Which factor is less likely to cause rodents to invade buildings?

High population density of other rodents is less likely to directly cause rodents to invade buildings compared to the other factors listed. While a dense rodent population can indicate an environment that supports their survival and reproduction, it does not inherently lead to new invasions of buildings. In fact, many rodents are territorial and will establish their own areas where they feel secure, which might not include human structures.

In contrast, extreme cold temperatures drive rodents indoors in search of warmth. Availability of shelter provides a safe breeding and nesting environment, while access to food and water sources is a primary motivator for rodents to invade human spaces. These factors are more directly linked to the behavior of rodents seeking out appropriate living conditions and resources, making the high population density of other rodents the least impactful factor in encouraging an invasion of buildings.