View report page

This total comprised 7 major and 105 minor infestations of rats, and 84 major and 3.9 minor
infestations of mice. Treatment of these infestations entailed 4,996 visits for operational
purposes.
In the application of control measures for rat infestation, 9,769 pre-baits and 679 poison
baits were laid. These measures resulted in a minimum estimated kill of 902 rats, and of this
number 506 bodies were removed from premises. In addition 62 rats were destroyed by trapping.
The use of Warfarin anti-coagulant rodenticide for the control of mice resulted in 1,296 bodies
being found, no records are available of the results obtained by Pest Control undertakings servicing
premises periodically.
In 35 instances structural rat proofing was carried out by owners or occupiers and in 3
instances defective drainage resulting in rat infestation was remedied. Incidental rat and
mouse proofing in the nature of removal of harbourage provided by unnecessary accumulations
has received detailed attention, and in this respect the assistance received from the Director of
Public Cleansing and his Inspectors has been invaluable.
As in the past, rat infestation was in the main of Ship rat (Rattus Rattus) character. Infestation
of Common rat (Rattus Norvegicus) in surface properties showed a slight increase and 15
infestations were the subject of control measures.
The downward trend of rat infestation manifest in recent years continued and a further
decline in the number of infestations treated, and the numerical quality of the same has been
experienced. The number of major infestations (20 rats or over) was the same as for the previous
year (7) but of this number 5 were borderline infestations, just qualifying for this category. In
the minor classification there was a 25% reduction.
The Common rat infestations were mainly confined to re-building sites which offer every
facility and are in every way conducive to infestation, but taking into consideration the vast
reconstruction carried out in recent years, the size of the sites, and wide distribution of the
same, rat infestation has not in any way reached the degree visualized at the onset of rebuilding.
From the moment the contractors occupy a site, the inducement to infestation is provided. Huts
are erected, slightly raised from the ground thereby offering harbourage, obsolete drainage is
removed, and as the site progresses structural harbourage, although temporary, is available, and
to this must be added the incidental nesting facilities provided by the vast quantities of materials
and accumulations common to these sites. The temporary canteens provided for the workmen
are in the main well maintained but nevertheless are conducive to rats and mice. The principal
food supply is, however, offered by the numerous workmen employed on the sites who, preferring
to eat their meals other than in the dining room provided, distribute food over the entire site by
haphazard disposal of remains and with utter disregard to the fact that they are encouraging
infestation. All building sites were inspected periodically and when such conditions were found
to exist the necessary action was taken by the contractors as far as practicable having regard to
the conditions and labour involved.
Summarising the position of rat infestation in relation to surface premises, and the decline
in recent years, there are several contributory factors. Among the foremost of these are effective
control measures, a higher standard of hygiene generally and a steady improvement in
structural conditions. In addition owners and occupiers have become rat conscious and readily
seek advice and assistance.
The majority of catering establishments, public and private, numbering approximately 1,000
have been inspected during the period under review, and the improving standards of hygiene and
structural conditions have made a contribution to the present position.
The importance of hygiene in the field of rodent control, embracing proper garbage disposal,
food storage and elimination of structural and incidental harbourage must be emphasised. This
is essential to the permanent control of commensal rats and mice and the application of control
measures should be regarded as supplementary to hygiene.
The gradual increase and wider distribution of mice infestation apparent in recent years and
coinciding with the decrease of rats has not been quite so noticeable, there being a reduction of
32% in major infestations treated, while the number of infestations in the minor category remained
constant.
In reviewing this problem there appears to be a connection with the comparable decrease in
cat infestation, and when allied to other factors which must be considered, such as the pattern
of behaviour, embracing the ability of mice to accept harbourage and food supply which would be
insufficient for rats, general feeding hfibite, and ability to live without water, it might well be
that the balance of nature has been upset, and that the absence of rats has left the Way clear for
mice.
Mice, unlike both species of rats which are fairly stable in behaviour, are best described as
mercurial. They are on average about 25 grammes in weight and the food intake in 24 hours is
consequently very small — between 3 and 5 grammes, so that very small quantities of food are
14.