Ticks have started to emerge from their winter hiding spots, particularly in southwestern parts of Finland.
Users of the 'punkkilive' map service, a collaboration between Turku University and pharmaceutical firm Pfizer, have already logged hundreds of tick sightings so far this spring.
Reports of individual sightings started appearing as early as February, according to Turku University biodiversity expert Ilari Sääksjärvi.
"We can say that tick season has now started, as spring has truly gotten underway, at least in southwestern and southern Finland," he said.
Ticks become active at just five degrees Celsius, according to Sääksjärvi, who noted that the critters are also unaffected by subzero night-time temperatures.
"When temperatures drop at night, they retreat into the leaves and needles, waiting until it warms up again," he explained.
Over the past few decades, tick populations have not only grown but also migrated further north as the climate warms.
According to the Finnish Institute for Health and Welfare (THL), the most common diseases spread by ticks in Finland are Lyme disease and tick-borne encephalitis (TBE).