Apart from the increased productivity of the land, mouse population outbreaks are also triggered by any of the following:
1. When the farming practice in a specific land in routinely changed to ensure continued productivity of different kinds of crops. In context of farming, crop rotation is often a good practice because it allows the land to breathe and increase its nutrient content. However, mice are also drawn into the farms because there is a continuous supply of food for them in these places by virtue of crop rotation.
2. When the farm is left undisturbed for a reasonably long time. Sometimes, because of good quality seeds and climate, farmers no longer till as often as they normally would. When cultivation is least, mice can freely roam around the farmlands without fear of being disturbed by human presence. Thus, they can reproduce without constraints.
3. Apart from humans, animals that graze can also scare away mice. However, when the grazing in the farm is reduced due to certain reasons, then again, mice would be able to roam around the farm without any fear whatsoever.
Farmers are already aware that each time they improve their farming practice in order to increase productivity; they are also opening bigger doors for mice infestation to occur. Over the years, this has been an acceptable trade-off. However, this supposed balance between increased income and increased damage is always compromised each time the infestation lasts longer that it ought to be or when the number of mice infesting exceeds what has been expected, something which can result to incalculable damages.
The possible reasons why a mouse infestation can last more than the average two-year duration are:
1. The breeding season of mice is extended. This happens when the mice start to breed early and ends the season late. A little discrepancy in the number of days mice breed is already sufficient to increase their population beyond what is expected.
2. Sometimes, when food remains plentiful even after two years of infesting, mice will opt to stay and feed some more. It is instinctive for mice to stay in a place where they are well-provided for and a farm with a lot of produce is the most ideal place for them.
3. Oftentimes, when an infestation occurs, farmers will also try to hunt down mice and chase them out of the farm although they know that the infestation will not ward off just like that. However, this procedure can greatly reduce the number of mice in an area. Thus, an extended infestation can be a result of the presence of a good nesting site. If the nesting site of the mice are well-hidden from farmers, their reproduction will be least disturbed.
4. Another huge factor that helps in mouse infestation control is the presence of natural predators. When the predators are severely outnumbered by the mice, then definitely, they will contribute so little in the control of these pests.
5. Mice population is also reduced in the two-year infestation period because of diseases and parasites. However, in the absence of these two, there is a high chance for mice to thrive longer than two years.
How About Plagues Caused by Mice?
It should be clear that mice are least likely to spread plagues because the only time this becomes possible is when their population reaches at least a thousand mice in a hectare of land. This is quite impossible to reach because at 100 mice per hectare, tremendous damage can already occur. Thus, food supply will not permit mice to reach the 1000 per hectare quota. Therefore, when it comes to mouse infestation, the real issue is not in human health or anything else, it is really more about crop damage.
So, what are these damages that we are talking about?
Mice like to eat what humans also love to eat. In most cases, they tend to damage cropping areas that produce cereals, maize, legumes, sorghum and pulses. They also like the vegetables that humans are so in need of. Examples of such are:
a) Peas, beans and other high-protein vegetables
b) Zucchini and other delicious green veggies
e) Melons and the fruits of crawly veggies
It is easy to spot a damage caused by a mouse. Since these pests are nibbling rodents, they usually leave obvious tracks behind them. Examples of such evidences are: a chewed leaf (you will know when a leaf is chewed when you see one), seeds with missing heads (mice always prefer eating the head part) and some bits and pieces of farm produce just scattered around.
In general, because mice love to nibble, they usually attack portions of the crop that are easiest to chew. These portions are the flowering node of the crop and the maturing heads of the seeds which are exposed. Since the crop flowers and seeds are both fundamental to crop productivity, the damages that mice can cause to them can result to a pre-harvest loss amounting to about 50% of the supposed harvest.
Thus, whenever mice attack during pre-harvest, farmers usually use zinc-phosphide baits in order to control their population. Farmers also place baits around their barns in order to discourage mice from entering the place. Nevertheless, these practices have been always insufficient in completely exterminating mice infesting in a farm. The most that control methods can do is to prevent mice population from growing too big since the size of the population is directly related to the total amount of damage.