Indoors it's pleasantly warm, while outside it’s cold. Nature is resting. Deciduous trees have shed their leaves, and many animals have migrated south or gone into hibernation. Yet even in winter, there is still plenty to experience in nature.
A Harsh Winter
In the Abraham Ledeboer Park, the drumming of a solitary woodpecker echoes as it marks its territory: woodpeckers are already busy carving out nesting cavities. Various species of tits search for food together with other small birds like goldcrests. In a group, they find safety; many watchful eyes are on the lookout for sparrowhawks and other predators. A goldcrest weighs about 5 grams, and such a tiny bird can lose up to 1 gram of body weight in a cold night. They must eat a lot to survive. A harsh winter can therefore be devastating for the population.
Middle spotted woodpecker, Abraham Ledeboerpark. Photo: Wim Bakker
Another bird that stays in the Netherlands during winter is the kingfisher. Despite its Dutch name IJsvogel (literal translation: Ice bird), a kingfisher does not cope well with harsh winters. If there is ice everywhere, the kingfisher starves, as its diet consists entirely of fish and other aquatic creatures. As long as the ponds are not completely frozen over, the kingfisher can still be spotted on our campus.
Kingfisher, Het Roessingh. Photo: Wim Bakker
Welcome Guests
Other bird species we encounter in winter are redwings and siskins. These ‘winter visitors’ come here to escape the severe winters of the far north. Siskins and redwings can sometimes be found in urban gardens, especially at the end of winter when seeds and berries become scarce outside the city. There’s often still something to be found in urban gardens—especially if people hang up seeds, peanuts, or fat balls. Occasionally, unexpected bird species are spotted at feeding tables, making participation in the National Garden Bird Count, held annually on the last weekend of January, quite enjoyable.
Insects in Winter
Insects are generally warmth-loving creatures, most commonly seen during summer. Yet, there are insects to be found year-round. Species like the large and small winter moth live up to their name and fly mainly at the beginning of winter. If you see a moth fluttering in your car’s headlights in November or December, it is undoubtedly a winter moth. In early spring, other species become active, such as the dotted border, early moth, March moth, and spring usher.
Mottled Umber, Abraham Ledeboerpark. Photo: Wim Bakker
Butterflies and moths go through four stages: egg, caterpillar, pupa, and adult butterfly. The stage in which they overwinter depends on the species. For instance, the brimstone butterfly overwinters as an adult in shrubs or dense clumps of grass. They have a kind of antifreeze in their veins, allowing them to survive even a harsh winter. With the first sunshine in February, you might just spot a brimstone butterfly, searching for the nectar of the earliest spring flowers.
Brimstone butterfly, Abraham Ledeboerpark. Photo: Wim Bakker
There are many ways to get through winter, and traces of some overwintering insects can be found. The yew gall midge, for example, causes galls in yew trees, which look like small pineapples. Inside such a ‘pineapple,’ a larva of the yew gall midge spends the winter. These galls have been found in several places on campus.
Gall of Taxomyia taxi, UT campus. Photo: Wim Bakker
Keep your eyes and ears open: there’s plenty to observe in nature, even in winter!
Biodiversity at UT
Strengthening biodiversity on our campus is one of our sustainability goals at the University of Twente. By improving monitoring, we gain knowledge about biodiversity on campus in general, which helps us decide on the best ways to support it. In 2024, we started the yearly Bioblitz, in which anyone can help monitor species via the app ObsIdentify. Several activities were organised to raise awareness of biodiversity (such as bird observation). A biodiversity council was established, where CFM (Campus & Facility Management) consult with biodiversity enthusiasts on how maintenance can contribute to an improved habitat for species. Furthermore, thanks to a Climate Centre grant, we are working on making data on green maintenance and biodiversity accessible for research and education.
Would you like to find out more about sustainability at UT? Please go to utwente.nl/sustainability.