Why are there no mice this year? - briefly
Unusually cold winters and a dry summer have limited food and breeding success, causing a sharp population decline. Intensive rodenticide applications in farms have further increased mortality, resulting in the current absence of mice.
Why are there no mice this year? - in detail
The noticeable decline in rodent populations this season can be traced to several interrelated factors. Climate anomalies have altered the availability of food and shelter. A prolonged drought reduced seed production and vegetation cover, limiting the resources that mice rely on for survival and reproduction. Simultaneously, unusually warm winter temperatures disrupted hibernation cycles, causing premature emergence when food supplies were still scarce.
Predator dynamics also shifted. Increased numbers of raptors and small carnivores, attracted by the same environmental stressors, imposed higher mortality rates on the remaining individuals. In addition, an outbreak of a hantavirus strain, documented in nearby regions, led to rapid die‑offs among susceptible colonies, further suppressing population growth.
Human activity contributed significantly. Expanded pesticide applications in agricultural fields eliminated insects that serve as supplemental protein for mice, while also contaminating the ground and water sources they depend on. Urban development projects replaced natural grasslands and hedgerows with concrete surfaces, fragmenting habitats and preventing dispersal between isolated pockets.
Lastly, genetic bottlenecks resulting from previous years’ low numbers have reduced reproductive vigor. Small, inbred populations experience lower litter sizes and higher juvenile mortality, slowing recovery even when external conditions improve.
Key contributors to the current scarcity include:
- Drought‑induced reduction in seed and plant matter.
- Unseasonal winter temperatures affecting dormancy patterns.
- Elevated predation pressure from birds of prey and mammals.
- Disease outbreak affecting rodent health.
- Intensive pesticide use diminishing food sources.
- Habitat fragmentation from urban expansion.
- Genetic decline due to prolonged low population density.