Changes in Rodent Behaviour During Lockdown

Prior to the closure of many businesses across the UK, like most other Pest Control providers, the management of rodents, especially house mouse, in UK urban centres had become increasingly challenging. These are well documented but the overriding factors have been:

• Reluctance to enter plastic boxes
• Reluctance to feed on any single source of food
• Preference to feed by licking fats/grease
• Resistance to common second-generation anticoagulants
• Increased availability of street food
• Legislative Restrictions on exterior baiting

Changing Rodent Behaviour

 Peter spent some time in London supporting clients as a key worker to witness these changes in behaviour and have tips for pest control companies on how to utilise this unique opportunity whilst the Hospitality industry is still quiet.

Mice

Surprisingly mouse activity has only increased slightly (much lower than first expected). However, mice appear to have become more persistent and with the lack of human traffic have time to gnaw undisturbed, discover new food sources and make the most of the limited available food sources.

This has led to some interesting changes, we’ve seen evidence gnawing through brush strip and door frames to gain access to new food substances which whilst not uncommon previously is now much more prevalent.

Mice are also travelling further. Traditionally living close to food sources they are now moving further from their harbourage in search of new food sources. This has led to the most surprising change we’ve witnessed since the lockdown, Mice in Central London are actually taking bait in areas where bait take was previously rarely consumed. 

In central urban centres mice have been forced to feed on more carbohydrate-based foods rather than their previously preferred protein-based foods e.g. Rice, flour has been attacked in food store kitchens even though many kitchens still have enough cooking fat on the floor to maintain population levels. The reduction of available fats on hard surfaces to ‘lick’ has driven mice to feed on stored products in pantries. Mice droppings are increasingly found around kitchen grease traps, many of these were not emptied at the time of lock-down. The fat is becoming rancid and smelling, therefore attracting rodents to this source of food.

Rats

The lack of food from street litter and commercial refuse has made rats seek alternative food inside buildings. Rats have been found in cellar and basement areas to sites that have never suffered from rat activity.  15% of sites visited had new rat activity. Rats have made use of pipe and wire runs into buildings and in some cases simply gnawed through the base of wood doors 

Empty buildings have allowed rats to explore entry points previously difficult to explore due to the area being frequently visited by humans. 

Rats were observed scratching at soil and concrete where cooking oil was split. Even digging up the pointing between paving slabs - this type of activity uses lots of energy for relatively low levels of reward and demonstrates the lack of available food and a forced change of behaviour.

Gnaw marks on-top of plastic wheelie bins are increasing and the rubber bungs under euro bin waste containers have been extensively damaged. We found that sites that placed the wheelie bins next to a wall had a higher proportion of their bins attacked compared to sites where their bins were stored away from the wall. Indicating the rats were using the wall to climb onto the bin lid. 

Maximising the opportunity

The COVID-19 shutdown offers pest controllers and retailers the opportunity to totally eradicate long-standing internal mouse activity, with the increased use of baits combined with a change in practices. This will reduce call outs, follow up visits and save the costs of return visits.

With so many changes in behaviour witnessed in both rats and mice, here is how we are making the most of the opportunity.

• ‍Rodenticides are more effective. Both rats and mice have a significant reduction in alternative food; therefore traditional edible baits have become more effective. ‍
• Increase the numbers of baiting points where possible. Where sites have closed and no longer have a public presence use this opportunity to lay additional boxes in areas where baiting was not previously possible such as on restaurant floors and in public spaces. (subject to label directions and risk assessments) ‍
• Change how the bait is delivered. Open trays and cardboard tunnels are a cost-effective way of deploying additional boxes and they have proven to be more effective with a high take of bait from these compared to plastic boxes. Careful use of any exposed bait is required but work with clients to make this a safe practise.‍
• Change the type of bait. Baits with higher grain content are now being taken in preference to baits with high-fat content. ‍
• Continue to deploy proofing measures. Rats and Mice are seeking food sources more widely, ensure a special focus is put on removing brush strips (generally not very effective against persistent mouse activity)  and replacing with rodent-proof door seals. ‍
• Deploy Smart Solutions. Never has there been a better time to deploy smart solutions to your customers. The furloughing of staff means many premises are empty for long periods of time. Utilising smart allows you and the customer to remotely monitor premises so you can get on top of an infestation before it takes hold. 

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By demonstrating to clients that their investment in proofing and smart pest control is worth the investment, this allows pest control companies to become trusted partners. Become more than a supplier and engage at a more strategic level.

Read issue 69 of the Pest magazine here view the article below:

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