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Urban Birds: The Mulch Mover

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

Metropolitan Adelaide, like other Australian cities, is a multicultural haven for birds. In addition to the more than 200 native bird species that can still be found in the region, Metropolitan Adelaide is also home to many alien and exotic bird species. The alien species are birds that have spread to Metropolitan Adelaide from elsewhere in Australia since European settlement due to the creation of new habitats by urbanisation. The exotic species are birds that have been introduced to Australia from overseas.

Male Blackbird


Figure A: Male Blackbird by Ry Beaver

An exotic species that has become one of the 30 most common birds inhabiting Adelaide’s urban parks and gardens is the Common Blackbird (Turdus merula). Early settlers deliberately released Blackbirds imported from Europe at several locations in south-eastern Australia during the 1850s and 1860s, hoping they would help to control agricultural pests. Initially, these introductions were only successful in establishing Blackbird populations in Melbourne and Adelaide, but the species has since spread throughout south-eastern Australia, as far north as Sydney and as far south as Tasmania, via the Bass Strait Islands.

The male (Figure A) is the ‘black bird’ for which the species is named. He is coal black, with a deep orange to yellow bill, a narrow yellow eye-ring and dark legs. She is sooty brown, with a dull yellowish-brown bill, a pale throat and a weakly mottled breast (Figure B). Both sexes are small birds measuring about 26 cm in length from bill tip to the end of the long tail.

Blackbirds feed largely on the ground, foraging in litter for worms, snails, insects and spiders. They can be mistaken for rats as they make a quick run through the undergrowth, followed by an abrupt stop to toss litter aside with rapid bill flicks. This method of feeding does not endear the Blackbird to water-wise gardeners who find their mulch repeatedly scattered across lawns and paths.

Female Blackbird


Figure B: Female Blackbird by Museums Victoria

During the Spring nesting season, males and females engage in fierce territorial battles with rival Blackbirds, sometimes locking claws and wrestling on the ground. Because of their territoriality, if you have Blackbirds in your garden, they are likely to be a mated pairs, with one pair patrolling your front garden and a second pair claiming your backyard.

Citizen Scientists have made significant contributions to our knowledge of urban birds by participating in the annual Aussie Backyard Bird Count. In 2016, South Australians reported sightings of 76,677 individual birds, with Blackbirds being recorded more frequently than during previous counts. In 2017, the Aussie Backyard Bird Count will be held from 23 till 29 October during National Bird Week. If you would like to record the birds in your garden, you can register online to participate in the count. The online Birds in Backyards Bird Finder is a useful aid for identifying common urban birds, if you feel the need to practice before the count.

Resources

Posted in Nature Notes

Cloud Spotting

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

People who made their living from the land or the sea once used cloud rhymes to predict sunshine and rain.

Mares’ tails and mackerel scales make lofty ships carry low sails.

When clouds appear like rocks and towers, the earth’s refreshed with frequent showers.

Clouds remained an important predictor of weather during the development of the science of meteorology in the early 1800s. This inspired Luke Howard, a keen observer of the weather in and around the city of London, to propose a classification of clouds in 1802. He recognised three main types of clouds: Cumulus (rocks and towers), Cirrus (mares’ tails) and Stratus, as well as combined types like cirrocumulus (mackerel sky).

Howard’s classification formed the basis for the modern system of classifying clouds into 10 types by shape and height above the earth (as shown in the diagram below).

Cloud Types


Cloud Classification by Valentine de Bruyn (2012)

  • Cirrus: A high cloud with white tufts made from ice crystals. Prediction: no rain.
  • Cirrocumulus: A high cloud with small ripples made from ice crystals. Prediction: no rain.
  • Cirrostratus: A high cloud that looks like a transparent veil. Prediction: no rain.
  • Altocumulus: A mid-level cloud, white and rippled with dark shading. Prediction: possible light showers.
  • Altostratus: A mid-level cloud that looks like a grey sheet and allows the sun to appear as if shining through ground glass. Prediction: rain or snow.
  • Nimbostratus: A thicker and darker sheet of low cloud. Prediction: heavy rain or snow.
  • Stratocumulus: A low cloud that looks like a series of white rolls. Prediction: drizzle.
  • Stratus: A low grey cloud with a uniform base. Prediction: drizzle.
  • Cumulus: Low clouds that appear as separate vertical rolls or towers. Prediction: rain showers.
  • Cumulonimbus: Large cauliflower-shaped towers, often with ‘anvil’ tops, that sit low in the sky. Prediction: rain showers or snow.

Now that they are equipped with a wide range of scientific instruments for measuring atmospheric conditions, meteorologists no longer rely on cloud observations to aid weather prediction. However, the publication of “The Cloud Spotter’s Guide” in 2006 encouraged the appreciation of clouds as objects of natural beauty and wonder. Cloud spotting became a new hobby and the formation of a Cloud Appreciation Society soon followed, with more than 40,000 members now sharing images of particularly beautiful or unusual cloud formations online. Of course, there is an iPhone and Android app, but for many cloud spotters it is enough simply to look up at the sky every now and then and marvel at the view.

The Coton Cloud Identification App is available at:

  • iTunes:
Coton
Developer: Etamin Studio
Price: $1.99
  • Google Play:
Coton
Developer: Etamin Studio
Price: $2.49

 

Resources

Posted in Nature Notes

Under the Mistletoe

Mistletoe in trees in Adelaide

Mistletoe in trees in Adelaide

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

The word ‘mistletoe’ refers to many different woody plant species that have the same life form.  The distinguishing features of the mistletoe life form, in addition to a woody stem and branches, are evergreen leaves and, especially, the mistletoe’s unusual method of obtaining moisture and mineral nutrients.  Trees and most other woody plants have roots that anchor them in the soil and absorb moisture and mineral nutrients from the soil.  In contrast, a mistletoe’s stem is anchored to a branch in the canopy of a tree by a structure called a haustorium that sends root-like filaments into the branch in order to absorb moisture and mineral nutrients from the host tree’s sap.  Because the mistletoe’s evergreen leaves allow it to manufacture its own organic nutrients by photosynthesis, mistletoes are classed as half parasites (hemiparasites), unlike wholly parasitic plants (holoparasites) that obtain all their nutritional needs from their host.

In ancient Britain, the first plant to be called ‘mistletoe’ (Viscum album) was used in winter solstice ceremonies because of its seemingly miraculous ability to remain green and produce fruit during the season when the host trees shed their leaves and become dormant.  At Christmas, in Europe and North America, it is still customary to kiss for luck under a sprig of mistletoe.

Many Australians regard mistletoe as an exotic plant introduced from overseas and damaging to Australia’s native ecosystems.  In fact, all of the 91 species of mistletoe that occur in Australia are native, and mistletoe is increasingly being recognised as a keystone component of Australia’s biodiversity because it provides food and shelter for a wide variety of native animal species, from possums, to birds and butterflies.

In Metropolitan Adelaide, the Harlequin Mistletoe (Lysiana exocarpi) has spread from its native hosts (mainly Acacia, Allocasuarina, Cassia, Eremophila and Santalum species) to exotic street trees and ornamental garden plants, including Citrus, Jacaranda, Lagerstroemia (Crepe Myrtle), Magnolia, Nerium (Oleander), Platanus (Plane Tree), Prunus, Quercus (Oak), Salix (Willow) and Schinus (Pepper Tree) species.

Winter and early Spring are the best times to spot mistletoes on exotic hosts that have shed their leaves at these times of year.  You can contribute to our understanding of the distribution of mistletoes in Metropolitan Adelaide and other cities and share your sightings with other mistletoe spotters by posting your digital images and locational information on the BowerBird website.  If you can identify the species of the mistletoe and its host, that would be a bonus.

Resources

BowerBird:a Place to Share and Discuss Australia’s Biodiversity (www.bowerbird.org.au/). A project has been set up for Mistletoe in Cities at: http://www.bowerbird.org.au/projects/10497

Watson, D 2001, Mistletoes of Southern Australia, CSIRO Publishing, Collingwood VIC.

Posted in Nature Notes

Sounds of the City

Red Eye Cicada

A Red Eye Cicada (Psaltoda moerens), a familiar sound in south eastern Australia. Photo courtesy of Peter Ermel (CC), who posted this cicada record on the Atlas of Living Australia

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

One aspect of the current worldwide decline in biodiversity that goes largely unnoticed is the loss of singers, in what Bernie Krause calls ‘the great animal orchestra’ of wild places, as one animal voice after another falls silent and is replaced by the sounds of human activity.

In the city, the human orchestra dominates the urban soundscape, but if you listen closely, you can still hear the voices of wild animals. The most familiar are bird calls, but many insects, particularly crickets and cicadas are surprisingly loud singers.

The Black Field Cricket (Teleogryllus commodus) is found throughout Australia and has adapted to living in even the most urbanised parts of our cities where it is rarely seen, but frequently heard at night, from spring to autumn, singing in stormwater drains and culverts. Only the males sing to attract mates, producing complex high pitched calling and courtship songs by rubbing their wings together (called stridulation). Females are more likely to mate with strong males that can sing loud sustained songs. Hear an audio recording of a Black Field Cricket on the Encyclopedia of Life website at: http://eol.org/data_objects/23626483.

Most people in south eastern Australia are more familiar with the song of the Red Eye Cicada (Psaltoda moerens) than that of the Black Field Cricket, as the Red Eye’s loud singing, among the loudest of any insect, can dominate the suburban soundscape on hot summer days and nights. Again it is only the male Red Eye that sings, producing a two-part song consisting of several revving sounds, followed by a rattling continuous sound.

Unlike crickets, cicadas don’t produce sound by rubbing their wings together. Instead, a cicada has a special noisemaker (called a tymbal) on either side of its body. Each tymbal resembles a kettle drum and consists of a membrane stretched over a space in the gut that acts as a resonating chamber. Continuous sound is produced by rapidly vibrating the membrane and modulated to produce the revving sounds by flexing the body up and down. Hear an audio recording of a Red Eye Cicadas on the Atlas of Living Australia website at: http://bie.ala.org.au/species/Psaltoda+moerens.

The Red Eye is a relatively large insect about 12 cm long and can be found feeding on the sap of Eucalyptus and Angophora trees in bushland and a variety of native and introduced trees in suburban parks and gardens. Even when it occurs in very large numbers, as it does in some years, the Red Eye is not considered to be a pest. It does not bite and is harmless to the children who often capture a Red Eye and keep it for a day or two of close observation in a box with a few leaves.

In Australia, children were the first to coin common names for many of the more than 200 species of cicada inhabiting our continent, names that have been passed down from generation to generation of cicada hunters. In addition to the Red Eye, some of the more descriptive names are the Black Prince (Psaltoda plaga), Green Grocer (Cyclochila australasiae), Double Drummer (Thopha saccata), Cherry Nose (Macrotristria angularis) and Floury Baker (Aleeta curvicosta).

Today, cicadas and other interesting insects can be captured on smart phones. You can share your discoveries with other insect hunters, including scientists who study Australia’s biodiversity, by posting your digital images, videos and sound files on the BowerBird website. Check it out!

Resource
BowerBird: a Place to Share and Discuss Australia’s Biodiversity (www.bowerbird.org.au/). Learn about BowerBird in a Discovery Circle blog (click here).

Krause, B 2012, The Great Animal Orchestra: Finding the Origins of Music in the World’s Wild Places, Profile Books Limited, London UK.

Posted in Nature Notes

It’s Spring. Beware!

Eastern Brown Snake

An Eastern Brown Snake (Pseudonaja textilis). The Eastern Brown Snake is one of Australia’s most dangerous animals. Photo courtesy of Peter Clark (CC BY-NC-SA 2.0)

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

If you were asked to identify the most dangerous animal in Metropolitan Adelaide, you would probably name the Eastern Brown Snake. People frequently encounter this fast moving and aggressive snake in spring when it wakes from its winter hibernation and begins searching for food and a mate. Because its venom is ranked as the second most toxic among the world’s land snakes and because it is common even in urban areas, the Eastern Brown Snake and other related brown snakes are responsible for more deaths every year in Australia than any other group of snakes.

The Australian Museum has assigned Australia’s most dangerous animals a rating of 1 to 10 based on their threat to human health and the likelihood of their interaction with people. The Eastern Brown Snake has a danger rating of 8/10, but an even more dangerous animal becomes active in urban areas during the spring. With a rating of 9/10, the European Honey Bee is the most dangerous land animal in Australia. It is extremely common in urban areas and its sting frequently causes life-threatening allergic reactions (anaphylaxis) in susceptible people.

Spring means gardening and encounters with creepy crawlies in the undergrowth. In Metropolitan Adelaide we needn’t fear Sydney’s deadly Funnel-web Spider (8/10), but Redback Spiders (6/10) are now found more commonly in urban houses, outbuildings and gardens than they are in native bushland. Fortunately, Redbacks are shy and secretive spiders. The majority of bites occur when a mature female spider is accidentally trapped against the palm of the hand or the seat of the pants, as garden furniture is a favourite habitat. Other gardening menaces that often cause painful and, more rarely, life-threatening bites are the Bull Ant and Giant Centipede, both with a danger rating of 5/10.

Although it rarely causes a life-threatening injury, the urban animal most likely to be involved in a potentially serious injurious interaction with humans is the Australian Magpie. Every spring, breeding Magpies swoop down from their nesting trees to attack people walking or cycling below. Only some Magpies (almost always males) aggressively defend their nests, but Magpies nest in almost all urban habitats and repeated attacks over several months by even a minority of birds have earned this species a place on the Australian Museum’s list of Dangerous Australians.

Resource

Australian Geographic Magazine (2013), Australia’s Dangerous Animals: The Top 30

Posted in Nature Notes

Rakali

Rakali

A Rakali, or water-rat (Hydromys chrysogaster). The Rakali is one of Australia’s largest native rodents. Photo courtesy of 0ystercatcher/flickr (CC BY-NC-SA 2.0)

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

Australia has more than 60 species of native rodents that, until the 1990s, were generally called ‘rats’ and ‘mice’. Unfortunately, these European names for rodents are associated with disease and filth. This has tended to discourage public concern for our native rodents. Words from Aboriginal language groups are now more commonly used as native rodent names, a welcome change for these important representatives of Australia’s unique wildlife.

The area that is now Metropolitan Adelaide was once inhabited by five species of native rodent. The Parroo and Pankot (White-footed Rabbit-rat and Mitchell’s Hopping Mouse) are now extinct in the region. Urbanisation has greatly reduced the amount of habitat suitable for the Mootit (Bush Rat) and the Koota (Swamp Rat), but both these native rodents can be found on the outskirts of Metropolitan Adelaide. The Mootit occurs in vegetation with a dense understorey on the footslopes of the Mt Lofty Ranges (see Nature Note 1), while the Koota inhabits areas of low shrubland near wetlands and streams on the Fleurieu Peninsula.

In contrast, the Rakali (Water Rat) is an urban survivor and has even adapted to life in downtown Adelaide where it inhabits the River Torrens. The Rakali is one of Australia’s largest native rodents, measuring about 50 cm from nose tip to tail tip. During the day, the Rakali shelters in a burrow in a stream bank fringed with reeds and adjacent to a deep pool of slow moving water. The Rakali emerges from its burrow at dusk to swim and dive, propelled by its webbed feet, in the hunt for mussels, snails, yabbies, fish and frogs. When the hunt is successful, the Rakali often carries its prey to a rock, a log or a bridge footing surrounded by water before eating.

A good place to see the Rakali is in the River Torrens opposite the Adelaide Zoo. Look for the V-shaped wake created by a Rakali as its head moves swiftly through the water followed by the white tipped tail that is this native rodent’s most distinctive characteristic. If you do spot a Rakali, wherever you are, you can contribute to the conservation of this species by reporting your sighting. If you are able to get a photograph or video, you can submit these sightings online to Bowerbird. You can also report sightings to the Australian Platypus Conservancy, an organisation that records observations of both the Platypus and Rakali.

Resource
Bowerbird – read the Discovery Circle blog about Bowerbird: click here
Australian Platypus Conservancy: http://www.platypus.asn.au/

Posted in Nature Notes

Strangers in a Strange Land

Eastern quoll

An Eastern quoll (Dasyurus viverrinus). These cat-sized native carnivores are now considered extinct in the Adelaide region. Photo courtesy of nuytsia/flickr (CC BY-NC-SA 2.0)

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

When European settlers first arrived in Australia, almost everything about this continent was strange to them.  They did not understand the languages and customs of the Aboriginal people they encountered.  They did not know the names of the native plants and animals inhabiting the vegetation they cleared to establish their towns and farms.  In South Australia, even the semi-arid climate of the settled districts, with its boom and bust years and intermittent stream flow, presented the new arrivals with unfamiliar challenges.  But they had spent months at sea and travelled halfway around the world to get here, knowing there was little chance of going back, so they set out to make Australia home.

One indicator of an emerging Australian identity has been the increasingly widespread acceptance, among scientists and the general public, of Aboriginal words as common names for our native mammals.  The egg-laying mammals (monotremes) seem to be stuck with the Latin and Greek derived common names (‘platypus’ and ‘echidna’) they were given by European scientists in the late 1700s.  However, the pouched mammals (marsupials) have fared better; so we have ‘kangaroo’, ‘wallaby’, ‘wombat’ and ‘quoll’ derived from Aboriginal words during the early years of settlement and ‘dunnart’, ‘mala’ and ‘bilby’ as examples of Aboriginal names for marsupials that have come into general use as common names since the 1920s.

Unfortunately, most Australians still know our third most numerous group of native mammals (after the marsupials and bats) as ‘rats’ and ‘mice’, names that reflect their resemblance to the European rodents that were introduced to Australia and have become vermin here.  The area that is now Metropolitan Adelaide was once inhabited by five species of native rodent, and three of these species have survived the urbanization process.  Next month’s Nature Note will introduce you to one of these survivors by the Aboriginal common name it has recently been given, ‘rakali’.

Resource

Atlas of Living Australia, http://www.ala.org.au/

Posted in Nature Notes

Wetland Music

Southern brown tree frog (Litoria ewingi) Image courtesy of Steve Walker

Southern brown tree frog (Litoria ewingi)
Image courtesy of Steve Walker

Discover Your Patch: Adelaide Nature Notes by Dr Sandra Taylor

In 1990, the City of Salisbury established Greenfields Wetland, one of the first large, constructed urban wetlands in Australia.  There are now more than 50 constructed wetlands in Salisbury, and several other city councils in Metropolitan Adelaide have constructed wetlands; notably Oaklands Wetland in Marion, Urrbrae Wetland in Mitcham and First Creek Wetland in the Adelaide Botanic Garden.

The term ‘constructed wetland’ is technically correct, but increasingly inaccurate as the wetland ages.  Bulldozers shape the wetland topography; the wetland ponds are flooded with storm water; tree and shrub seedlings are established on the wetland ridges and reeds, rushes and sedges are planted in the wetland shallows.  Then the council workers leave, and natural processes begin to transform this constructed place into a wild place.

Winds bring flying insects and the seeds of new plants to the wetland.  Birds arrive, followed by snakes, lizards and crawling insects.  Water birds carry plant and animal material on their feathers and in the mud between their toes.  The animal hitch hikers are mainly tiny aquatic critters (macroinvertebrates) such as insect larva, worms, snails and shrimp, but fish eggs and frog spawn can survive surprisingly long flights between water bodies.

With the hatching of frogs, the wetland finds its voice.  Of course there are the sounds of wind in the reeds, moving water and bird calls, but nothing says ‘freshwater wetland’ louder and more clearly than an all-male choir of frogs singing love songs.

Common froglet (Crinia signifera) Image courtesy of Steve Walker

Common froglet (Crinia signifera)
Image courtesy of Steve Walker

Take a guided tour of Greenfields or Oaklands Wetland and listen for the high pitched ‘weep-eep-eep’ of the Brown Tree Frog and the rapid ‘crick-crick-crick’ of the Common Froglet.  You may even hear a chorus of Banjo Frogs singing ‘pobblebonk’, the sound that gives this frog its common name.

Resources

Distribution maps and audio recordings of frogs found in Adelaide are available from: Natural Resources: Adelaide and Mt Lofty

Daniels, CB 2010, Adelaide: Water of a City, University of South Australia, Adelaide SA.

 

Posted in Nature Notes

Discover your Patch

Adelaide's major environments

Adelaide’s major environments
Image courtesy of Sandra Taylor

Adelaide Nature Notes by Dr Sandra Taylor

Introduction: A Sense of Place

People who live in rural and remote parts of Australia generally have a strong sense of place. They know the landscape they inhabit in a personal way that involves understanding, perception and memory of its natural processes. Wallace Stegner describes this kind of knowing as a deep relationship with the nature of a place that ‘comes from working in it in all weathers, making a living from it, suffering from its catastrophes, loving its mornings or evenings or hot noons’.

People who live in cities, like the majority of Australians, can have a strong sense of place if their neighbourhood has a distinctive culture reflected by its streetscapes and community activities. Unfortunately, contemporary patterns of Australian urban development and suburban growth tend to inhibit the creation of such neighbourhoods. An alternative way to nurture a sense of place in the city is to discover your neighbourhood’s natural environment. There are plants, animals, weather patterns and many other natural features that make your patch of nearby nature unique.

This series of Nature Notes will highlight aspects of Adelaide’s urban nature that may have caused you to wonder, ‘what is that?’. The notes are intended to help you understand the nature of your patch. Understanding, however, is only part of a sense of place; experiencing is also essential, so consider participating in one of our Discovery Circle Citizen Science projects or BioBlitz events.

Resource

Stegner, Wallace, 1993, ‘The sense of place’, in Where the Bluebird Sings to the Lemonade Springs: Living and Writing in the West, Penguin NY, pp. 199–206.

 

Posted in Nature Notes