1.   Once poison has temporarily reduced rat populations to almost zero, predation by barn owls can slow the recovery.

2.   The defendant had allowed the rat population on his farm to grow too large.

3.   As long as there are enough cats to keep the rat population under control, the farmers are happy.

4.   But Calhoun was convinced that his mice and rat populations were an accurate model for humans.

5.   It has been a season marked by torrential rains and by an increase in the rat population.

6.   No really hard numbers exist on the rat population in New York City for that very reason.

7.   The problem is what happens if the disease jumps, through the fleas, to a healthy rat population with few resistant members.

8.   A sudden increase in the rat population led to the attacks on people, it quoted experts as saying.

9.   The rat population can be reduced and eventually eradicated as their food source is removed.

10.   The program resumed last year due to the booming rat population, she added.