652 MURIDAS—MUS 
destroying far more than they eat by tainting it with their 
droppings and unsavoury odour. By climbing curtains and 
blinds they reach suspended bird-cages, stealing the seeds, and 
not infrequently injuring or killing the birds. In stores, 
warehouses, barns, granaries, and cornstacks they are, of 
course, an unmitigated nuisance, and the cause of great 
pecuniary loss. Immune from attack and multiplying in hosts, 
they drill the whole interior of a cornstack, forming a labyrinth 
of runs, and occasionally—with the assistance of Harvest and 
Field Mice—make incalculable havoc amongst the grain. At 
threshing, notwithstanding the fact that vast numbers succeed 
in escaping, hundreds may be killed in a single rick." 
Like rats, the House Mouse shows a propensity for 
following a definite track to and from its hole; advantage 
may be taken of this habit in trapping mice. It is often 
said to be suspicious of traps, especially those smelling of 
previous occupants; Adams (JZS.) says this is difficult to 
prove or disprove, but he is inclined to disbelieve it, and 
thinks that when House Mice refuse to enter traps, it is either 
because they do not perceive the bait, or else because there 
is other food more to their taste near at hand. They will 
sometimes jump over traps placed in their path. Once when 
much troubled with mice, we set a trap between a fender and 
chimneypiece, through which aperture we had seen a mouse 
running on several occasions from the fireplace. We sat 
quietly watching the trap; in due course the mouse came out 
and leapt safely over the trap; we gently tapped the floor 
with a foot, and the mouse turned and jumped back again. 
A few minutes later the mouse and we repeated this perform- 
1 This species frequently plays a great part in the development of a mouse plague. 
Perhaps the most serious instance has been afforded recently by the great mouse 
plague in South Australia and Victoria, in which the House Mouse was the chief 
species involved. The plague developed in the bush as well as in the wheatland in 
1916 and 1917, after two abnormally heavy harvests. The wheat had been sold to 
the British Government, and it lay stacked in bags ready for shipment. Ships were 
lacking ; and the stacks remained unprotected from a possible attack by the rodents, 
As cold weather approached, the mice invaded the stacks and quickly produced ruin 
and disease. The damage done to wheat is estimated to be well over £1,000,000, 
and much damage was done also to other property. Myriads of mice were present ; 
thus 70,000, weighing about one ton, were killed in an afternoon in one wheatyard 
alone (Hinton, Rats and Mice as Enemies of Mankind, Economic Series, No. 8, 
British Museum, 1918, p. 41). 
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