Flying foxes are smelly, noisy, quarrelsome and crap all over white cars. They are also some of the most sociable, complex and graceful wildlife to be encountered in urban environments.
Flying fox camps are usually located in stands of tall trees rather than in large areas of continuous forest. Separation from surrounding vegetation makes it easier to see approaching predators. A common location for flying fox camps is trees next to rivers or wetlands. Another situation that attracts them is large ornamental trees, which unfortunately are often associated with schools, hospitals or nursing homes.
The Parramatta Park colony of Grey Headed Flying Foxes in western Sydney combines both situations, with the camp in a stand of trees next to the river and adjacent to a hospital. Although the bats sleep in the day there is a constant undercurrent of squabbling and jockeying for prime positions. This results in flights across the river, which makes it very easy to photograph the bats. An afternoon meeting in Parramatta saw my lunchtime spent wandering through the camp.
The colony was more restless than usual, fanning themselves in the unseasonal heat and getting spooked by arborists trimming nearby trees. Over the course of half an hour just about every flying fox in the camp took to the wing at some point, jostling their way through the crowded air space over the river.
Grey Headed Flying Foxes are quite variable in colour. Some have grizzled grey hair all over their heads and down to red collars around their necks, while others are much darker. Amongst the wheeling bats a few looked even darker than usual, and as they settled I realised that the ‘dark’ bats were all concentrated on a single tree. Closer inspection revealed that they were a different species, the Black Flying Fox. It was the first time I’d seen the species in Sydney.
Two Black Flying Fox had colour bands on their wing fingers. A few moments on google revealed that bats in the Royal Botanic Gardens were banded prior to being driven away from the site a few years ago. A few Black Flying Fox had arrived in the Royal Botanic Gardens back in the mid 2000s, initially just over summer before becoming year round residents from around 2010. I couldn’t find any other reference to a local banding program so it seems likely they picked up the jewellery in the CBD.
Black Flying Foxes are a tropical species that was only recorded north of the Queensland border prior to the 1960s. The species has been working its way down the coast even since, and has recently been recorded in camps as far south as Melbourne.
It is not uncommon to find tropical wildlife around Sydney. Tropical fish are especially common. The baby fish get caught in south flowing currents as fry, settling on the Sydney coast and growing through the warm summer and autumn months. Most die over winter, and those that survive the cold don’t have the right conditions to establish breeding populations. During this week’s night dive at Shiprock Aquatic Reserve I saw several of these tropical vagrants, including Highfin Moray, Stars and Stripes Pufferfish and Schooling Bannerfish.
Migratory birds have a different pattern as they move south, several species breeding in Sydney before heading back north with their offspring to avoid the winter. It’s obviously easier to fly north than to swim!
The expanding distribution of Black Flying Foxes isn’t one of these seasonal patterns, but rather a genuine change in the range of the species. They were first recorded breeding in Sydney only a couple of years after first arrival, and between further southern migrations and local breeding their numbers are expected to continue to increase. It’s thought that forest clearance in southeastern Queensland may be playing a role, although increasing winter temperatures are increasing their ability to survive down south.
I have no doubt that anthropogenic climate change is real and really here. As a consequence we will increasingly find wildlife species from northern Australia establishing around Sydney. The one thread of comfort I find in global warming is that changing species distributions are evidence that wildlife can, at least in some circumstances, respond to climate change. This is far from the only time our planet has undergone large scale climatic change. Species respond to such changing conditions, whether a glaciation or warming event, by shifting distributions. The challenge will be whether we are prepared to accommodate such wildlife as they move into ‘our’ environment, irrespective of their smelly, noisy or quarrelsome habits.
Odds and sods