This page is aimed at educating people of all ages about Australian diurnal and nocturnal raptors. It provides them with the opportunity to learn about, and gain an enhanced appreciation of our native raptors and their environment. If you would like more information, or a vist to your school or community group, or attendance at an event, please contact us via e-mail or phone 9756-0669 to discuss your requirements.
For Students: if you've found this page, then your teacher probably has, too, so don't risk a fail mark: do the research and write your essay in your own words! Near the bottom of this page is a list of references we used. If you are doing a homework assignment on raptors, we would encourage you to see if you can find any of them in your local library and read them. You might even find it interesting!
Contents :
A raptor is a carnivorous bird with a hooked beak which kills its prey with powerful talons, or claws. In other words, a raptor is a bird of prey. You can tell a raptor from other birds by looking at it to see if it has a hooked beak and sharp curved talons.
Raptors all catch their food with their powerful feet. Their beak is not a powerful, crushing “biting” beak like that of a parrot, but is very sharp, for tearing meat.
Australian raptors are true carnivores, which means they can only eat other animals, they cannot eat seeds or plants.
Some birds, like emus, have very strong legs and feet, and very dangerous claws, but they are not raptors: they have straight bills and eat plants.
Other birds, like parrots, have powerful, hooked bills, but they are not raptors either: they have relatively small feet adapted for climbing and eat seeds and nuts.
Kookaburras and kingfishers eat fish and small birds and animals, but they are not raptors: they have straight bills and small feet. The same goes for ravens, magpies, shrikes and butcher birds.
Frogmouths are sometimes mistaken for owls, with their huge yellow eyes and large bills with a slight curve at the tip, but they are actually part of the nightjar family, and are not raptors, either: their feet are smaller than an owl’s and are not nearly as strong.
2. Types of Australian Raptors
Scientists divide raptors into two large groups called “Orders.” They are FALCONIFORMES, which is made up of the diurnal or daytime birds of prey and STRIGIFORMES, which is made up of the nocturnal or night-time birds of prey. These two Orders are then broken down into “families”:
Order FALCONIFORMES is divided into two families, Accipitridae, which are kites, hawks and eagles, and Falconidae, which are falcons.
Order STRIGIFORMES is made up of family Tytonidae, the “true,” “tyto,” or “masked” owl, and Strigidae, the “ninox” or “hawk” owls.
Raptors are grouped this way for a very good reason. The groupings tell us which kinds of raptors are most closely related to each other.
There are 34 kinds (24 Falconiformes, 9 Strigiformes) of raptor in Australia, and around 400 kinds in the world.
The kinds of raptors native to Australia include kites, hawks, eagles, sea eagles, buzzards, harriers, osprey, falcons, hawk-owls and masked owls.
The raptors within each group are more closely related to each other than they are to the raptors in other groups. For example, two raptors from the hawk group, an eagle and a goshawk, are closer relatives than the eagle and a falcon.
Some of the more common kinds of
raptors
in Perth are the Kestrel (falcon), the Brown Goshawk (hawk), the
Black-Shouldered
Kite (kite), Boobook Owl (hawk owl) and the Barn Owl (masked owl).
A wildlife carer is someone who helps native animals that get sick or have been hurt or orphaned. Our main goal is to give the animals a second chance by rehabilitating them and releasing them back to the wild.
Wildlife carers are all volunteers. All the money that is used to pay vet bills and feed the animals comes from the carers’ own pockets, and from donations.
Because it is so complicated to look after many different kinds of animal, many carers choose to specialise and only take care of some of the different kinds of animals. We only take care of raptors. There are other carers around who specialise in parrots, magpies, kangaroos, small marsupials and even snakes, because even snakes sometimes get sick or hurt and they deserve our help just as much as the prettier, cuter animals do. Please don’t ever try to handle a sick or hurt snake yourself, though. When snakes are sick or hurt, they can get cranky, and you should always call in an expert.
People who find a sick or injured raptor can call us. We then make sure that someone, either ourselves or another carer can take the bird and look after it properly.
Once a raptor is brought to us, or we pick it up, it usually needs to see a veterinarian. The vet can assess the bird, and treat injuries like broken bones and wounds.
Carers give medicines, change bandages and give food and water to the injured raptors until they are better. We then make sure that they are fit and strong before they are released again.
Many raptors that are found are so ill that we are unable to help them, and they must be put down (euthanased).
It is against the law to keep wild animals as pets. Although they can become used to people, they still have their wild instincts, and can be dangerous if not handled correctly. They also have special housing and feeding needs.
The birds we use when we conduct displays at events or on school and community group visits are unable to survive in the wild because of previous injuries and would not be able to hunt successfully or in some cases, they have been captive-bred and hand-raised for the purposes of education.
There are many ways that a raptor can get into trouble. Many problems are caused by people. Car strike, hitting power lines, getting shot, eating poison or poisoned pest animals (like rats), habitat destruction and people trying to keep them as pets. All of these things can kill a raptor, or injure it and make it sick.
Of course, there are natural things that hurt raptors. Lots of young raptors are not very good at catching food, so they are found starving. They also get sick just like we do.
If you ever find a hurt animal, or a baby without its parents, you should always call a wildlife carer. Never try to feed a wild animal anything, because you don’t know what it eats, and you could make it very sick by giving it the wrong food.
Be very careful, a wild animal will
be
frightened of you and try to protect itself, so it will bite or
scratch.
Wildlife carers know what to feed these animals, and how to handle them
without getting hurt.
All raptors have extraordinarily good eyesight. They can see objects in greater detail than people, and can spot movement (like a mouse in the grass) a lot farther away than we can. Birds of prey can see with approximately two and half times the resolving power, and in about eight times the detail that a human being can.
Like most predators, raptors have eyes that face forward, rather than to the side. This means that the picture in one eye overlaps the picture in the other. This gives the bird (and us) stereoscopic vision, which makes it much easier to judge distances in three dimensions. That way they can judge the distance to a prey animal and calculate their strike when hunting.
Many diurnal raptors can focus on their surroundings in two ways. They have frontal vision, like we do, with three dimensional (binocular) sight, and they can also look sideways out of either eye and have detailed two dimensional (monocular) vision.
The owls have less well developed colour vision than the day time raptors. This is because they have more rods than cones in their retinas, unlike human beings, who have more cones than rods. Cones are the cells in the back of our eyes that allow us to see vivid colours and account for our “day” vision, whereas rods are the cells that enable the eye to see in the dark, but don’t detect colour very well. Owls have a greater proportion of rods because they are nocturnal and have adapted to hunting at night. Their eyes are also more forward facing than the diurnal raptors, so they have more three dimensional / binocular vision, and less two dimensional / monocular vision.
Even though you can’t see a raptor’s ears, they do have a very good sense of hearing. They are a small opening under the cheek feathers. Owls have larger, more sensitive ears than other raptors.
Some owls can locate prey just by the noise it makes. They do this by having one outer ear slightly higher and more forward on the bird’s head. The sound reaches each of the owl’s eardrums a fraction of a second apart, so the owl can tell not only what direction a sound came from (the way a human can) but also how far away the sound originated. This helps them to hunt on dark, moonless nights.
Raptors may have a good sense of taste, although it is difficult for us to say whether it is much like our own. They certainly can be choosy about what they eat, but some of it, especially raw offal or carrion (the preferred food of the wedge-tailed eagle) would certainly be quite unpalatable to a human being.
It is difficult to say whether raptors have a sense of smell. Some other birds have a sense of smell, and raptors do have smell sensing cells in their ‘nose’. But the part of their brain that deals with processing smells is relatively small.
Because birds are covered by
feathers,
they do not feel things on their skin in quite the same way people
do.
Their feathers do transmit sensations of pressure and the skin itself
is
quite sensitive. The area of skin around the beak (called the
cere)
is sensitive to touch, and the tongue is good at feeling
textures.
Even though a raptor’s feet are pretty tough and scaly looking, they
are
sensitive to touch too. It is important to note that birds of
prey
do NOT enjoy being petted or stroked by human beings, even their carers
and handlers.
A feather is made up of two parts, the shaft and the vane. The vane of a feather is made up of rows of interlocking barbs that come off either side of the shaft.
Contour feathers are the ones on the bird’s body. They give the raptor a sleek, streamlined shape when it is flying, and keep the body dry when it is raining.
Under the contour feathers, there are down feathers. These help insulate the bird against heat or cold.
There are also some feathers that look like hairs. They form the bristles around the mouth, and the eye lashes.
Owls have special feathers that make up the facial disk called “filoplumes.” These long, thin feathers channel sound to the owl’s ears, almost like a “radar dish.”
The biggest feathers are the flight feathers. They are found on the wings and tail, and are what allows birds to fly.
Owls have a special design feature on their feathers: the leading edges have a soft fringe that absorbs sound and enables them to fly silently.
Birds can raise or lower areas of feathers on their bodies as part of body language and the colour of feathers is important for birds being able to recognise their own kind.
Birds take care of their feathers every day by preening them with their beak. This keeps them in the right place and also spreads oils on them from the preen gland above the bird’s tail.
The oils from the preen gland help
the
feathers stay shiny and resist ultra violet radiation from the sun.
They
may be important for making vitamins (vitamin D). This is why pet
birds can look scruffy, if their owners stroke them too much and rub
the
special oils out of the feathers.
Each kind of raptor has its own ways of catching prey. Some use a variety of different strategies, others stick to one plan.
All raptors have a strong hunting instinct, but to actually catch prey, a young raptor must practice to perfect its technique.
It is estimated that, roughly, between 50 and 80 per cent of raptors die in their first year, after leaving the nest. Many starve, or are injured while hunting. This is sad, but is a natural part of the cycle of life.
If a raptor survives its first year, and learns to hunt, it is likely that it will survive several more years and breed, barring illness, accident, or predation by other species (including human beings.)
One of the most noticeable things about raptors is that they use their feet to capture prey. This requires very good foot and eye coordination. It also requires good wing and body coordination, since the bird is maneuvering itself through the air while it is trying to catch prey that is also moving (and trying to get away).
Most small raptors eat insects some of the time. They catch these by grabbing them off of a plant, or by catching them mid-air in their feet. Insects are often eaten on the wing.
Some owls and goshawks will sit quietly and wait for something to move on the ground. When they hear or see movement, they launch themselves from their hiding place in a surprise attack. The owls use silent flight to surprise their prey, and the goshawks use speed.
Some kinds of falcon are experts at chasing other birds and catching them with their speed and maneuverability in mid-air. Other raptors hunt from a soar, and glide down to the ground when they see prey.
Raptors in the hawk and owl families will kill their prey by crushing it with their powerful feet and talons. Falcons may kill their prey by biting through the back of the neck as well.
When a raptor eats, the prey is stood
on
with one or both feet, and the bird uses its beak to pluck fur or
feathers
before starting to eat. The back and neck muscles are used to
pull
on the prey to tear pieces off with the beak. Some raptors,
especially
the owls, will not bother with tearing up smaller prey: they will
simply
make sure it is dead, then swallow it whole.
The bodies of raptors are very strong compared to some other birds, and have lots of muscles to power the wings and legs. But they are often much smaller than they look, because of the feathers on them.
The head has the eyes and ears and brain, so it is like the control center for the rest of the bird. Because birds need to be light so they can fly, the bones of the skull are not very thick. Also, the beak is made of lighter keratin, like in our finger nails.
The head is attached to the body with a very flexible neck. The raptor uses this to shift its gaze, instead of moving the eyeballs like we do. The neck is also used to reach the beak all over the rest of the body when the bird is preening its feathers.
Daytime raptors have a ‘crop’ at the base of their neck that is used to store food they have just eaten. This means they can eat quickly before another raptor or a scavenger comes and steals their food. Once the food has been digested in the raptor’s stomach, the inedible parts, like fur, insect carapaces and bones, are brought up again as a pellet.
The wings are mostly bone and tendons under the feathers. Most of the muscles that are used to flap them are on the bird’s body, attached to the ends of the tendons. Raptors are very good at precision flying. The tail is used to help steer, and to slow the raptor down when it is landing. One special feature that is well-developed in raptors is the “alula” which corresponds to the human thumb. When raised at slow speed, this special group of rigid feathers prevents the wing from losing lift, and enables the bird to fly slowly, with maximum manoeverability. “Slots” on the front of a jet’s wing are based on the principle of a bird’s alula.
The legs of a raptor are very important. They are very strong and take the impact of landings, or grabbing prey. All the muscles are in the upper leg, and are attached to tendons in the lower legs and feet.
The feet of raptors are amazingly strong. Some raptors use their feet to crush their prey to death. The needle sharp talons are also used.
All these parts are a little different in different kinds of raptors. For example, a kite has long, broad wings for soaring; but a falcon has short pointed wings for flying fast. These differences are called adaptations.
So each kind of raptor is adapted for the kind of life it lives. The kite can spend hours looking for food on the ground below, and the falcon can use its speed to chase and catch very fast prey.
Other adaptations include an owl’s
keen
hearing, the very curved talons of the Osprey for catching fish, and
the
colour of the goshawk’s feathers that make it hard to see.
A food chain is made up of living things that eat other living things. Like this: grass is eaten by a grasshopper; the grasshopper is eaten by a small bird; and the small bird is eaten by a raptor. Food chains show us how the sun’s energy is used by plants to grow, and is then used by all the other animals in the chain too.
An ecosystem is all the interlinked food chains in an area, plus their surroundings. Ecology is the study of ecosystems, and how different parts of them are related.
Every kind of animal has to have certain things to live. Raptors need prey, good hunting spots, shelter and a place to nest.
Different kinds of raptor need different kinds of prey, hunting spots, shelter and nesting places. This means that there is less competition between different raptors for these things. For example, a Kestrel can live close to an Eagle, and the two will not compete for food because they eat different things. The Kestrel eats insects and the Eagle eats rabbits.
Raptors respond differently to changes in numbers of their prey. Some, like the Black Shouldered Kite will breed very quickly, while there is extra food for the young. Others can not breed fast enough to take advantage of short term increases in prey.
Raptors are an important part of
their
ecosystems. As predators, they can affect the way prey species
adapt.
They can also affect how many prey animals survive to breed, and thus
may
affect population growth rates.
As Human populations grow, we are using more and more resources to survive. We use more land for houses and agriculture, and make more waste.
Raptors can suffer either from habitat loss or change, or from things that we humans have put into the environment.
Habitat loss happens when natural vegetation is cleared, or some resource that the raptors need is taken away. For example, the removal of very old trees, which had nesting hollows for owls, or feral animals causing an important prey species to become extinct.
Things that people put into the environment can be dangerous chemicals, like pesticide and rat poison, or they can be physical things like cars, power lines and rubbish.
You can help raptors and other animals in some ways. Remember that using rat poisons or very strong pesticides can kill raptors. Raptors and other animals eat the animals that have been poisoned.
Plant native, local plants to attract native prey animals (insects as well as birds) and provide shelter. Leave old trees that may have nesting places.
Encourage your local government to keep natural bushland, and help restore what it already has.
Promote people’s respect for raptors by telling them that these birds are not ‘heartless killers’, but a beautiful and important part of nature. (Hands up who eats cows and chickens or even cheese?)
Only a few years ago, the government and most people thought of many large raptors as dangerous to livestock, or as pests. An increase in our understanding of these birds has changed the way many people look at them; and raptors are now protected by law. Unfortunately, despite this law, many raptors are still shot every year.
Wedge-tailed eagles were shot by the thousands before scientific research showed that they did not have an impact on the sheep farming industry. Rather, they may help reduce grazing competition with rabbits, as well as cleaning up carcasses and flies.
Scientists are learning more and more
about
raptors and their needs. This will benefit other animals
and
plants as well as the raptors. This is because, in order to
protect
a raptor species, its habitat and ecosystem must be conserved too.
10. Social Interaction and Behaviour
Raptors have many instinctive behaviour patterns. These are used in communication and courtship, as well as in hunting.
Although much of a raptor’s behaviour is based on instinct, they are intelligent and can modify behaviour by learning.
Hunting is an instinctive behaviour that is modified by learning. This learning happens when the young bird tries to hunt and finds it is rewarded with a meal when it does this a certain way.
Imprinting happens when a chick is very young. The image of its parents and siblings will carry through into adulthood, when the bird will select a mate and defend its territory against those who fit the image- its own species.
Young birds have instinctive patterns of behaviour with their siblings, but this can be changed through learning. For example, an older chick may learn that it gets more food by being bossy with its siblings, and will be a ‘dominant’ bird. A younger or smaller sibling may learn that it gets less aggression from the bigger chick by being patient and submissive.
Dominant and submissive behaviour may be important in later life when the smaller male must bring food to the female and let her have it. This allows the female to get on with brooding eggs or chicks. Pair bonding is also helped by courtship rituals between the pair.
Among some raptors, the dominant chick is usually the one most likely to survive, because it hogs all the food and may attack a weak sibling. This is sad, but it means that when food is scarce for the chicks, one will survive, instead of having two starve. In good times, more of the young will survive to fledge.
Raptors communicate using body language, as well as their voice. These postures and movements are instinctive. Every species of raptor has its own variation of this ‘language’.
Raptors can communicate how they are
feeling
by the way they hold their feathers. A nervous bird will flatten
all its feathers down close to its body to look small, but an
aggressive
bird will often puff up its feathers to look scary.
References
Fox, Nick (1994) Understanding the Bird of Prey Hancock House, Blaine (USA).
Hollands, David (1991) Birds of the Night Reed, Sydney.
Krebs, Charles J. (1985) Ecology HarperCollins, New York.
McFarland, David (1993) Animal Behaviour pp. 224, 254, 269. Longman Scientific and Technical, Singapore.
Olsen, J., Crone, F. and Olsen, P. (1993) Birds of Prey and Ground Birds of Australia Angus and Robertson, Sydney.
Olsen, Penny (1995) Australian Birds of Prey UNSW Press, Sydney.
Reader’s Digest Services Pty Ltd (1990) The Reader’s Digest Complete Book of Australian Birds Reader’s Digest (Australia), Sydney
Parry-Jones, Jemima (1998) Understanding Owls, David & Charles, Newton Abbot (UK)
Trounson, Donald and Molly (1987) Australia Land of Birds
pp.6,
16. Collins, Sydney.
Contributing Consultant Wildlife Carers
Apgar, Marra - Perth Raptor Care, Perth.
Pain, Philip - Eagles Heritage Raptor Wildlife Centre, Margaret River.
Society for the Preservation of Raptors, Margaret River