Hedgehogs require sufficient fat reserves before hibernation onset, and urban garden conditions that reduce prey availability can cause insufficient weight gain leading to death during winter.
Hedgehogs dying from insufficient fat reserves before or during hibernation experience a slow decline from malnutrition and hypothermia. Late-born juveniles face the most acute risk — they have limited time to gain weight before temperatures force hibernation onset. Urban gardens with limited prey availability due to pesticide use, hard surfaces, and tidiness create food deserts that prevent adequate weight gain. Supplementary feeding with appropriate food and water in September and October directly saves lives with minimal effort required.