Urban Bats

Urban bat camp issues

Cairns Colony 2011 (S. Amesbury)

Sydney Bat roost (S. Amesbury)

Sign near urban bat colony near Singleton (image: wollombi)

Royal Botanic Gardens (S. Amesbury)

Urban bat camp (Image WhitA)

Flying-foxes in towns and cities are a great source of delight for some people; for others they are tiresome backyard fruit thieves or noisy neighbours.

Urban areas are essential habitats for flying-foxes. There is no practical way of evicting and keeping them out of towns and cities, so it is in the interests of all concerned to manage roost sites to limit the impact on human neighbours and protect flying-foxes.

About bat camps
A bat camp (or roost) is a patch of trees where flying-foxes sleep during the day, raise their young, socialise, keep safe from predators and from where they fly out to feed each evening, up 20 km away. Some camps have been in use at least since the early days of European settlement.

Many camps are now located in urban areas, and are part of a great network of sites that allow flying-foxes to travel hundreds of kilometres across their range to access new food sources. Some camps are occupied most of the time; others are occupied only every few years when there is good food in the area.

Some flying-foxes stay in one camp for months or years (residents); others move rapidly through several camps, staying only briefly, until they arrive at a large eucalypt flowering (nomads).

There is a lot we don’t yet understand about how flying-foxes choose and use roost sites. Their use of urban locations may be driven by the following factors:

Some camps were established before they became part of suburbia.
Some became established after camps elsewhere were destroyed
Urban areas offer reliable food resources, and perhaps other advantages such as safety and easy navigation

Why don't flying-foxes go live in national parks, or out in the bush?
Flying-foxes camp near where there is food for them, whether it is urban or rural. With widespread loss of bushland, urban areas have become increasingly important to them.

Flying-foxes have lost much of their most productive habitat to farms and cities: two-thirds of the original vegetation of the coastal lowlands from the Sunshine Coast to the Gold Coast has been cleared; in some areas abutting the Great Divide, three-quarters has gone. Often it’s the least fertile areas (and less productive for flying-foxes) that were spared, some of which are now national parks.

Although they go nowhere near to making up for the loss of vast areas of nectar-rich woodlands, fertilised and watered urban gardens and parks can offer reliable food for flying-foxes.

Can't we get rid of them from urban areas?
There is no practical way of removing flying-foxes from most urban areas, and no need to for human health or safety. There is no disease that can be caught by walking or living near a bat camp or having them feed in your garden (see below).

Flying-foxes are loyal to their roost sites. They can be temporarily scared away from a camp but will almost inevitably return days or months later. They usually disperse to a location near the original camp, often in a more inconvenient location (backyards for example). If there is food in the area, they are unlikely to move far. Short of repeated disturbance, which is expensive and disruptive for human neighbours, or destruction of the roost site, there is no way of preventing their return.

It is illegal to disturb a bat camp unless it is authorised by the environment department after an assessment of likely impacts and alternative roost options. There are good reasons for regulating disturbance:

Dispersed flying-foxes are likely to roost nearby in often inconvenient locations, so creating a worse problem.
Bat camps are important to flying-foxes and disturbance may interrupt breeding or separate young from their mothers
Disturbance is inherently stressful for flying-foxes, and could increase the risk of Hendra virus spillover. (Dispersing a bat camp from an urban area won’t reduce the risk of Hendra virus transmission to humans because humans catch the infection from horses, not flying-foxes.)

Dispersals are mostly a waste of (ratepayers') money because of they vary rarely stop bats roosting in an urban areas. The Charters Towers council for example has spent more than half a million dollars over a decade of futile dispersal attempts.

It is often assumed that getting rid of bat camps is easy and simply requires more decisive action and forceful methods – “The Queensland opposition wants to use smoke bombs and choppers to evict urban bat colonies” (July 2011). But more forceful methods won’t prevent flying-foxes returning after disturbance has ceased. Even when flying-foxes used to be shot in camps (as they were in Charters Towers) they would return in subsequent years. Helicopters and smoke bombs are not a solution.

Are urban bats a health risk?

Some politicians have proposed the eviction of flying-foxes from urban areas (including by lethal force) on the grounds that they are a health risk. They "quote" risks such as Lyssavirus,Hendra virus, salmonella, leptispirosis and histoplasmosis. Yet apart from one case of Lyssavirus, there has been not one recorded case of any of the other risks mentioned being transmitted from flying-foxes to humans, and medical experts say that urban bat camps are not a health risk. Queensland Health states, “Flying foxes are not a health risk to you unless you are bitten or scratched.” Don't be taken in - learn the real facts here.

REFERENCES:References for the table can be found here. Major sources of data are:
(1) Australian Bureau of Statistics, Causes of Death, Australia (annual data available for the period 1990-2009 on the ABS website);
(2) Australian Bureau of Statistics, Year Book Australia, (annual data available for 1990-2009 on the ABS website). See http://www.abs.gov.au/
(3) National Coroners Information Service report into Deaths Involving Animals, May 2006. See www.ncis.org.au/web_pages/Broadsheet2_Animal%20related.pdf.
(4) National Coroners Information System. 2007. A sample of consumer product related deaths. Deaths reported from 01/07/2000–30/06/2007. See www.ncis.org.au/Product%20related%20fatalities%20national%20version.pdf.
(5) Pollock K, Fragar L, Morton C. 2007. Traumatic deaths in Australian agriculture – The facts. Rural Industries Research and Development Corporation and Australian Centre for Agricultural Health and Safety
(6) Franklin R, Mitchell R, Driscoll T, Fragar L. 2000. Farm-related fatalities in Australia, 1989-1992. Moree: ACAHS, NOHSC & RIRDC