What a Mild Winter Means for Wildlife
By Tommy McCarthy, Environmental Educator
It’s no secret that this winter has been fairly underwhelming when it comes to consistent freezing temperatures. Today I looked back at some of my wildlife photos from February 2021, and the images are full of wintry backgrounds that evoke memories of sitting in the cold, snow-blanketed, and quiet woods. As I write this in early February of 2023, it is 50 degrees and sunny. We have had a few sparse streaks of freezing days, but the winter weather is just not sticking. Reflecting on past years and comparing them to this one, I began to wonder how the mild winter might be impacting our wildlife.
At first glance, it is clear that the lack of snow makes it easier for animals to forage and find food. If you have a bird feeder, you may be noticing less traffic compared to previous winters because of this - birds are easily able to find enough food without snow on the ground, and don’t need to burn as much of their energy keeping themselves warm. Mammals that forage and hunt also benefit and can easily find enough to sustain themselves on the open forest floors. On the other side of that coin however, these animals may be at increased risk of getting ticks and tick borne illnesses. Ticks only become dormant when the ground is covered by snow or when temperatures stay below 35°F, so a warmer winter with no snow means that ticks remain active for a longer portion of the season. Additionally, ticks only start to die when temperatures are sustained at below 15°F, so more may survive this winter to reach the age where they can reproduce. Not having to worry about ticks is something I usually appreciate as a silver-lining to hiking in the bitter cold, but this year the risk remains and could worsen in the months to come.
The mild winter seems to have some negative and positive effects for wildlife that remains active - but what about animals that hibernate through the season? Some amphibians and reptiles such as toads and box turtles burrow underneath the soil during winter and enter a period of inactivity known as brumation. The impact that a mild winter can have on these animals is a bit harder to intuit. Normally, these critters actually benefit from the insulation that a blanket of snow provides. Without that extra layer of protection, the short bursts of freezing days we are experiencing could lead to higher mortality rates as frost more quickly penetrates deeper into the soil. Some insects are also negatively impacted by the temperature fluctuations and overall milder season. If the trend of warmth remains strong, bumble bees can mistakenly emerge from hibernation before the early flowering plants they rely on have bloomed.
All in all, while we may think a warmer winter makes it easier for animals to survive, there are more nuanced interactions that occur in our environment as the seasonal weather deviates from what has historically been normal. It is difficult to predict how the smaller individual impacts of increasingly mild winters and variable snow cover will culminate to affect the ecosystem at large.
Traver, T. (2016, January 7). How a warm winter impacts local wildlife . The Adirondack Almanack. Retrieved February 9, 2023, from https://www.adirondackalmanack.com/2016/01/a-warm-winters-winners-and-losers.html
Tiedeman, M. (2020, December 10). Why is it good to have the ground covered by snow? Soils Matter, Get the Scoop! Retrieved February 9, 2023, from https://soilsmatter.wordpress.com/2017/02/15/why-is-it-good-to-have-the-ground-covered-by-snow/
Koppel, O., & Kerr, J. T. (2022, July 28). Strong phenological shifts among bumblebee species in North America can help predict extinction risk. Biological Conservation. Retrieved February 9, 2023, from https://www.sciencedirect.com/science/article/abs/pii/S0006320722002282?via%3Dihub