Monday 22 January 2007

In the name of the Crow: human abuse

One example of an incongruent system sitting uncomfortably within a larger domain is the status of the Torresian Crow in Queensland, Australia, more particularly in the Brisbane metropolitan region.

These crows are a protected species because they are deemed to be indigenous and seen as a valuable player within the environment. Fines for killing the birds can reach up to A$225,000 or two years' jail. The official justification for their protection is based on the argument that the crows are scavengers which dispose of garbage and therefore contribute to a cleaner environment around the suburbs.

Over the years they have become an issue because of the loud noise they make. A single bird can produce up to 82 decibels, not far from the 85db considered to be harmful for humans under prolonged exposure. In more practical terms this means a crow 20m away from a window and cawing away makes it impossible to understand the other party on the phone. Naturally, there could be many more birds in nearby trees. In summer they begin their ruckus from about half past four in the morning onwards and so make sure humans within hearing distance get woken up regularly every day of the week. From then on during the ensuing daylight hours the noise can last for half an hour, one hour, or two hours etc depending on their whim. By the way, the decibel data come from Associate Professor Darryl Jones, Director of the Centre for Innovative Conservation Strategies at Griffith University, Brisbane, a staunch defender of the bird's current status.

The Torresian Crow occupies a region stretching from the tip of Cape York in Queensland down to northern New South Wales along the eastern seaboard (a north-south distance of nearly 3000km) and latitudinally right across the upper half of the continent to the coast of Western Australia, (details - you can even download its call there and test it out on yourself making sure the volume is up). Over the last ten years the numbers have increased dramatically in the greater Brisbane metropolitan area and a conservative estimate would put them at about 4-500,000. Therefore extinction is not exactly an issue.

Regarding their noise, although being woken up very now and then may not be that significant, having to endure this treatment day after day does affect the sleeping patterns of humans. Sleep deprivation has been identified as a form of torture by the United Nations and prolonged lack of sleep is considered detrimental to one's physical and mental well-being, comparable to illegal levels of alcohol in one's blood and even leading to psychotic states (details).

Let me state my personal interest in all this: I am one of those affected, but given their distribution across the Brisbane area there would be thousands of others in a similar situation (and no, as of now I haven't reached a psychotic state).

Furthermore, the Brisbane City Council issues several guidelines for noise levels that justify complaints. The maximum levels for inside the house are 20 to 30db, for daytime in a quiet residential street they are 35 to 45db, for a large busy office they are 50 to 60db, and for lawn mowers from 15m away they have been set at 70db - all well below the possible 82db from crows.

How then can an academic stand by his stance resulting in a situation that invited the label of torture by the UN and has been deemed leading to major pathological conditions by medical experts in the field? Or for that matter, how can a city council have a law against behaviour that goes against established standards when the culprits are human but actually enforces non-compliance through much more stringent legislation when even worse is committed by certain wildlife?

As to their assumed waste disposal function, what do cities do which have no crows, or what did Brisbane do before the numbers escalated? And in any case, in regions around the world where garbage is left for animals to deal with the state of hygiene overall is precarious precisely for that reason - exactly the opposite of the claims given to us by our local officials.

To answer these questions a letter each is sent to Professor Darryl Jones and the Lord Mayor of Brisbane, Campbell Newman, referring to the above.

It is rational to be concerned about the environment, but the movement has sprouted a form of religion. Without that idiosyncrasy the crow problem could have been dealt with by now.

Brisbane is by no means alone. Below are just a handful of links out of hundreds, if not thousands.

Towns try new ways to fight annual invasion

Many cities have tried poisoning or shooting the birds, prompting protests. Some are trying more humane methods this year.

New earplugs isolate specific noise

Continual exposure to more than 85 decibels may cause hearing loss; pain starts at about 130.

Singapore home to 100,000 crows

Singapore is under siege by a huge flock of crows that is causing noise problems in the city's many high-rise apartment blocks.

City looking into crow problem

Officials with the city have requested an investigation into possible ways to change the roosting patterns of crows in our area.

Japan Crow Observation Logs

Other great cities battle rats or pigeons. But the scourge of Tokyo is crows.

Nothing to CROW about yet!

Just poison them already....

The Crow Must Go

Although there are relatively large numbers of house crows in the Metro area (and further afield), it is still possible to control their numbers effectively, although at this stage total eradication would be preferred.

Blackbirds and Blackbird-like Birds

The main concern about crows is their huge roosts, especially when these roosts are located near residential areas.

Emotion and identification of environmental sounds and electroencephalographic activity.

Even when the loudness and frequency component of the sounds were equivalent, there was big difference in pleasantness-unpleasantness estimation among the environmental sounds.

Bird Control

They will literally overwhelm trees and buildings creating tremendous noise pollution while harassing both people and animals in the area.

Defeating decibels - noise pollution - Greenwatch

More than a third of the 400 million inhabitants of the OECD countries are exposed to a daily dose of 65 dB, an unacceptably high level; 200 million live in an uncomfortable sound environment.

Crows: A 'nuisance' but one smart creature

No single solution, including poisoning with the compound DRC-1339 (currently under consideration by the City of Terre Haute), has yet proven effective.


Common problems regarding crows include: noise; damage to gardens, agricultural crops and trash.

Ann Arbor crows return in time for the holidays.

The crows may not be dangerous, but they are annoying, says U-M pest specialist Dale Hodgson, who has worked with Parr on the crow problem in Ann Arbor for the last three years.

Controlling Crows

It seems you have learned first hand why the North American migratory bird act needs to be modified.

Dispersal of Blackbirds, Crows, and Starlings from Urban Roosts

# Odor, noise, filth # Droppings deface equipment # Damage to trees # Health concerns - Histoplasmosis:

Pest Bird Species Crows

When crows are in their flocking phase, thousands of these very noisy pest birds can literally overwhelm trees or buildings in an area, creating a tremendous amount of noise and harassing both people and animals in the area.

As the Crow Flies

They roost on power lines, foul the sidewalks with excrement and pollute the air with a loathsome, sleep-killing wall of noise.

Get rid of Crows?

i'll tell ya whatcha need some rat poinson and some garbage....problem solved


Frederick Pottinger said...

how about value-adding by coming up with a crow-call noise-cancelling device, presumably emitting an out-of-phase sample of the original crow call template?

you'll need a snappy name, cark-cancel perhaps?

John Brennan said...

I am a resident of yeronga Brisbane and crows are driving me to sometimes desperation specially when a "crow murder is taking place often with dozens of resident crows". Their victms can be a dove as happened last week.
Crows are less evident in the country and increasingly more evident in the cities where they are protected. Farmers keep their numbers down to balance their numbers against other bird species.
Numbers of other species of birds are obvious by their absence in our area of Yeronga in spite of the numerous trees and parks here.
Toads may be killed in the cities by smart crows but perhaps the arm chair greenies could trap city slicker crows, ship them to the NT and reduce the toad invasion up there!