Ecology

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<img src="https://counter.theconversation.edu.au/content/65629/count.gif" alt="The Conversation" width="1" height="1">
GUEST OBSERVER
Bird baths are a familiar sight in Australian gardens but surprisingly little is known about the precise role they play in the lives of birds.
In a dry continent such as Australia, bird baths may be vital to supporting an otherwise stressed bird population. We wanted to find out more, so we enlisted the help of thousands of citizen scientists across Australia to gather as much data as we could on how birds use bird baths. 
And so the Bathing Birds Study was born. Started by researchers at Deakin University and Griffith University in 2014, this study involved collecting data online from 2,500 citizen scientists on bathing birds all over Australia.
The study has revealed so far that bird baths are much more than just ornamental splash pools for feathered visitors. They’re also a site where animals socialise and intense rivalries play out. Human choices – such as the design of the bird bath, where it is located and how often it is cleaned – can have a big impact on birds.
<h2>Different baths for different birds</h2>
The majority of participants in the Bathing Birds Study monitored the traditional pedestal or elevated bath type.
Cats are a big risk to garden birds, so elevated or pedestal baths are a good idea. They help keep birds safe from cats.
Baths should be situated near plants so smaller birds can have refuge if they are disturbed. Stones or rocks in the centre of the bath can give smaller birds a place to perch while bathing. 
Birds need to groom their feathers daily, so don’t assume they’re only visiting bird baths on hot summer days. Birds need baths in winter too. We even had reports from some of our citizen scientists of birds trying to break ice in baths to access the water.
It can take time for birds to find a new water source but they will find it. Other types of baths, such as pots or saucers on the ground, can provide water for a range of wildlife species. We had records of koalas, foxes, snakes and even echidnas using baths – so consider having multiple types of water baths in your garden. 
<h2>Bath bullies</h2>
The Bathing Birds Study found that different bird species dominated bird baths depending on state or region. 
In South East Queensland and New South Wales, aggressive noisy miners and rainbow lorikeets were most frequently recorded at baths. Introduced birds and wattlebirds were more common in the cooler states of Victoria, South Australia and Tasmania.
The Bathing Bird Study also found that certain birds can act as bullies at baths and prevent other birds from using it by standing guard.
This type of behaviour can be directed toward smaller and/or less aggressive birds so having a range of bath types (such as a pot or saucer on the ground, hanging bath or multiple elevated baths) in your garden will give all birds a place to drink and bathe. 
<h2>A clean bath is a good bath</h2>
Like all bathrooms, the garden bird bath needs regular cleaning. A dirty bath can spread disease and birds can be susceptible to infection where many species and individuals are congregated at communal watering stations.
For example, infected parrots can spread beak and feather disease to other parrots when they bathe and drink together. 
Another risk is that birds will, in time, grow too dependent on bird baths or feeding stations. How might they cope if the food and water is withdrawn during certain periods or not adjusted to reflect the prevailing need of birds?
The Bathing Birds Study also showed that many people refilled their bird baths more frequently in summer than in winter and regularly clean the baths.
<h2>Is feeding birds good or bad? Let’s find out!</h2>
Many people enjoy providing food for birds as well as water. At this stage, we do not know whether this has a positive or negative effect on birds.
It is important to understand the ecological and behavioural effects of feeding in Australia as almost all information from other countries regarding bird feeding simply does not apply here. 
Feeding of wild birds is an important activity for large numbers of people. For many, it is a significant way of connecting with nature. 
The Australian Bird Feeding and Watering Study, an extension of the Bathing Birds Study, aims to find out more about how exactly birds interact with feeders and bird baths – and how human choices can either help or hinder these feathered visitors. 
We’ve just completed the winter stage of our research, which involved collecting responses online from 3,500 citizen scientist participants. Nearly 7,000 have signed up to take part in the feeding study so far, and we are now recruiting for the summer stage. If you provide food or water for birds and would like to get involved in the summer study, sign up at www.feedingbirds.org.au. 
We hope to one day develop guidelines for people who feed and/or provide water for birds so they can do so with minimum risk to the birds.
Grainne Cleary is researcher, School of Life and Environmental Sciences, Deakin University and author for The Conversation. She can be contacted <a href="https://theconversation.com/profiles/grainne-cleary-300485" target="_blank">here</a>.
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Bath bullies, bacteria and battlegrounds: the secret world of bird baths

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<img src="https://counter.theconversation.edu.au/content/65226/count.gif" alt="The Conversation" width="1" height="1">
GUEST OBSERVER
Whether you live in an urban apartment or a rural homestead, your outdoor area is more than just a private space. Ecologically, a garden is another jigsaw piece in the landscape. 
Whatever their size, gardens can contribute to natural functions and processes in the local area, such as regulating water drainage, buffering the damaging effects of strong winds, or providing food and shelter for native wildlife. 
Many wildlife species survive in urban areas, but their presence and persistence depend on how specific their food and shelter needs are, how they respond to disturbances, and the quality and quantity of other green spaces in the landscape. 
For larger animals, such as birds and mammals, a home garden could become a stepping stone across an otherwise hostile urban landscape. For smaller animals, such as insects, it could be the centre of their home range.
In urban areas, where space is often limited, gardening with pollinatorsin mind is a simple way to encourage biodiversity in the backyard. And, depending on the surrounding landscape, habitat for pollinators will also be habitat for other animals.
<h2>Flowers are just the first step</h2>
Flowers produce sugar (nectar) and protein (pollen), the main diet for many adult insects and birds. Unlike other insect groups, native beelarvae develop almost exclusively on pollen collected by their parents, so flowers are essential to grow native bee populations.
There is no single best combination of flowers for wild bees. Many “plants for pollinators” lists available online are based on local experiences and rarely apply to all geographic regions. A general rule of thumb for a pollinator garden is one that produces flowers for most of the year and is built on diversity – monocultures of any single flower type or colour will suit only a very small number of generalist species.
Native plants are an ideal option for attracting native pollinator insects and birds, but many garden exotics, especially herbs, fruit and vegetable plants, are just as popular. Modern hybrid varieties should be chosen carefully, as some are bred for commercial fruit or flower traits (like size or colour), but the flowers lack the nectar or scent cues that attract pollinators looking for food. 
<h2>Build it and they will come</h2>
The structure and design of a garden can determine what wildlife species will visit or make a home. Vertical structure, built from multiple layers of different plant heights, provides more spaces for wildlife to co-exist. Small plants and shrubs provide good shelter for insects and very small birds, while larger trees will attract visits from more mobile birds and mammals. 
Large trees with rough or shedding bark that creates lots of cracks and crevices are excellent shelter for insects and small lizards. Trees that produce resins and sap flows, such as conifers, acacias and eucalypts, are also useful for some native bee and wasp species that use resin to seal their nest cells. 
Insect hotels can provide homes for insects that usually nest in dead wood. But only a small proportion of the world’s bee species are wood-nesters. About 75% of bee species dig their nests into the ground, usually in sandy, uncompacted soil, preferably on a slope that won’t get waterlogged. 
It can be difficult to build all of this into small gardens, but many pollinator insects will have home ranges of a few hundred metres, while birds and mammals can travel much further. So landscape composition can also influence the wildlife potential of an individual garden. A high proportion of paved areas can reduce the number of wild bees or native birds in the neighbourhood. Highly manicured green spaces can also have a negative effect on wild bee species. 
<h2>Disrupting the food chain</h2>
Like any ecosystem, gardens involve an intricate web of life, from the soil microbes underground to the birds in the trees. It’s easy to grab the spray bottle to kill off the dandelions and blow down the flies, but what are the knock-on effects?
Many of the animals and plants we think of as a backyard nuisance often provide services we don’t see. For example, many native wasp and fly species (even blowflies!) are pollinators as adults. And as larvae, they control many of the insect pests we see on our plants, or decompose organic wastes. Small reptiles, like geckoes and skinks, mostly feed on small insects that annoy us, like mosquitoes and midges.
Plants we think of as lawn weeds, particularly dandelions and clover, are a favourite food source for native bees and hoverflies. Aphids and scale insects also produce a sugary substance called honeydew as they suck on plants, which is an important sugar source for some beneficial insects like wasps, bees, ants and hoverflies. 
Limiting synthetic chemical use is one of the easiest and cheapest ways to enhance wildlife in gardens. Insecticides can kill beneficial insects, or affect them indirectly by disrupting their metabolism or reproductive cycles. Overuse of herbicides removes important food resources, like dandelions, that pollinators rely on if other flowers are scarce. 
There is also the potential for chemicals to work in combination and have a greater impact.
<h2>Managing gardens as ecosystems</h2>
Many wildlife don’t like regular disturbances, which is why urban areas can be intimidating environments for animals. It can be hard to balance human needs with the habitat needs of wildlife. Many actions that minimise risks for humans can have the opposite effect for wildlife. 
For example, pollinators generally prefer open grassy areas to dark forested areas. In urban environments, grassed areas are often mown regularly for human recreational and safety needs. This affects the availability of flowers for pollinators and also affects the persistence of these plant species. Mowing less often and outside peak flowering times can make a big difference for plants and pollinators. 
Similarly, large old trees are homes to myriad animals. Unless they pose a very real risk of danger to human lives, pruning overhanging branches can be better for the local ecosystem than removing the whole tree. 
Wildlife are rarely deterred by fences, so it is likely that most of the animals you see in your yard are also using your neighbours’ yards. Managing gardens as a collective landscape, rather than individual gardens, can keep wildlife happy while also enhancing neighbourhood communication.
Manu Saunders is post-doctoral research fellow (Ecology), Charles Sturt University and author for The Conversation. She can be contacted <a href="https://theconversation.com/profiles/manu-saunders-1448" target="_blank">here</a>.
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Birds, bees and bugs: your garden is an ecosystem, and it needs looking after

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<img src="https://counter.theconversation.edu.au/content/57114/count.gif" alt="The Conversation" width="1" height="1">
GUEST OBSERVER
Life in the city can be stressful – for birds just as much as people. For humans, cities are expressly designed to put roofs over heads and food within easy reach, but the opposite can be true for many urban birds. They can find food and shelter harder to come by in the concrete jungle – with some notable exceptions.
For any species in any habitat, survival is about problem-solving and adapting to the environment. So what street smarts do city birds need? And why do some species, such as lorikeets, crows and ravens, seem to dominate our urban landscapes?
In general, urban birds must be bolder than those that remain in natural habitats, as can be seen by the boldness (or “habituation”) with which some species will forage for food with people nearby. But they also need to be able to avoid or retreat from unfamiliar objects or situations if they seem dangerous.
City birds also need to withstand exposure to a wide range of pathogens. A study of birds in Barbados found that urban birds have enhanced immune systems relative to their country counterparts.
While we have changed the environment in which some birds live, reducing resources in terms of food and shelter and increasing the number of pathogens that may impact their health, some birds have largely benefited from the new way of life.
<h2>Winners and losers</h2>
Within the urban ecosystem, there are winners and losers in the bird world. The suburban landscape, for example, now provides more nectar from flowers than native vegetation due to the gardens that people have established. This is a big help to nectar-feeding parrots such as Rainbow Lorikeets.
A recent study in Sydney found that the lorikeets benefit from the increased abundance of flowers in urban areas, and their numbers were higher in the leafy suburbs than in bushland.
But if urban areas are such a rich source of nectar, why are some nectar-feeding species declining?
The Regent Honeyeater feeds mainly on nectar and other plant sugars. It has been seen in orchards and urban gardens, but is listed as critically endangered by the federal government.
This is partly because widespread clearance of woodland habitat has led to the increase of the aggressive Noisy Miner and Red Wattlebird. These species find it easy to “bully” other birds in open habitats. Noisy Miners have been observed pulling apart Regent Honeyeaters' nests as they were being built.
Regent Honeyeaters, in contrast, are less adaptable to changed landscapes, because they are migratory and rely on detailed knowledge of existing food sources. If these resources are changed or removed, they may not have enough interconnected patches of habitat to move safely towards new resources – potentially leaving them vulnerable to cats, foxes and aggression from other birds.
Habitat loss can threaten some bird species or even leave them at risk of dying out if they do not locate alternative resources. The ability to find new food sources therefore becomes a valuable survival skill.
<h2>What’s more useful: flexibility or intelligence?</h2>
For some bird species, flexibility in finding food is crucial in making a successful switch to urban environments. One example is the Grey-crowned Babbler, which is endangered in Victoria, but my colleagues and I have documented it living in a suburban area in Dubbo, New South Wales.
This species usually nests in coniferous woodland and forages in the leaf litter beneath the trees. But in Dubbo, we saw these birds feeding on lawns, in playgrounds and even in leaf litter along a train track at the back of urban housing, sometimes visiting backyards along the way. This suggests that these birds can survive the loss of their woodland habitat by being sufficiently adaptable to life in the suburbs – as long as they can continue to find enough food, disperse between nearby groups and have access to native nesting trees.
For other species, such as crows and ravens, intelligence seems to be the key. These species can survive anywhere in the urban sprawl, including places where trees are scarce but rubbish bins are everywhere. Crows and ravens can literally pull food out of a bin and eat it – clearly a learned behaviour that has resulted from problem-solving.
These birds are highly opportunistic and social, allowing them to learn new ways of adapting to the almost complete removal of their natural environment.
<h2>Survive and thrive</h2>
What we can deduce from these examples is that some birds, like Rainbow Lorikeets and Grey-crowned Babblers, can adapt successfully to the urban sprawl as long as some characteristics of their habitat still remain. Other species, such as crows, have gone a step further and worked out how to survive purely on urban resources – effectively making a living in an environment that is completely unnatural to them.
This suggests that the more we urbanise an area without natural aspects, the less bird diversity we will have – and the more our urban areas will come to be dominated by those few species that are hardy, clever or adaptable enough to thrive.
Luckily, some councils in Australia and cities throughout the world are bringing the natural aspects of the forest back into the concrete jungle, so that a wider range of birds might survive here. More research is needed to work out exactly what each species will need, but planting more native plants is always a good start.
Kathryn Teare Ada Lambert is associate lecturer, University of New England and author for The Conversation. She can be contacted <a href="https://theconversation.com/profiles/kathryn-teare-ada-lambert-186436" target="_blank">here</a>.
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