What to look for in nature in Vermont this May

Which warblers and other songbirds arrive in Vermont in May?

• Blackpoll warblers

  Arrive in large numbers through May · Backyards and street trees in the valleys; spruce-fir forest on the highest peaks later

  The Center’s May 2025 field guide says blackpoll warblers pass through Vermont in vast numbers in May and often turn up in backyards and street trees. The ones that breed here go to the montane spruce-fir zone on the highest peaks, the same habitat that holds Bicknell’s thrush. In a cool spring such as 2025, males settle at lower elevations because leaf-out is delayed higher up. During the breeding season a blackpoll averages about 12 grams, roughly the weight of two nickels, and by early September it has nearly doubled that.

• Bicknell’s thrush and the mountain birds

  High-elevation arrival late in spring; volunteer listening surveys are in June · High-elevation balsam fir forest

  The Vermont Breeding Bird Atlas calls Bicknell’s thrush a habitat specialist confined to high-elevation balsam fir forest, at the southern edge of its range in Vermont. It is globally rare, with fewer than 126,000 individuals, and the state ranks it S2B. The Center’s Mountain Birdwatch program sends about 100 volunteers to roughly 800 listening points in the spruce-fir zone each year, in June, and the 2023 State of the Mountain Birds Report found the blackpoll population in the surveyed areas falling about 4.5 percent a year, a 45 percent decline from 2010 to 2023.

• Early warblers, vireos and towhees

  Early May · Woodland edges and shrubby fields

  The Center’s May guides name palm, pine and yellow-rumped warblers as already in the state in early May, with black-and-white, blackburnian and black-throated green warblers arriving soon after. Its 2022 guide recorded pine, black-and-white and yellow warblers, common yellowthroats, blue-headed and warbling vireos, and eastern towhees near its Norwich office on a single early-May outing.

• Ruby-throated hummingbirds

  Soon after the yellow-bellied sapsuckers arrive · Woodland edges, gardens and feeders

  A Vermont eBird chart in the Center’s 2019 guide shows hummingbirds arriving shortly after sapsuckers, and the Vermont Atlas of Life explains why: early arrivals drink from sapsucker sap wells. Before they cross the Gulf of Mexico in migration, many hummingbirds nearly double their weight to 6 or 7 grams. The breeding atlas found them in 169 blocks, against 166 in the first atlas.

• Wood thrushes, scarlet tanagers and orioles

  Mid-May onward · Mature forest; orioles in open woodland and village trees

  Three bright voices reach the forests and edges as the leaves expand. The wood thrush dropped from 176 to 167 atlas blocks, and the atlas lists forest maturation, acid rain, nest predation and loss of wintering habitat as possible causes. The scarlet tanager nests in the canopy of large, mature forest and avoids edges; the atlas notes that late cold snaps and cold, wet weather that cuts its insect prey have caused die-offs in the Northeast. Baltimore orioles fell from 165 to 149 blocks between atlases, with the largest decline in the Northeastern Highlands.

When do bobolinks return to Vermont, and why does the hay-cutting date matter?

• A song over the grass

  Early May onward; singing is in the larger hayfields · Hayfields, pastures and grassy fields statewide

  The Vermont Breeding Bird Atlas says bobolinks reached Vermont after the 18th-century clearing of forest created grassland, and they can nest at up to three times the density found in the remaining native prairie. Their bubbling song is easiest to hear on a still morning. The atlas found them in 147 blocks in the second period, down from 156 in the first, with the largest declines in the Northeastern Highlands and Northern Green Mountains.

• Mowing and the nest

  First cut in late May or June is the danger · Working hayfields

  The atlas cites a Vermont study in which fields mowed in early June produced almost no surviving young, while waiting until late July or August raised output to nearly three fledglings per pair. It recommends delaying the first cut until at least July 7, or cutting before June 1 and then waiting at least 65 days. The Center’s 2026 guide adds that Champlain Valley farmers moved their first haying date about 10 days earlier between 2002 and 2019, while bobolinks still nest on their old schedule. Northern Woodlands counts the species as down an estimated 63 percent since 1966, and reports an incubation period of about 13 days. If you own or manage a large field, the Center asks you to write to grasslands@vtecostudies.org.

• World Migratory Bird Day

  Not yet posted for 2027; check the organizers · Anywhere with birds

  The international campaign’s own site places the U.S. and Canadian celebration on a Saturday in May, but nothing about 2027 had been posted on its page when we last looked, so ask the organizers. The simplest way to take part is to go out for an hour and submit an eBird checklist.

What is happening on Vermont lakes and rivers in May: loons and lake sturgeon?

• Common loons on the nest

  Nesting under way; the Center’s volunteers watch nests from mid-May through August · Lakes and ponds, strongest in the Northeast Kingdom

  The Center’s loon project counts 115 nesting pairs in Vermont, up from seven about four decades ago, and its volunteers record nesting success and chick survival through LoonCount and LoonMonitor. On lakes where water levels rise and fall, staff build floating rafts that act like islands, and floating signs mark nest areas. The Vermont Breeding Bird Atlas found loons in 27 blocks, up from 11, and lists ingested lead fishing gear as the leading cause of adult loon mortality in New England. Keep your boat well back from a loon sitting low on a nest.

• Lake sturgeon spawning

  Mid-April to mid-June, males first · Tributaries of Lake Champlain

  The Center’s May guide describes the lake sturgeon as Lake Champlain’s living fossil. Fish that prefer shallow water no deeper than 30 feet move up tributaries to spawn from mid-April to mid-June. Males spawn every two to three years and females every four to nine, males mature at 12 to 15 years and females at 20 to 25, and the fish can live up to 150 years. The species is on Vermont’s endangered list, and state biologists estimate it will take another 25 to 50 years before the population is considered restored.

Are turtles and snakes on the move in Vermont in May?

• Snapping turtles laying eggs

  May and June · Soft ground near still or slow water, including sand and gravel shoulders

  The atlas says females come ashore in those two months to bury their eggs. It calls the snapping turtle probably the most common turtle in Vermont, with large adults averaging about 16.5 inches long. If a turtle must be moved across a road, the atlas describes approaching from behind and wrapping your hands around the base of the hind legs, with the animal facing up and away from you, and warns that the neck reaches nearly the length of the shell. Always move a turtle in the direction it was heading.

• Wood turtles and painted turtles

  Active along streams and in ponds; basking on logs in sun · Moderate-gradient streams (wood turtle); soft-bottomed ponds and lakes (painted turtle)

  The wood turtle is ranked S2/S3 (uncommon and localized) and is a Species of Greatest Conservation Need, with illegal collection named as a problem. It can travel 1,000 feet or more from its stream to feed in fields. The painted turtle, by contrast, is common (rank S5) and is the one you will see basking in a row on a log. Report wood turtles and leave them where they are.

• Garter snakes and their relatives

  May, when nine of Vermont’s 12 snake species have been recorded on iNaturalist · Sunny edges, fields and stone walls

  The Center’s May guides call the common garter snake the most numerous and familiar, and note that it overwinters in underground dens. Dekay’s, ring-necked and redbelly snakes make their first appearances in May, and redbellies sometimes cross roads on warm, wet nights. Northern watersnakes and milksnakes are nonvenomous and rather common.

What are moose, bears and bats doing in Vermont in May?

• Moose calves

  Most calves are born in mid- to late May · Northeast Kingdom (about half the state’s moose, in Essex County) and along the Green Mountains

  Vermont Fish & Wildlife says calves weigh 25 to 35 pounds at birth, after a pregnancy of about 243 days, and that the cow and calf stay bonded until the next spring. The department describes the moose population as relatively stable at around 2,000 animals. Give a cow with a calf generous room, on foot or on the road.

• Black bears in the wet woods

  Through the month; cubs were born in winter · Forested wetlands, beaver ponds and stream banks

  The department says bears stay mostly near forested wetlands, beaver dams and rivers from den emergence through July, eating wetland grasses and green leafy plants, which have limited nutritional value. The cubs arrived in the den in winter, litters average two, and they stay with their mother about 16 months. The department’s population goal is 4,500 to 6,000 bears. Natural food is thin this time of year, so a bird feeder or open garbage can becomes a target.

• Bats returning

  Eastern red bats arrive in northern New England in May · Evening skies over fields and water

  The Center’s 2023 May guide notes that eastern red bats arrive back in northern New England in May. Watch the sky above a pond or field at dusk once the evenings are mild, and note what you see.

Which wildflowers, butterflies and bees can you find in Vermont in May?

• Trilliums, columbine and foamflower

  Late April into May, and for a short time in each place · Rich woods, cool moist edges and seeps, warm rocky ledges

  The Land Trust lists white, red and painted trillium, columbine, foamflower, trout lily, spring beauty, golden saxifrage, early meadow rue and blue cohosh for this window. Columbine often grows on warm, rocky ledges and foamflower in cool, moist edges. Take photographs and leave the plants, because red trillium and lady’s slipper can take many years to produce a first flower. The Land Trust suggests the Hinesburg Town Forest and Catamount Community Forest as places to look.

• Lilacs and the maples

  Lilac leaf-out is now about three days earlier per decade than in 1965 · Gardens and yards statewide

  The Center’s 2021 guide reports lilacs in Vermont leafing out about three days earlier per decade since tracking began in 1965, and the sugar maple season shortened by about three days over the past 50 years. Its 2022 guide invites readers to report sugar maple leaf-out on iNaturalist using the Plant Phenology field.

• Fiddleheads at the tail end

  Harvest usually starts about April 20 in central Vermont and lasts three to four weeks · River banks and floodplains

  Northern Woodlands says stems can grow six inches in a day and turn bitter, so the best picking is early. By mid-May the season is ending in the valleys. If you pick, boil or steam the fiddleheads for ten minutes, never strip a crown bare, and ask the landowner first.

• Mourning cloaks, azures and the West Virginia white

  Early spring butterflies fly in May; the bog elfin only in late May · Woodland edges, wet woods, bogs and fens

  The Center’s 2026 guide says 2026 is year four of the five-year Vermont Second Butterfly Atlas and that observations can be logged on eButterfly. Mourning cloaks and eastern commas overwinter as adults, so they are among the first on the wing, with azures and elfins close behind. The West Virginia white is a Species of Greatest Conservation Need that lays eggs on toothwort. The bog elfin has never been recorded in Vermont, though late May is the only realistic window to find one, perhaps on black spruce in a Northeast Kingdom bog.

• Bumble bees and blueberry bees

  Only queens are out in May · Fields, blueberry plantings and sandy banks

  The Center’s 2020 guide says Vermont has 13 bumble bee species, three of them extirpated, and that only queens fly in May. The rusty-patched bumble bee has not been seen in Vermont since 1999. University of Vermont research reported by the Center found that more wild bees meant bigger, more abundant and earlier blueberries on commercial farms, while the first ripe berries do not come until late June. Ground-nesting bees dig in sunny, sandy, disturbed spots and are mostly harmless.

What is May weather like in Vermont, and when is the last freeze?

• Frost after the buds open

  Any clear, calm night through the third week; see the freeze table below · River valleys and cold hollows especially

  A warm April can lure plants out before the median last freeze. A clear, still night after a cold front is when frost settles in low spots. Look up your own town on the Vermont frost dates page.

• Dry fuel and burn permits

  Spring wildfire season before green-up · Fields and woods with last year’s grass

  The Center’s 2015 and 2019 May guides both mention spring wildfires in Vermont. The Department of Forests, Parks and Recreation requires a Permit to Kindle Fire from your town’s fire warden for any open burn, and wardens ban burning when conditions are hazardous. The department and the National Weather Service in Burlington run a fire weather awareness campaign each spring.

• Thunderstorms and the trail season

  Thunderstorms begin to build in May; high trails open around Memorial Day · Statewide; the Green Mountains and Mount Mansfield

  The National Weather Service office in Burlington publishes local storm reports, spotter reports and past event summaries on its website. The Green Mountain Club says mud season runs through late May and hikers should stay off high-elevation trails until they dry out, typically by Memorial Day. Its closures are updated weekly on TrailFinder, so check before a high hike.

When is Vermont’s last spring freeze?

How much daylight does Vermont gain in May?

What can you see in Vermont’s night sky in May 2027?

• Eta Aquariid meteors, an excellent year

  Peak nights May 5 to 6 and 6 to 7; best in the last hours before dawn · Southeast sky, toward Aquarius

  These meteors are grains shed by Halley’s comet, and they fall between roughly April 19 and May 28. Because the Moon is new on May 6, no moonlight hides the faint ones. The American Meteor Society expects medium rates in the final stretch of darkness, and SeaSky puts the Northern Hemisphere at about 30 an hour at best. In Vermont the shower’s constellation, Aquarius, rises only shortly ahead of dawn, so expect to see fewer than observers farther south.

• Flower Moon and a seasonal Blue Moon

  Full at 6:59 a.m. EDT on Thursday, May 20; look on the evening of Wednesday, May 19 · Eastern horizon at dusk

  Burlington’s Moon comes up at 8:03 p.m. on May 19, a quarter of an hour before sunset at 8:18 p.m., and it is 99 percent lit (U.S. Naval Observatory). Nearly full on the 19th and exactly full the next morning, it is the Flower Moon. SeaSky also labels it a Blue Moon, using the older seasonal count in which the third of the four full moons of one astronomical spring gets that name (the fourth, on June 19, closes out the season). No month in 2027 holds two full moons, and the Moon will look its usual color.

• Mercury after sunset

  Easiest from mid-May to early June; farthest from the Sun on May 28 · Low in the northwest, roughly an hour after sunset

  For the northern states this is the planet’s best evening appearance of the year. Sunset in Burlington is at 8:26 p.m. on May 27, so the window runs from roughly 9:10 to 9:55 p.m., and you need an open view toward the northwest. The planet is at its brightest in mid-May and dims through early June.

• Moon with Jupiter and Mars

  The Moon visits Jupiter on May 12 and Mars on May 13 · Southwest to south after sunset

  Wednesday evening, May 12, finds a half-lit Moon about a degree from Jupiter. Twenty-four hours later it has moved on and stands roughly 3 degrees from Mars.

• Venus and Saturn at dawn

  Nearest each other at dawn on May 7 · Hugging the eastern horizon before sunrise

  The pair draw within about 0.6 degrees, but both hug the eastern horizon and Venus gets up barely an hour before sunrise. Bring binoculars and a clear low view, and count it a bonus. Saturn has just returned to the dawn after passing behind the Sun in April.

• Milky Way season begins

  Short moonless windows early and late in the month (our own calculation) · Low in the south, before dawn

  The brightest stretch of the galaxy starts rising before dawn in spring. At Vermont’s latitude our own calculation gives only short moonless windows, in about the first ten days of May and again in the last few days of the month. Use the cloud guide to pick a clear night.

What can Vermont families do outdoors in May 2027?

Safety notes for May in Vermont