting events can also lead to higher rodent populations, which serve as primary reservoir hosts for numerous human pathogens including the bacteria that causes Lyme disease,” said Dr. Scott Williams, chief scientist for the Connecticut Department of Environmental Science and Forestry.
Deer on the move?
Acorns from oak trees are a vital food source for whitetail deer, especially in rutting or mating season, which begins in November. The more acorn production, the less deer have to travel to find them, leading to fewer road crossings, according to officials.
“During years when there are fewer acorns available, deer tend to move greater distances but not outside their normal home ranges ‘living areas’ they have established. They are resourceful animals and browse on a wide variety of woody plants and like other animals may gravitate toward urban interfaces utilizing bird feeders and consuming ornamental plantings when available,” said Andrew LaBonte, state wildlife biologist with the state’s Department of Energy and Environmental Protection.
“There is an increased risk to motorists when resources are lower. However, we also see an increase in harvest during times when fewer acorns exist as deer are moving more, which provides opportunities that may not otherwise exist when resources are abundant,” Labonte said.
According to AAA, between 2019 and 2023, there were 4,791 deer crashes in Connecticut. The number of crashes varies from year to year, with 2022 having the most crashes and 2023 having the fewest. While deer collisions can happen throughout the year, the state tends to see a spike in the fall, with 417 deer-related crashes between October and December 2023, AAA data showed.
The number of deer collisions is down from the early 2000s, when the deer population was at its height, according to Labonte. In 1996, there were an estimated 150,000 deer in Connecticut.
As the days get colder and the nights are darker longer, experts are warning Connecticut motorists to stay alert as the chances of colliding with deer are greatest during the final months of the year. According to the AAA, deer crashes are most common between October and December for two reasons: Mating season and daylight saving time.
The mating, or rutting, season for deer in Connecticut runs from late October to mid-December, with the peak being the last two weeks in November, LaBonte said. During this time, mature bucks become increasingly active and less cautious to establish dominance within their territory. Deer also commonly abandon typical daytime habits and begin moving about in search of a mate, according to DEEP.
“Mating season for deer begins mid-November/December and while males are focused on chasing females, they pay little attention to much else. Females running from males the same,” LaBonte said. “Motorists need to be cautious especially when low light conditions exist. Laws already exist to minimize accidents such as speed limits and cell phone use while driving, if there’s a time to abide by those laws, it’s during the rut especially.”
Stephen Underwood can be reached at [email protected].