February 5-11, 2019 (Week 6 of 52): Cold-Blooded Critters Just Chill for Winter

More than 150 cold-blooded vertebrates are native to the Buffalo-Niagara Region including fish, amphibians, and reptiles. These poikilotherms cannot regulate their body temperatures metabolically like mammals and birds. Instead, their temperatures are controlled by the surrounding environment and therefore drop as air and water temperatures drop in autumn. Most respond to the advancing cold by retreating to protected areas, where their body temperatures can stay above freezing, and then going dormant for the winter. Unlike mammals, this state of dormancy is triggered by cold, not hormones. Most herps (amphibians and reptiles) enter dormancy by late October or early November in our Region, while most fish do so a little later in autumn. However, it is noteworthy that some aquatic species stay active in the Great Lakes, Niagara River, tributary streams, ponds, and deep wetlands where water temperatures remain just above freezing for most of the winter.

Winter-active fish include yellow perch, walleye, northern pike, pickerel, bluegill, pumpkinseed, black crappie, lake trout, rainbow trout/steelhead, and brown trout. These fish continue to move and feed, albeit slowly in comparison to summer activity levels. They often stay close to the bottom where water temperatures are slightly warmer than at the surface, where ice may form. These fish feed most actively early and late in winter. Therefore, ice-fishing for them is often best shortly after ice forms and again just before ice-out. A few species, such as lake sturgeon and emerald shiner, migrate in autumn to over-wintering areas. One cold-hardy species, the burbot (an elongated deepwater fish in the cod family) brazenly spawns when water temperatures are just above freezing, typically during February and early March.

Many species of fish move to deeper water and/or retreat to cover objects and then go dormant for winter months. Deeper water areas are slightly warmer than surface water and are less likely to freeze, which would kill dormant fish. Their metabolisms drop significantly, in response to cold water temperatures. Therefore, they consume much less energy and survive winter on stored energy reserves. For example, common carp and brown bullhead settle to the bottom where they remain for winter, sometimes partially buried in mud. Largemouth and smallmouth bass cease feeding and lie dormant close to cover objects such as rocks and logs.

Active and dormant fish are at risk of “fish kill” when there is prolonged and deep snow on top of ice covering shallow lakes and ponds. Under those conditions, sunlight penetration into the water is inhibited, preventing photosynthesis (which produces oxygen) by aquatic plants and algae. Dissolved oxygen levels, essential for animal life, drop and fish will succumb over time. Such anoxic conditions are exacerbated in eutrophic waterbodies where there is a heavy load of decaying organic matter, which consumes dissolved oxygen.

Like winter-active fish, some aquatic and semi-aquatic amphibians remain active in near-freezing water during winter months, often under ice. Mudpuppies are permanently aquatic salamanders found in the Great Lakes, Niagara River, and tributary streams. They are active and feed all winter, and are occasionally caught when ice fishing. Red-spotted newts, the aquatic stage of red efts, remain somewhat active during winter months in ponds and deep wetlands. Some northern two-lined and northern spring salamanders do the same in streams and associated springs.

In contrast to aquatic amphibians, aquatic turtles and frogs spend most of the winter in a state of dormancy. This form of “hibernation” is called brumation for amphibians and reptiles. Their metabolisms slow significantly as water temperatures drop. For example, the heart rate of painted turtles drops to one beat every ten minutes. Oxygen exchange is limited to a small level that occurs through skin. Snapping turtles and midland painted turtles settle into mud at the bottoms of ponds, lakes, and other waterbodies and remain dormant for the winter. Map turtles and spiny softshell turtles, two species found in the Great Lakes and its tributaries, may migrate relatively short distances before going dormant in select over-wintering sites. Wood turtles and northern water snakes retreat to protected areas within or bordering streams and wetlands, including stream banks, pond banks, and muskrat mounds. Dusky salamanders escape to deep pools in streams where they lay dormant under rocks. Bull frogs, green frogs, northern leopard retreat to bottoms of ponds, deep wetlands, and other waterbodies where they remain dormant for winter.

Terrestrial herps need to either dig a burrow or find an existing animal den (e.g., chipmunk burrow) or other hideaway below the frost line where temperatures stay above freezing. Most salamanders and American toads dig their own burrows which may be 18 inches below the surface. Since snakes have no appendages for burrowing, they utilize existing animal burrows, crevices, rock piles, and similar earthen cavities. For example, eastern garter snakes and red-bellied snakes retreat to rodent burrows, ant hills, and rock piles. They often over-winter in large congregations which suggests that these essential hibernacula are scarce. Eastern milk snakes often retreat to rock piles and the foundations of older structures, and therefore may be found in basements and barns during winter months.

Remarkably, several species of frogs do not retreat below the frostline but instead burrow just a shallow depth under dry leaf litter where they freeze solid, with little ill effect. Some people like to refer to frogs in this frozen state as “frogsicles.” Four relatively common species in our Region over-winter in this way: spring peeper, western chorus frog, gray treefrog, and wood frog. Three of these four species (all except gray treefrog) respond quickly to warming temperatures in spring by thawing and then traveling to breeding pools where males “sing” to attract females. Spring peepers, a small species that thaws quickly, may occasionally be heard singing during winter warmups. These four frog species survive subfreezing temperatures by utilizing high concentrations of glucose-based compounds that serve as an anti-freeze in their blood and tissues. They also utilize protein “seed crystals” that facilitate ice formation in extracellular spaces rather than in tissues where it would inflict deadly damage. They survive the winter in “suspended animation” with no evident heartbeat, breathing, or other signs of life. Regardless, they fully regain bodily functions once they thaw in spring. Hatchling painted turtles exhibit similar adaptations and can also survive freezing. Those that hatch but do not emerge during autumn can safely over-winter and emerge in early spring.

Below are highlights of what you can expect to find outdoors in the Buffalo-Niagara Region this week. Those in bold/italics are new or substantially revised highlights to watch for this week. Check out the list of 300 publicly accessible sites at https://bnnatureblog.com/nature-sites/site-lists/alphabetical-list/ to find areas to explore in your neighborhood and throughout the Buffalo-Niagara Region.

Average Sunrise/Sunset (Day Length):

  • 7:23 AM/5:37 PM EST (10 Hours, 14 Minutes)
  • 1 Hour, 13 minutes of daylight longer than at Winter Solstice

Typical Weather:

  • Normal High Temperature: 32.0° F; Normal Low Temperature: 18.3° F

Lake, Pond, Stream & Wetland Conditions:

  • The Lake Erie water temperature off Buffalo remained at 32°F and the Lake Ontario water temperature off Greece (Monroe County) cooled to 35°F as of February 7, 2019.
  • Lake Erie is now mostly ice-covered while Lake Ontario is mostly ice-free, other than shore ice.
  • Water levels in most interior wetlands and vernal pools are near seasonal highs after a long period of normal or better precipitation and greatly reduced evapotranspiration rates.
  • Similarly, water levels in most ponds are close to seasonal highs.
  • Inland ponds, wetlands, and vernal pools are mostly ice-covered.
  • Many streams are now partly or mostly ice-free following the recent warmup.


  • With the onset of winter, most fungal fruiting bodies (e.g., mushrooms, bracket fungi) have been extinguished. The fungal “roots” (mycelium network) will survive the winter and produce new fruiting bodies during the appropriate season next year. Interestingly, fruiting bodies of some species of fungi (e.g., oyster mushrooms) remain viable during the winter and may disseminate spores during warm periods or in early spring.

Ferns and Grasses/Sedges/Rushes:

  • Freezing temperatures during late autumn killed remnant grass, sedge, and rush stems. The roots of these perennial plants will survive and sprout next spring.


  • Wildflower stems died back following late fall freezing temperatures. Roots and rhizomes of perennial wildflowers will survive and sprout next spring. Seeds of annual wildflowers will do the same.

Trees and Shrubs:

  • Some American beech trees will hold their dead leaves over most of the winter.
  • A few native shrubs and vines continue to provide fruit (soft mast) that is an important winter food source for a variety of birds and mammals: cranberry viburnum, staghorn sumac, and swamp rose.
  • In addition, one non-native species, multiflora rose, provides fruit consumed by wildlife.

Insects & Other Invertebrates:

  • Freezing temperatures during late autumn killed most adult insects and other invertebrates that have not migrated or entered hibernation. The vast majority of insect species in our Region over-winter as eggs or larvae/nymphs, although some species over-winter as adults.
  • On warm and sunny days in late winter, watch for “snow fleas” (springtails), especially at the bases of tree trunks in streamside areas. They emerge in large numbers and may appear like a sprinkling of pepper on the surface of snow. They apparently do not feed or mate but instead seem to wander somewhat aimlessly before returning below the surface at night.
  • Also watch for small winter stoneflies, winter craneflies, winter scorpion flies, and winter gnats.


  • Burbot (AKA freshwater cod) spawn throughout February and early March in the Great Lakes, forming writhing balls of a dozen or more intertwined fish.
  • During brief warm periods throughout winter, fresh steelhead from Lakes Erie and Ontario migrate into tributary streams (including Niagara River) in preparation for spring spawning. Steelhead are an anadromous form of rainbow trout that spawn in streams but live most of their lives in Lakes Erie and Ontario. All forms of rainbow trout are native to Pacific coast watersheds.
  • Some brown trout that spawned in Great Lakes tributaries and the Lower Niagara River in autumn remain in those areas through winter. Brown trout were introduced into our Region from Europe.

Amphibians & Reptiles:

  • With the onset of winter weather, essentially all amphibians and reptiles are now hibernating (technically considered brumation).

Water & Shore Birds, Gulls & Terns:

  • The annual buildup of “sea ducks” and similar waterbirds that over-winter in the Great Lakes and Niagara River is near its peak with impressive numbers of greater scaup, lesser scaup, canvasback, redhead, common goldeneye, bufflehead, white-winged scoter, surf scoter, black scoter, long-tailed duck, common merganser, and red-breasted merganser.
  • Watch for winter resident tundra swans congregating in open waters along the upper Niagara River (especially off Beaver Island, Buckhorn, and Niagara Falls State Parks).
  • This continues to be a good time to look for purple sandpipers feeding in rocky habitats above Niagara Falls.
  • This continues to be an excellent time to watch for rare species of gulls such as Franklin’s, little, black-headed, California, Iceland, Thayer’s, lesser black-backed, Glaucous, Sabine’s, and black-legged kittiwake among more common species such as Bonaparte’s and greater black-backed gulls. Such rarities add to the remarkable diversity of gull species – 19 species total – that have been observed along the Niagara River and bordering Great Lakes. The peak time is typically between mid-November and mid-January.

Birds of Prey:

  • Bald eagles can be found along the upper and lower Niagara River where good numbers are over-wintering.
  • Winter resident raptors will continue to occur in the region, especially in areas with extensive open grassland habitat, including northern harriers, rough-legged hawks, snowy owls, short-eared owls, and long-eared owls.
  • Snowy owls are frequently found along Great Lakes shorelines, such as the Buffalo waterfront, where they feed on ducks and other waterbirds.
  • Great horned owls have started to pair-up, form pair bonds, and establish nesting territories. Listen for their vocalizations, especially near sunset and sunrise, including duets consisting of a female and male singing nearly in unison (with male calls noticeably lower in pitch than those of the female).

Upland Game Birds:

  • Watch for wild turkey flocks in farm fields, along forest edges, and near bird feeders.


  • Watch bird feeders for the following songbird species that are part of this year’s “winter finch” irruption: purple finch, red crossbill, white-winged crossbill, common redpoll, hoary redpoll, pine siskin, evening grosbeak, and red-breasted nuthatch. Nyjer (AKA thistle) and black oil sunflower are the best seeds for attracting these species.
  • Bird feeders are also excellent locations to watch for arrivals of more typical migrant and over-wintering feeder birds such as dark-eyed junco, white-throated sparrow, song sparrow, and American tree sparrow.   Place seed such as white millet in ground feeders or directly on the ground to attract many of these migrants.
  • Bird feeders will continue to be active with year-round resident birds such as mourning dove, downy woodpecker, hairy woodpecker, red-bellied woodpecker, black-capped chickadee, tufted titmouse, white-breasted nuthatch, blue jay, northern cardinal, house finch, and American goldfinch.
  • Good tips for feeding birds are available from the Cornell Lab of Ornithology, online at http://www.birds.cornell.edu/AllAboutBirds/notes/BirdNote01_WinterFeeding.pdf
  • If you don’t have a feeder of your own, consider visiting a local nature center (see the 2nd to last column in the tables of nature viewing sites found under the “B-N Region & Sites” tab on this web page).
  • The northern shrike, a predatory passerine that breeds in Canada and Alaska, will continue to occur in the Region. Watch for them on prominent perches overlooking open and brushy habitats.
  • While most American robins have migrated south, small to medium sized flocks may still be encountered.
  • Small flocks of horned larks and Lapland longspurs and large flocks of snow buntings can be found in open farmland and other tundra-like habitats by snow buntings.
  • To stay abreast of bird sightings in the region, consult eBird, Genesee Birds, and Dial-a-Bird (see the “Resources” tab on this web page for more details).


  • Resident species of cave bats (big brown, little brown, and eastern pipistrelle [tri-colored] bats), woodchucks, and meadow & woodland jumping mice continue to hibernate. These species are true hibernators.
  • False hibernators such as the raccoon and striped skunk are mostly dormant, other than occasional feeding forays during relatively warm weather. In contrast, Virginia opossums stay active all winter other than brief denning during particularly cold weather.
  • Most eastern chipmunks are in a state of torpor. In this condition, which is not a true form of hibernation, chipmunks sleep but arouse frequently to feed on hoarded food. They may forage aboveground during mild weather.
  • Gray squirrels and southern flying squirrels continue to actively forage for cached acorns and other available food, other than during extremely cold periods. Similarly, red squirrels feed from middens of pine and spruce cones.
  • Watch for increased activity by gray squirrels. They mate in February and early March.
  • Watch bird feeders after dark for nocturnal visits by southern flying squirrels.
  • Some white-footed mice and deer mice spend the winter in nests they built in woodpecker holes, bird houses, and squirrel leaf-nests. Some rehab old bird nests by adding a roof and insulation.
  • Beavers continue to feed on cut branches they cached in shallow water near their lodges during the fall, and muskrats do the same with herbaceous vegetation cached near their lodges.
  • The mating season for beavers is January and February.
  • Watch for increased activity by coyotes, red fox, and gray fox as they are beginning courtship and mating.
  • Raccoon courtship and mating typically starts in early February and extends into March.
  • Ermine (AKA short-tailed weasel) have molted from brown to white pelage for winter months.
  • The mating season for mink is February and early March.
  • Black bears, an uncommon species in the Buffalo-Niagara Region but increasingly common to our south, are in carnivorous lethargy. In this state, which is not a true form of hibernation, a bear’s heart rate is significantly lowered but body temperature falls only about 10°F (substantially smaller drop than for true hibernators).
  • Black bear cubs are typically born in January or early February while sows are in a state of carnivorous lethargy. 
  • White-tailed deer continue to travel in herds. Finding food will continue to be difficult until the growing season begins.
  • White-tailed deer bucks typically shed antlers between mid December and mid February in the Buffalo-Niagara Region.

Be sure to find an opportunity to get outside this week to discover signs of the season.

Chuck Rosenburg


2 thoughts on “February 5-11, 2019 (Week 6 of 52): Cold-Blooded Critters Just Chill for Winter

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