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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 practicable
that their district is kept free from rats and mice.
Compliance with requirements of the Act comprised inspection 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 three-monthly treatments for the destruction of rats in
the City sewers.
A total of 2,125 properties were inspected under the Act, the properties varying from comprehensive
re-development sites in the course of construction, multi-occupied blocks of offices,
riverside food wharves and warehouses, public and private catering establishments, shops and
factories to domestic, dwellings.
Altogether 534 complaints were received, either by notification or as a result of inspection,
and of this total 471 infestations were subject to control measures. In 63 instances no action
other than advice was necessary.
The total of 471 infestations requiring remedial measures comprised 7 major and 50 minor
infestations of rats, and 3 major and 411 minor infestations of mice. Of the rat infestations, 7
major (21/200) and 48 minor (1/20) were of common rat (Rattus Norvegicus) and the remaining 2
minor were of ship (black) rat (Rattus Rattus) nature. The numerical density of the 7 major infestations
was sufficient to exclude them from the minor scale, although they were in the main,
low in the major scale.
Treatment of these infestations entailed 4,302 visits for operational purposes, and in the
application of the control measures 10,572 initial baiting sites were selected for both rats and
mice. For the ccntrol of rats 4,896 pre-baits were laid which necessitated the use of 522 poison
baits to finalise the treatments.
These measures resulted in a minimum estimated kill of 859 rats, and of this number 396
bodies were removed from the sites on completion of the operations. Others were found in several
instances following removal of structural or incidental harbourage affording nesting facilities.
The use of anti-coagulant rodenticides and other poisons entailed the application of 9,700
baiting-points for the control of mice and 595 bodies were recovered.
In 10 instances structural rat-proofing was carried out by owners or occupiers, and in 11
cases defective drainage resulting in common rat infestation was remedied. Incidental rat and
mouse proofing in the nature of removal of harbourage provided by unnecessary and undisturbed
accumulations has again received unremitting attention.
The Common rat infestations were mainly confined to building sites which provide every
facility and are therefore conducive to infestation by both species, but bearing in mind the vast
amount of re-development completed since 1950, and that now in progress, plus prior demolition,
infestation has not reached the degree visualized and expected at the outset of reconstruction.
From the time the footings of the sites are completed inspections are made at frequent intervals,
and any necessary action taken, and fullest co-operation has at all times been received from the
various contractors.
The low level of ship (Black) rat infestation gradually obtained since 1951 has been maintained
and only 2 minor infestations of this nature were treated during the year. For comparison,
in 1947, 643 infestations were treated and of that number 595 infestations were of ship rat character.
To illustrate further the diminished degree of rat infestation, numerically and in distribution,
the up-to date summary collated from detailed records kept since 1944 is included as useful information.
It should be understood that the figure referring to rat infestation is the combined total
of ship and common rat infestation, the former comprising until 1957, 90% of infestation. It is
also emphasised that the estimated number of rats destroyed is the absolute minimum while the
total in the bodies found column is the sum of those removed from premises by the operators, and
and does not include any subsequently found on elimination of structural or incidental harbourage.
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