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RODENT CONTROL
In compliance with the provisions of the Prevention of Damage by Pests Act, 1949, it is the
duty of every Local Authority to take such steps as may be necessary to secure as far as may
be practicable that its district is kept free from rats and mice.
For the purpose of implementing the provisions of the Act, organisation and procedure was
similar to previous years, comprising inspection of properties to ascertain the presence of rats
and/or mice, treatment of properties found to be infested, recommendation and supervision of
structural and incidental proofing, and periodical control measures for the destruction of rats in
the City sewers.
A total of 2,160 properties were inspected under the Act, the properties varying from comprehensive
redevelopments in the course of construction, riverside food wharves, warehouses,
public and private catering establishments, blocks of offices, shops and factories to domestic
dwellings.
Altogether 598 complaints were received, either by notification or as the result of inspection
and of this total 534 infestations were subjected to control measures. In 64 instances no action
other than advice was necessary. These were mainly cases of suspicion, or where a mouse had
been seen by early morning cleaners, but the often long procedure of investigation had to be
carried out, not only to satisfy the occupier, who had co-operated by notifying the matter, but to
ensure that the occurence was not the fringe of a heavier infestation elsewhere in the property or
adjoining premises.
Such complaints do, however, indicate the awareness by employers and employees of even
minor nuisances, and their readiness to seek advice and assistance to resolve a problem. From
the rodent aspect alone, this is an attitude to be encouraged, as, in the past, many infestations
of rats and mice, some approaching a major degree, have been traced and eliminated as the result
of a complaint of a minor or even frivolous nature. Continual routine inspection over the years
has fostered this attitude, encouraged the public, and strengthened their co-operation.
The total of 534 infestations requiring control measures comprised 4 major and 43 minor
infestations of rats, and 3 major and 484 minor infestations of mice. Of the rat infestations
4 major, (21-200 rats) and 41 minor (1-20 rats) were of common rat (Rattus Norvegicus) character,
and the remaining 2 minor infestations were of ship, or black rat (Rattus Rattus) nature.
Treatment of these infestations entailed 3,581 visits for operational purposes and in the
application of control measures 9,784 initial baiting sites were selected for both rats and mice.
For the control of rats 3,160 pre-baits were laid which necessitated the use of 420 poisonbaits
to finalise the treatments.
These measures resulted in a minimum estimated kill of 609 rats and of this number 316
bodies were removed from the sites of the treatments. Others, not included in this figure, were
found on removal of structural or incidental harbourage providing nesting and breeding facilities.
The use of anti-coagulant rodenticides and other poisons entailed the application of 9,763
baiting points for the control of mice and 685 bodies were recovered.
The low level of Ship (Black) rat infestation manifest in recent years has been maintained
and the 2 minor infestations of this nature during the year under review is the lowest yet recorded.
To illustrate the diminished status of this species within the City, the comparable figure
recorded in 1948 was 698 rat infestations treated, comprising 668 ship and 30 common rat infestations,
and of the ship rat figure 249 infestations were in the major classification.
In reviewing the present position of this species, there are many contributory factors. Foremost
of these has been advanced techniques of control, the great improvement in general hygiene,
progressive demolition of old properties and redevelopment, systematic inspection and diminution
of re-infestation from outside sources.
The relatively low number of common rat infestation s was confined to the comprehensive
re-development sites in their varying stages of construction. These offer every facility and are,
in every way, conducive to infestation. All such sites were regularly inspected and the fullest
cooperation of the various contractors was received at all times having regard to the conditions
and labour involved.
Periodical treatment at 3 monthly intervals for the control of common rats in the sewers is
of primary importance in relation to the control of the same in surface properties. It is the purpose
of these measures to ensure that the rat population in the sewers is kept down to the lowest
possible level, thereby preventing infestation of surface properties via defective drainage.
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