Identification
Physical Characteristics
Size: Females are relatively large and stout, with a body length of about 12-15mm. Males are tiny and rarely seen, measuring only 2-3mm.
Coloration: The colouration is key to its camouflage. The body is a mottled blend of white, grey, brown, and black, perfectly mimicking the texture and colour of a bird dropping. The cephalothorax and legs are typically a darker brown or reddish-brown and are held tightly against the body when at rest.
Key Features: The most distinguishing feature is the almost perfect mimicry of a bird dropping. The large, lumpy, white-and-black abdomen is unmistakable. The clusters of large, brown, ball-like egg sacs are another key identifier.
Biology & Lifecycle
Development & Reproduction
Reproduction Rate: A single female can lay over 2,500 eggs in her lifetime, distributed among her many egg sacs. This high reproductive output is crucial for sustaining the population, as mortality among spiderlings is very high.
Lifecycle Details
Egg Stage
The egg sacs are a highly conspicuous feature of this species. After mating, the female produces up to 13 large, spherical egg sacs, each containing over 200 eggs. These sacs are made of tough, brown silk and are connected by a network of threads, resembling a cluster of grapes. They are suspended from a branch, often near where the female rests. The tough outer casing protects the eggs from predators and weather throughout the winter.
Larval Stage
Upon hatching within the sac, the spiderlings remain inside, moulting once before emerging. This stage is technically a 'post-embryonic' stage.
Pupal Stage
Spiders do not undergo a pupal stage. Their development is direct, from spiderling to adult through successive moults.
Adult Stage
Females live for about a year. After reaching maturity in autumn, they mate and begin producing their egg sacs. They can often be found guarding these sacs until the first frosts. Males have a much shorter lifespan, their sole purpose being to locate and mate with a female.
Reproduction Rate
A single female can lay over 2,500 eggs in her lifetime, distributed among her many egg sacs. This high reproductive output is crucial for sustaining the population, as mortality among spiderlings is very high.
Generations Per Year
There is one generation per year.
Development Time
Spiderlings emerge from the egg sacs in spring. They disperse and grow throughout the summer, reaching sexual maturity by autumn. The entire lifecycle is closely tied to the seasons.
Seasonal Cycle
Adult females are most prominent in late summer and autumn when they are fully grown and creating their egg sacs. Spiderlings emerge in spring and are active through summer. The species overwinters as eggs.
Environmental Factors
The successful completion of their lifecycle depends on a healthy population of their specific moth prey, suitable plants for hunting and attaching egg sacs, and a climate with distinct seasons that cue their development and reproduction.
Habitat & Distribution
Preferred Habitats
- Open woodlands and forests.
- Suburban parks and gardens, where they find suitable foliage and prey.
- Orchards are a classic habitat, giving them the alternative name 'Orchard Spider'.
- They are typically found in shrubs and small trees, usually 1-2 meters off the ground.
- Plants with broad leaves or complex branching offer ideal sites for camouflage and hunting.
Distribution Patterns
Australian Distribution
Common in the eastern and southern states, including Queensland, New South Wales, Victoria, Tasmania, and parts of South Australia and Western Australia.
Climate Zones
- Subtropical
- Temperate
Urban vs Rural Distribution
Found in both rural and urban settings. It adapts well to suburban gardens and parklands that provide suitable vegetation and moth populations.
Native Range
Native to Australia.
Introduced Range
Not an introduced species.
Introduction History
This species is a native component of Australia's fauna.
Current Spread
The species' distribution is stable within its climatic range and is not considered to be expanding or invasive.
Limiting Factors
Its distribution is limited by climatic extremes (arid or alpine regions) and the absence of its specific moth prey. A lack of suitable shrubbery for shelter would also be a limiting factor.
Behavior & Diet
Activity Pattern
Strictly nocturnal. During the day, the female remains completely motionless, tucking her legs in and relying on her camouflage to avoid predators. At night, she emerges to hunt.
Dietary Preferences
Feeding Habits
A highly specialized carnivore with a very narrow dietary preference.
Health Risks
Always consult healthcare professionals for medical concerns related to pest exposure.
Disease Transmission
- There is no evidence or risk of this spider transmitting any diseases.
- It is not a carrier of any known human pathogens.
- It poses no risk of bacterial, viral, or parasitic transmission.
- This spider is not associated with any disease-related health concerns.
- It does not come into contact with materials that would lead to contamination.
Allergens and Respiratory Issues
Allergic reactions to spider venom are always theoretically possible but are undocumented and would be exceptionally rare for this species, which is not known to bite humans.
Contamination Risk
There is zero risk of food or surface contamination. It is an outdoor spider that does not enter homes or seek human food.
Vulnerable Populations
- There are no specific vulnerable populations. This spider poses no threat to children, the elderly, or pets.
- Curious children might touch it, but the spider's response is to remain still or drop away, not to bite.
- Gardeners are the most likely to encounter them but are not at any risk.
- Pets may be curious but are highly unlikely to be harmed.
- There are no concerns for immunocompromised or allergic individuals beyond the general caution applied to any wildlife.
Symptoms of Exposure
- There are no documented symptoms from a bite because they are not known to bite people.
- In the highly improbable event of a bite, it would likely be a minor mechanical puncture with no significant venom effects.
- No medical attention would be required.
- The primary human reaction is curiosity or being startled by its strange appearance.
- There are no known health risks to manage.
Transmission Methods
- Not applicable. There are no health risks to be transmitted.
- Direct contact poses no threat.
- It is not a disease vector.
- Food contamination is not a risk.
- Respiratory and surface contact are not pathways for any health issues.
Risk Severity
The overall health risk is rated as Extremely Low. They are considered completely harmless to humans.
Economic Impact
Treatment Costs
Professional Treatment
Professional treatment is not warranted or recommended. A call-out for simple relocation might cost $100-$200, but this is rarely necessary.
Prevention Costs
No prevention costs are required.
Diy Treatment
$0. The only 'DIY treatment' would be manually relocating the spider or its egg sacs, which requires no special equipment.
Property Damage
Structural Damage
This spider causes no damage to property, structures, or plants.
Garden Damage
It does not damage garden plants. In fact, it is beneficial.
Food Contamination
There is no risk of food contamination.
Equipment Damage
There is no risk of equipment damage.
Business Impact
Restaurant Issues
None. It is not found in environments that would impact food service.
Retail Impact
None.
Reputation Damage
None.
Operational Disruption
The only potential impact is on commercial orchards, where its presence is generally seen as neutral or beneficial. Some growers may be concerned about the egg sacs, but they pose no threat to the fruit or trees.
Agricultural Impact
Crop Damage
No crop damage.
Yield Loss
No yield loss.
Beneficial Aspects
It plays a positive role in agriculture, particularly in orchards. By preying specifically on male noctuid moths, it helps to reduce the breeding population of several pest species, such as cutworms and armyworms, which can damage crops. It is a natural form of biological pest control.
Economic Loss
There is no economic loss associated with this spider. Its impact is economically beneficial, albeit on a small scale.
Indirect Costs
Healthcare Costs
None.
Cleanup Costs
The only potential cost is the time taken for a gardener to prune off and dispose of the egg sac clusters if they are considered unsightly. This is a minor, optional task.
Replacement Costs
None.
Preventive Maintenance
None required.
Detection & Signs
Visual Signs
- The term 'infestation' is not appropriate, but signs of presence include seeing the camouflaged female on a leaf.
- The most obvious and common sign is finding the cluster of large, brown, spherical egg sacs hanging from a twig.
- The spider itself is often very difficult to spot due to its camouflage.
- There are no webs or other typical signs of spider presence.
- You will not see multiple adult spiders together.
Physical Evidence
- The main physical evidence is the bunch of egg sacs, which can remain long after the spider has died.
- Discarded moth wings may occasionally be found on the ground below the spider's hunting perch.
- There are no faecal spots, smears, or other traces.
- Finding a tiny (2-3mm) male spider on a plant is a very rare but definitive sign.
- There is no damage to plants or property.
Behavioral Signs
- Observing a spider hanging from a thread at night, motionless, is a sign it is hunting.
- The spider remaining completely still when disturbed during the day.
- It will not show aggression or run away quickly; its defence is to stay still.
- You might observe moths behaving erratically near the spider at night.
- This is a solitary, sedentary spider, so you won't see movement or activity during the day.
Seasonal Indicators
- The large, conspicuous egg sacs appear in late autumn and winter and persist for many months.
- Adult females are largest and most likely to be seen (if you look carefully) in late summer and autumn.
- Tiny spiderlings may be seen dispersing from the sacs in spring.
- It is a species whose signs (egg sacs) are more prominent in winter, even though the adult spider is gone.
Early Warning Signals
- Finding a single female spider in your garden is the first sign.
- The appearance of the egg sacs is a clear indicator that the spider has completed its lifecycle in your garden.
- A healthy population of nocturnal moths in your garden may attract these spiders.
- There are no 'early warnings' of a problem, as they do not cause problems.
Prevention
Sanitation Measures
- Sanitation measures are not applicable or effective for this outdoor, foliage-dwelling spider.
- General garden tidiness will not deter them.
- They are not attracted to waste, water sources, or clutter.
- Reducing outdoor lighting might reduce the moth population, but this could also negatively impact other wildlife.
- There are no specific sanitation protocols relevant to this species.
Exclusion Methods
- Exclusion is not necessary as this spider does not attempt to enter homes.
- They live exclusively outdoors in plants and pose no threat that would require exclusion.
- Standard home pest-proofing like screens and seals is irrelevant for this species.
- No structural modifications are needed.
- They are not a species of concern for indoor pest control.
Landscaping Tips
- There are no specific landscaping changes that will reliably deter this spider. They are adaptable to a wide range of common garden shrubs.
- Heavy pruning of shrubs could remove their habitat, but this is not necessary.
- If you wish to discourage them, maintaining a very open, simple garden with minimal dense shrubbery might make it less attractive.
- Conversely, to encourage these beneficial spiders, plant a variety of native shrubs that attract moths.
- As they are harmless and beneficial, the best landscaping tip is to simply leave them be and enjoy having a unique piece of Australian wildlife in your garden.
Monitoring Strategies
- Monitoring is not required for control purposes. It would be purely for interest.
- You can monitor their presence by searching the leaves of shrubs in your garden with a keen eye.
- Look for their distinctive egg sacs, which are the easiest sign to spot.
- Night-time observation with a torch can reveal their hunting behaviour.
- No traps or professional monitoring services are needed.
Environmental Modification
- No environmental modifications are necessary or recommended for control.
- The use of broad-spectrum insecticides in the garden to kill moths would be the only way to remove their food source, but this is highly discouraged as it will kill beneficial insects like pollinators and disrupt the ecosystem.
- Altering temperature or humidity is not feasible outdoors.
- The most responsible approach is to not modify the environment in an attempt to get rid of them.
Control Methods
Professional Treatment Methods
Chemical Control
Not applicable or recommended. Chemical control is entirely unnecessary for this harmless and beneficial species. No professional pest controller should agree to spray for a Bird-dropping Spider.
Biological Control
No biological control agents are needed. This spider is itself a biological control agent.
Physical Control
If the presence of the spider or its egg sacs in a particular spot is highly undesirable (e.g., right next to a frequently used handle), the branch they are on can be carefully pruned and moved to another part of the garden. This is the only 'treatment' that should be considered.
Integrated Approach
The only appropriate 'Integrated Pest Management' approach is to identify the spider, recognise it as harmless and beneficial, and leave it alone. If relocation of an individual is absolutely necessary, use manual removal.
DIY Treatment Options
Natural Remedies
There are no natural remedies or deterrents, nor are any needed.
Home Made Traps
Traps are not effective and not necessary.
Deterrent Methods
There are no known deterrents.
Mechanical Control
If you feel you must remove the egg sacs, you can simply snip the twig they are hanging from and place it in your green waste bin or move it to a less conspicuous part of the garden. The spider itself can be gently coaxed onto a twig and moved if necessary.
Treatment Effectiveness
Success Rate
Manual removal of the spider or its egg sacs is 100% effective at removing them from a specific spot.
Timeframe
Removal is instantaneous.
Follow Up Required
No follow-up is required. It is unlikely another spider will take up the exact same position.
Seasonal Considerations
The spider is present in late summer/autumn, while the egg sacs are most prominent in autumn/winter. Any removal can be done when they are discovered.
Application Techniques
- Egg Sac Removal: Use clean secateurs or scissors to snip the supporting thread or twig.
- Spider Relocation: Gently nudge the spider onto a leaf or twig and carry it to a new location.
- No special safety protocols are needed as the spider is harmless.
- These techniques should be seen as a last resort if their presence is causing genuine distress.
Professional Services
Professional Treatment Services
Chemical Control
Not applicable or recommended. Chemical control is entirely unnecessary for this harmless and beneficial species. No professional pest controller should agree to spray for a Bird-dropping Spider.
Biological Control
No biological control agents are needed. This spider is itself a biological control agent.
Physical Control
If the presence of the spider or its egg sacs in a particular spot is highly undesirable (e.g., right next to a frequently used handle), the branch they are on can be carefully pruned and moved to another part of the garden. This is the only 'treatment' that should be considered.
Integrated Approach
The only appropriate 'Integrated Pest Management' approach is to identify the spider, recognise it as harmless and beneficial, and leave it alone. If relocation of an individual is absolutely necessary, use manual removal.
Professional Treatment Costs
Professional treatment is not warranted or recommended. A call-out for simple relocation might cost $100-$200, but this is rarely necessary.
Treatment Success Rates
Manual removal of the spider or its egg sacs is 100% effective at removing them from a specific spot.
Treatment Timeframe
Removal is instantaneous.
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Browse All ProvidersSeasonal Patterns
Spring Activity
In spring, spiderlings emerge from the egg sacs and disperse via ballooning. They are tiny and rarely noticed as they begin to grow.
Summer Activity
Throughout summer, the spiders grow, moult, and develop their camouflage. They are actively hunting at night but remain well-hidden during the day.
Autumn Activity
This is the peak season for adult females. They are at their largest, and this is when they mate and produce their large, conspicuous clusters of egg sacs.
Winter Activity
The adult female will perish with the onset of cold weather. The species survives the winter as eggs, protected within the durable egg sacs, which remain hanging on the plant.
Breeding Season
Mating occurs in autumn.
Peak Activity Period
The term 'infestation' is not appropriate. They are most likely to be noticed in late autumn and winter when their large egg sac clusters are visible.
Environmental Factors
Temperature Effects
Warm temperatures are required for growth and hunting. Cold temperatures trigger the end of the adult's life cycle.
Humidity Effects
Moderate humidity is part of their preferred temperate habitat, but they have no extreme requirements.
Photoperiod Effects
Decreasing day length in autumn is a likely cue for triggering the final stages of maturation and reproduction.
Weather Patterns
They are resilient to rain, but strong winds could damage their hunting perch or egg sac suspension.
Legal Considerations
Pest Status
This spider has no official pest status. It is recognised as a native, beneficial species.
Control Regulations
There are no regulations governing its control. Standard regulations on pesticide use would apply if misused, but chemical control is not appropriate for this species.
Professional Requirements
No specific professional requirements exist, but any licensed pest controller should recognise the species as harmless and advise against treatment.
Environmental Considerations
The primary consideration is to avoid harming a native species that contributes to the local ecosystem by controlling pest moths. Using pesticides would be environmentally irresponsible.
Compliance Requirements
- There are no compliance requirements for homeowners.
- Pest controllers should adhere to industry codes of practice, which advocate for minimal environmental impact.
- No permits or reporting are needed.
- No specific state or territory regulations apply to this species.
- Responsible pest management principles dictate that it should be left alone.
Frequently Asked Questions
What makes the Bird-dropping Spider different from other garden spiders?
The Bird-dropping Spider is different in almost every way from common garden spiders like orb weavers or huntsmans. Its most striking difference is its method of avoiding predators and hunting prey. Instead of hiding or running, its body is shaped and coloured to perfectly mimic a bird dropping, a form of camouflage called mimesis. This makes it unattractive to its main predators, birds. Secondly, it does not build a web to catch food. It is a 'bolas spider' that employs aggressive chemical mimicry. At night, it releases a plume of scent that imitates the sex pheromones of female moths. This lures male moths directly to it, allowing the spider to snatch them from the air. This highly specialised hunting technique is unique and far different from the passive web-trapping of an orb weaver. Finally, its egg sacs are unique – large, hard, brown spheres hung in a grape-like cluster that persists through winter. Its appearance, hunting method, and reproductive structures make it a truly distinct and fascinating resident of Australian gardens.
Is the Bird-dropping Spider dangerous to humans or pets?
No, the Bird-dropping Spider is considered completely harmless to both humans and pets. It possesses a placid, non-aggressive temperament. Its primary defence mechanism is to remain perfectly still, relying on its camouflage to go unnoticed. If directly prodded or threatened, it is more likely to drop from its perch on a silk line than to bite. There are no credible records of this species biting a person. Its venom is specialised and potent enough to subdue its moth prey but is not considered medically significant for mammals. Children and pets are safe around it. The only 'risk' is being momentarily startled by its strange appearance if you are not expecting to see it. You can handle its presence in your garden with confidence, knowing it poses no threat to your family or animals.
What should I do if I find a Bird-dropping Spider in my garden?
If you find a Bird-dropping Spider, the best and most recommended course of action is to simply leave it alone and appreciate it. This spider is not a pest; it is a beneficial predator that helps to control populations of certain pest moths in your garden, like cutworms. It will not damage your plants and poses no health risk. It will not try to enter your home. If its location is truly problematic (for example, on a frequently used gate latch), you can easily relocate it. Gently coax the spider onto a twig or leaf and move it to a different shrub in a quieter part of your garden. If you find its cluster of brown, ball-like egg sacs and find them unsightly, you can prune the small branch they are attached to and move them as well, or dispose of them in your green waste. However, leaving them allows the next generation of these helpful spiders to emerge in spring. No chemical treatments are ever necessary or appropriate.
Why is this spider also called the 'Orchard Spider'?
The name 'Orchard Spider' is another common name for *Celaenia excavata* because it is frequently found in commercial and domestic fruit orchards. Orchards provide an ideal habitat for this spider. The structure of fruit trees, with their dense foliage and branching patterns, offers excellent daytime shelter, camouflage opportunities, and sturdy locations to hang their heavy egg sacs. More importantly, orchards are often home to significant populations of moths, including various species from the Noctuidae family, which are the spider's specific prey. Some of these moths are considered agricultural pests, so the spider's presence in an orchard is beneficial. Early naturalists and orchardists frequently observed the spider and its distinctive egg sacs on apple, pear, and citrus trees, leading to the adoption of this very appropriate common name.
I found a bunch of brown balls hanging from a tree. Are these from the Bird-dropping Spider?
It is very likely that what you have found are the egg sacs of the Bird-dropping Spider. This is often the most conspicuous and easily identifiable sign of its presence, even more so than the spider itself. The sacs are quite distinctive. They are roughly spherical, about 10-12mm in diameter, and are constructed from tough, papery, brown-coloured silk. A single female will produce a number of these sacs (anywhere from one to thirteen) and hang them together in a cluster from a single, strong silk stalk attached to a twig. The entire structure looks very much like a small bunch of brown grapes or nuts. These sacs are laid in autumn and are designed to protect the eggs over winter, so you will often find them long after the adult female spider has gone. No other common Australian spider produces egg sacs with this specific appearance and arrangement.
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