AVIARY DESIGN

“Birds are the most accomplished aeronauts the world has ever seen. They fly high and low, at great speed, and very slowly. And always with extraordinary precision and control.”

Sir David Attenborough
The Life of Birds (1998)

The following report features descriptions and images that were taken at, and describe, the Higher Ground Raptor Centre (HGRC) in the Southern Highlands of NSW, Australia over the years between 2012-2021. During this time the centre was created, constructed and continually improved by Peggy McDonald and Ross Robinson on what was then Peggy’s property and home.

For the first time, Australia had a dedicated raptor rehabilitation centre. This was home to more than 15 aviaries and other facilities, on par with the gold standard set by those seen by Peggy on her Churchill Fellowship journey to some of the best raptor rehabilitation spaces in the world.

ARCC Inc hopes this precedent will encourage the construction of similar aviary facilities around the country as greater understanding of these magnificent birds requirements prior to successful release is realised.

In mid-2021 and after the trauma of the bushfires, it was time for a new custodian. Peggy and Keith’s home and property were sold and the wonderful  Odonata Foundation took over the guardianship role of HGRC, and have protected and recognised its importance since. Without them the centre may well not have survived, and Nigel and Lisa will always have Peggy’s enduring gratitude.

The essential purpose of any aviary, no matter the size, is to provide appropriate space for the bird’s physical and mental condition.

As birds move through the facilities with the aviaries increasing in size, the ultimate aim is to provide an appropriate space at each stage of rehabilitation. Ultimately, this enables the bird to be released with a degree of fitness that allows it to both thrive and live normally back in its wild home territory.

These birds are the supreme athletes of the skies, the sky hunters, and along with that title comes the great responsibility on our part to make sure they are in excellent condition when we release them.

Feathers, body score, sight, hearing, wings, legs, feet and the ability to hunt, locomote, fly and breed normally when released are all critical factors that we must consider as part of our duty of care before we set a bird free again.

Here in NSW this is not only an ethical standpoint but also a legality set out in The Code: Code of Practice for Injured, Sick and Orphaned Birds of Prey | NSW Environment and Heritage

NSW, and some other states/territories, have minimum standard sizes for aviaries covering different stages of rehabilitation and species.

Factors such as cost, space, location and rehabilitator time constraints also need to be taken into consideration. It is appreciated that not everyone can have a 100m round aviary in their backyard, but we can all work within our budgets and limitations to build adequate and good holding facilities and pass on birds to more suitable amenities as their health improves.

This was always the initial focus of the HGRC, alongside providing a first class arrangement of facilities. The following descriptions briefly detail the major specialised structures, with images, of those at the Southern Highlands facility. The premises are also home to nine other smaller aviaries and an intensive care centre.

The author has been fortunate enough to complete five month-long internships at the Abu Dhabi Falcon Hospital (ADFH) between 2012 and 2018, as well as being awarded a Churchill Fellowship to study at some of the best raptor rehabilitation centres in the world, including the Carolina Raptor Center (North Carolina), The Raptor Center (University of Minnesota), Cobequid Wildlife Rehabilitation Centre (Nova Scotia), the Alaska Raptor Center (Sitka, Alaska), and the Moholoholo Animal Rehabilitation Centre (Hoedspruit, South Africa). The knowledge gained from these journeys has been invaluable in constructing a facility that meets world class standards.,

One of the many discoveries at the ADFH was their round free-flight aviaries. For decades it was debated that in Australia we were not giving our rehabilitated raptors the best chance to survive post-release due, in part, to the use of small rectangular aviaries. At the ADFH one round aviary was used as the first stage of reconditioning for hundreds of wild rehabilitated raptors (mostly falcons) released annually at migration time under the late HH Sheik Zayed’s falcon release programme.



One of the round aviaries at the Abu Dhabi Falcon Hospital, used for the pre-release conditioning of wild falcons. Gratitude to the ADFH for allowing this image to be used.

In order to ensure survival after release, we need to ensure that raptors in human care are fit and able to fly continuously, manoeuvre mid-air, hunt, take off, speed up and slow down their flight, brake and land.

Square or rectangular aviaries, while suitable for the early stages of rehabilitation, where the bird may not be particularly mobile, do not permit continuous flight or flight at speed, and therefore are not appropriate for preparing a raptor for release. Birds in these aviaries can only fly (if at all) from end to end, or one perch to another. For species that fly many hundreds of kilometres, or at speeds up to 70km/hr, this is insufficient.

A round aviary with a central pavilion removes the visual and physical barrier to flight, and allows and encourages birds to fly continuously in a circular fashion. The central pavilion may be used as a separate holding facility, but has the primary function of not enabling the birds, particularly the faster birds, to see an end point when flying. This encourages circular continuous flight rather than just back and forth, perch to perch.

Circular aviaries have been utilised for may years in the Middle East, both to maintain fitness in between seasons for highly prized hunting and racing falcons, as well as for raptors undergoing rehabilitation for release. Circular aviaries are also used in raptor rehabilitation in North America. The level of reconditioning and fitness achieved in this designs is far, far beyond what can be achieved in a square or rectangular aviary, regardless of size.

The first round free-flight aviary based on the ADFH design was completed in 2014 after a rigorous fundraising effort. The Peter Spitzer Flight Aviary (PSFA) at the HGRC was and remains the first of its type in the Southern Hemisphere.

Photographer: Peg McDonald

It was adapted to suit the temperate conditions of the Southern Highlands: rain, frost, cold, hail (below) and the odd snowfall, instead of the intense heat and ferocious sand storms of Abu Dhabi! 

Climate always needs to be taken into account when constructing aviaries. Whereas the aviaries at the ADFH have semi-solid walls and air-conditioning, the PSFA at HGRC has incorporated specialised netting that allows the passage of snow and rain through the roof to avoid build-up and overburden to the structure, and mesh and shadecloth for the walls that provides some visual barrier but permits critical airflow to maintain ventilation.

Photographer: Peg McDonald

The PSFA  is 100 m in circumference, 6m to 8m high and adjoins two traditional rectangular aviaries, 18 m x 5 m x 4 m in total (to the left of the picture). These can remain separate, be joined, or be opened to link and form one open complex with the birds having access to all areas.

Photographer: Peg McDonald

The roof is made with  UV-resistant salmon netting. The walls utilised bird netting with a stainless steel thread running through, and lined with shade cloth. The lower third of the aviary walls have an additional layer of industrial webbing to provide privacy for birds on the ground stumps or in the pool. There are three bays with solid walls built in, for weather protection and variation in three-dimensional space. 

Photographer: Mark Kelly

There is a personal access door for human use, as well as hinged vehicle access doors for machinery (only to be used when the aviary is unoccupied). The vehicle doors can be used for local soft releases as well.

Photographer: Peg McDonald

One of the essential design features of the round aviaries is the use of a central pavilion. The central pavilion of the aviary can be a separate holding facility, but its primary function is to prevent the birds, particularly fast birds, from seeing an end point when flying. This encourages continuous circular flight rather than just back and forth, from perch to perch, as seen in rectangular spaces.

Photographer: Peg McDonald

The aviary floor is raised about 30cm from the surroundings, and the substrate base is a minimum depth of twenty centimetres of blue metal (gravel) to encourage drainage. A layer of washed river sand covers the entire base to a depth of around 30-40cm. This is easily spot-cleaned and raked over, and is a more hostile environment to pathogens than organic substrates such as soil. Sand is changed when needed, according to climate and use.

The aviaries contain natural furnishings such as wooden perches of varying types and dimensions, changed regularly and generally covered in Astroturf, stump and posts, logs, bushes and free flowing pools in the two large round free flights. Small established trees provide roosting sites and different flight pathways. Remember that in large free-flight aviaries the birds can be flying at great speeds and should not be landing onto inflexible perches that are hard and smooth. Avoiding the development of pododermatitis (bumblefoot) must always be a foremost consideration.

Each aviary is covered by wide view CCTV (with thanks to Vetafarm) allowing remote monitoring of all birds, multiple sprinkler systems, water and electricity access.

Detailed specs, materials, construction methods and videos of the birds in flight can be accessed at Higher Ground Raptor Centre's website, Higher Ground Raptors | Round Aviary

Photographer: Peg McDonald

As with all outdoor raptor housing, other factors that must always be taken into consideration include the following:

• Ventilation and light
• Weather protection and shelter 
• Predator proofing
• Enrichment
• Water for bathing 
• Water for drinking
• Substrate
• Feeding hatches
• Ease of access for machinery when needed
• Monitoring 

Your state standards will also give information on these topics. If your state or territory does not have guidelines then we suggest following the excellent code published by the NSW Office of Environment and Heritage, with contributions by several experienced and knowledgeable raptor rehabilitators and veterinarians.

Code of Practice for Injured, Sick and Orphaned Birds of Prey | NSW Environment and Heritage

Photographer: Mark Kelly

This aviary primarily  functions as a space to safely hold birds and animals and allow for fast access and easy evacuation. However, as the idea became feasible it was obvious that it could be a lot more than just the original intention.

Further practical uses include:

•  A quarantine space
• A  holding facility for all types of creatures being looked after by carers in a fire,flood or natural disaster path to relieve them of that sense of being overwhelmed and allow them to concentrate on their personal and property well-being.
• A perfect orphan raising facility for birds unable to be reunited. A centre entrance  allows access to the middle of the facility, and from that space each individual aviary has a door and feeding shute enabling birds to be fed without seeing a human.
• Normal aviary holding space with a front opening door to allow individual access to the free flight area, as well as the centre access.

Photographer: Mark Kelly

Construction materials consisted basically of steel and netting as used in the Colley family aviary, with a washed river sand base.

The aviary was designed as a pie shaped space with separate bays that house birds safely and spaciously, each bay with individual access to a circular flight. The lower half of each individual space, the space walls and the roof are steel sheeting. Netting as used in the Colley Family aviary is attached above the sheeting to the roof.



A unique and complex roof system was constructed by builder Ross to allow for the addition of 16 single bays and a walkway to the central area..

Each individual bay can be accessed from behind utilising a walkway that begins as a personal access door on the perimeter. Each has a private feeding shute, enclosed space for hack box and feeding shelf, perching system, access to the elements  and individual exit with a large opening gate to the flight space.

ARCC Inc hopes this precedent will encourage the construction of similar aviary facilities around the country as greater understanding of these magnificent birds requirements prior to successful release is realised.

We are always happy to personally answer questions about the aviaries outlined in this report and their construction. Please contact us to find out more.

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Photographer: Mark Kelly