This article was originally published by Simon Griffith on The Conversation, and shared as part of the Creative Commons.

For the past five years there has been a growing movement to recognise March 20 as World Sparrow Day – a day to celebrate the house sparrow (Passer domesticus) with art, poems, stories and events like office parties and school activities.

Let us convince you that this is an event that we too should take seriously and start celebrating here in Australia. It’s not too late to have an impromptu event or upload your support to the official website.

World Sparrow Day is an initiative of the Nature Forever Society, a conservation body established in India that aims to increase conservation action within urban areas.

In order to protect biodiversity throughout the world, there is a real challenge in getting increasingly urbanised populations to value the natural world. This Indian campaign is an excellent attempt to address this challenge.

The value of the house sparrow in Australia
People who interact with nature are more likely to conserve it. For many people these critical interactions are increasingly occurring within cities.

This has been termed the “pigeon paradox“, because for a large proportion of the population, conservation action may be dependant upon people’s interactions with non-native species in urban areas.

However, because native species are less likely to inhabit urban areas, we cannot afford to simply “write off“ interactions with non-native species.

By encouraging people to reflect on, and enjoy their local interactions with common urban species like the house sparrow, we can make them more likely to respect and value nature and biodiversity at a global scale.

The house sparrow’s global journey
The house sparrow is the perfect target for such a campaign. The house sparrow was one of the first animals that developed a very close association with humans as agriculture developed in the Middle East and people first began to create permanent settlements. Fossilised remains) of house sparrows have been found in the Middle East that are over 10,000 years old and from a Bronze Age long house in Sweden that is 3,000 years old.

Over the past few thousand years sparrows spread passively alongside humans as we expanded our range around the world. Within the past 150 years, this spread was actively facilitated by people as the house sparrow was deliberately introduced into the Americas, parts of Africa, and in Australia and New Zealand from 1863. As such, the house sparrow is now the most widespread urban bird in the world.

Sparrows were introduced to these areas to help control agricultural and horticultural pests in these new regions, and it was believed they would remain mostly inside the colonies.

There are anecdotal reports from Australia that they were even enthusiastically welcomed by newly arrived immigrants from Europe as a reminder of home, with the gentle chirruping of the sparrow around the homestead being a welcome relief from the “screeching Australian birds”.

As initially suspected, it is indeed true that sparrows today are essentially restricted to the areas where people are, and there are no indications that they have adversely affected any native species.

Pest species or opportunity?
Over the past year we have been conducting research into house sparrows in Australia, trying to gain insight into how introduced species become established and have adapted so well to new environments.

In the course of our travels, we have met many generous people who have given us access to the birds that frequent their back yards, feed alongside their chickens or horses, or come to visit them at smoko, or in the café to be fed on crumbs or left-overs.

While some people have bemoaned the sparrow as a feral introduced pest, overwhelming we have found Australians – from Townsville to Hobart, and Sydney to Coober Pedy – enjoy the company of this little brown bird.

Countless people have told us stories of their earliest childhood experiences of interacting with nature being with sparrows. Most people can remember having them around when they were growing up, and in many areas people have commented on how they miss them, now that they no longer seem to be around in the same numbers.

A bird in global decline
This brings us to the second important point underlying World Sparrow Day. Over the past 40 years, the house sparrow has suffered a spectacular decline in numbers across the world. Numbers have dropped by over 50% in the UK alone since the 1970s.

The cause of this decline remains a mystery. There is even a £5,000 (~A$9,600) prize by the UK Independent newspaper for a scientific explanation which remains unclaimed after fifteen years.
This is a cause for concern, because for a species that lives so closely alongside people in the urban environment, it provides a stark demonstration of the way that we are degrading the world.

If sparrows can’t prosper in our modern world, then whatever is causing problems for them is likely posing a risk to us. Agricultural chemicals, lead pollution or the chemicals that now replace lead in petrol, and mobile phones have all been touted as possible explanations of the decline of the sparrow.

While the exact cause of the decline – which is the focus of some of our work in Australia – is an interesting question, we should embrace the idea of celebrating the house sparrow now.

We should value this bird for what it can tell us about the state of the world we live in, and celebrate the fact that this is a wild animal that most Australians (and indeed people around the world) can interact with on a daily basis, and which can brighten up our lives.

Keep doing your bit for our threatened native species, but spare a thought for this urban battler. Maybe throw one a few crumbs, or put out some water or even a nest box.

If all that is a bit much, then at least express your support for this smart Indian campaign by visiting their site or supporting it through social media.

Catch up on recent contributions to The Conversation from other Macquarie authors.