Buteo, buteo
The Common Buzzard
by Darren Burgess
Contents
pages 4-15 -
a collection of images of Buzzard behaviour
pages 18-21 -
how the
pages 22-25 -
on the
Buzzard flies
look out
pages 26-27 calls and hearing 2
pages 28-29 - Talons and Bill pages 30-31 - pull out poster of Buzzard
pages 32-33 - Males and Females who’s who?
pages 34-35 buzzard
ing and Eating
Catching Kill-
pages 36-39 tered and Harrased
pages 40-41 -
tory
Mobbed, Pes-
pages 46-47 -
Future gen-
pages 48-53 -
Past, present
pages 54-57 -
Falconry and
erations
Buzzard terri-
and future
pages 42-43 breeding season
Mating and the
pages 44-45 - Building nests
Buzzards
Introduction Over the last three months I have been studying the Common Buzzard (Buteo buteo) at two locations, Swanpool and Pendennis both in Falmouth Cornwall. Both sites have good tree cover allowing the Buzzard to nest, roost and take cover as well as open grassland to hunt and perform aerial displays. At each location is a territorial pair, which allowed me to compare and contrast between the two to give a more varied and precise study of the raptor. Over the three months I have witnessed and accounted the day-to-day lives and recorded them alongside research in this magazine with the aims to educate and inform about this bird of prey in this comprehensive study. Photographs taken of the Buzzards at these locations helped with recording the behaviour and accompany the research and observations.
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B ehaviour
B ehaviour
B ehaviour
B ehaviour
B ehaviour
B ehaviour
A study of the behaviour and daily life of the common buzzard
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...
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How the Buzzard Flies... The biggest question that comes to mind when thinking about birds is how do they fly? What lifts these animals off the ground? And why can’t we fly? There are many factors to consider when asking these questions. The most obvious answer is because of their wings and of course this is true but not the only reason. The Buzzards wings are shaped in a manner that causes the air to move more rapidly because it is travelling a greater distance so therefore it is thinning over its upper surfaces whereas the flow of air is slower and more direct than beneath its lower ones. The physics behind this dictates that the higher the velocity or speed is passing over a surface, the lower the pressure is on that surface. The theory first thought up by physicist Daniel Bernoulli explains upper air thinning out as it races to cover a greater distance in the same time as the air going under the wing. The lower pressure acts as a suction resulting in pulling the Buzzards wing upward ending up with lift that counter acts the pull of gravity. A great and simple way of testing this theory is to tear a strip of paper, hold it lengthways and blow along the top and you will see it magically rise against gravity. The angle that the buzzard positions its wing is called angle of at-
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tack and this deters whether the flight of the buzzard slows down or speeds up, and can dictate taking off and landing just like in an aeroplane. The forward motion though involved in gliding is from a slight decent using the wings and gravity to propel itself forward, it can also use flapping flight when winds are not strong enough to go forward or fly, also flapping is very important in take off flight as the initial momentum. If you have ever seen the common Buzzard in the skies of Great Britain you will have most likely seen it soaring elegantly as most raptors will do. Buzzards will sustain their flight for long periods of time without flapping their wings. But how can they do this with such little effort? It is because they take advantage of
updrafts when winds blow over hilly terrain or mostly from thermals which is from rising warm columns of air which hold the Buzzard in the sky as if on a plinth. The soaring Buzzard will spread its primary feathers which are the longer larger feathers you can see at the tip so that each acts as the equivalent to a small high aspect ratio wing which means turbulence is reduced at the tips giving that smooth gliding you see in its flight pattern although its wing is predominantly a low aspect ratio wing with well developed slots. A lot can be learnt about the buzzards flight just by looking at the shape of its wing as well as it can with all birds. The shape dictates its flight patterns, where it lives, if it hunts or is hunted, and quite importantly its speed of flight and how high it can fly. Birds speed of flight is not necessarily dictated by the size of the bird but mostly due to its shape and its lifestyle such as the ability to accelerate and decelerate allows them to avoid a predator or in the Buzzards case elude from the mobbing from other birds such as crows, gulls and kestrels or race back to defend its territory from other Buzzards with intent of over turning their throne. The Buzzard does fly at high altitudes and can do this because of its great eyesight and the ability to ride thermals.
The Buzzard which is of course a bird, is defined alongside all birds by its feathers which without they would be walking around amongst us. The common saying ‘light as a feather’ is used frequently and this of course refers to the almost weightlessness of them. Evolution has moulded feathers to perfection in their role and purpose. The structure of the feather starts at the quill which is held in the follicle in the skin of the bird just like a hair is to our head. Each side of the feather upwards, called the rachis, is the support for an intricate layout of vein type structures with the small barbules coming off of the vane and zipped together with small hooks thus making the Buzzard streamlined and resistant to fast moving airstreams. The Buzzard also has a very different type of feather, the down feather which possesses a much softer structure because its barbules do not contain hooklets like the outer contour feathers and is important in regulating warmth and insulation of the bird. The feathers are controlled by muscles that are attached to the walls of their sockets which are important for controlling its flight as well as other functions. The colours of the feathers on a buzzard are not colourful as are with other birds but instead more for camouflage purposes. The importance of feathers means maintenance is top priority and the Buzzard goes about this in two ways. The first is by preening a very common behaviour witnessed by all birds involving the careful cleaning, rearrangement and oiling of the feathers using the Buzzards bill. Oiling the feathers keeps them flexible and waterproof. The other way the Buzzard will maintain its feathers is by moulting. They must moult because like fingernails they
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... how the
Buzzard Flies
are lifeless once formed and any damage cannot be repaired so therefore have to be replaced. The growth of new feathers happen in the Buzzard usually twice over the period of a year and because the Buzzard stays here over winter and does not migrate to warmer climates it needs a warmer coat in the colder months. As previously mentioned wings and feathers aren’t the only anatomical features that have evolved in the evolution of birds. The skeletal structure has lost inadequate bones and gained vital ones as well as an effect called pneumatization which is the hollowing of the bones making them much lighter for flight, although these bones have lightened there are others such as the sternums which have strengthened for structural reasons and to support the wings. The respiratory system has also evolved to be proportionally larger than ours to suit the Buzzard in higher altitudes allowing higher extraction of oxygen than humans at about 20% more than mammals and for harder work outs as flying is much more demanding than walking. With feathers making between 6-9% and the skeleton 5% the respiratory counts as 1/5th of its body weight showing how important it is.
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The muscles of a large raptor such as the Buzzard are very strong as they have to kill and carry fairly large and heavy prey alongside their own body weight. A buzzard would be rendered useless though without the use of a good brain and birds have proportionally large brains compared to their closest relatives, lizards, and can more closely be resembled to rodents in brain size. Flight is a very demanding activity as there are many obstacles and dangers to avoid so a fast thinking brain with the aid of sharp eyes allows the buzzard to manoeuvre gracefully through the air.
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On the Look Out... The most impressive and most important sense for the Buzzard is its sight. It is so important because it allows for safe flight and spotting danger and of course most vitally spotting prey. The Buzzards eyes are placed at the front of the head with a prominent eye ridge giving it that distinctive raptor stare that is the quintessential portrayal of good eyesight. The saying is ‘eyes like a hawk’ but this goes alongside raptors such as the Buzzard just as significantly. They have binocular vision because of the placement in their head and is assisted by a double fovea for extra sharpness allowing Buzzards to spot their prey from over a mile away and enabling to accurately judge distances with vision between 6-8 times better than in humans. Raptors have large eyes in proportion to body mass at about 1.4x larger than other birds of the same weight. Due to the size of the eyeball in the socket it is limited in movement so uses its
head to look around as can be witnessed when flying as it moves its head from left to right in a robotic fashion. The layout of the eye, binocular vision and optimisation of giving maximum spatial awareness rather than light gathering means that the Buzzard is diurnal and limited to hunting in the day as the eye does not work well in low light so roosts when light is poor. Buzzards have a high density of receptors and other adaptations that maximise visual acuity. Humans have 200,000 receptors per millimetre squared where Buzzards have 1,000,000 per millimetre squared so this large difference allows it to see a higher range of colours than us making for stronger vision and the ability to distinguish objects at a distance more distinctly. The eye has two types of light capturing cells, the rod cells and the cone cells. The 23
cone cells work best in bright light and are responsible for colour and the rod cells work best in low light and are responsible for night vision. The Buzzards eye is 80% cone and 20% rods proving that the Buzzards eye works best in good light conditions and with these more intense light conditions the more photons are observed by the visual pigments, the more excitation of each cone and the brighter the light appears which is why you will see Buzzards hunting nearly all the time in good light. The eye is not spherical like ours and this flatter shape enables more of its visual field to be in focus as well as the lens being pushed further forward increasing the size of the image on the retina. A good example to explain the Buzzard eye is the way a telephoto lens works on a camera, the lens is further forward such as in a 300mm lens creating a larger image on the sensor or film but because the light has further to travel it needs more light to get a correctly exposed image. Raptors such as the Buzzard lack coloured eye drops in their cones so theories suggest that they have similar colour perception to us. Due to the colours of the plumage in Buzzards suggest that colour is relatively unimportant especially as there is no colour displays in courtship. When we switch on a light bulb we see it as a constant light as we cannot see at over 60hertz but the Buzzard alongside many other birds can see at a much wider hertz rate than us so they would see the bulb as a flickering light. This greater Hertz rate means that when in pursuit of prey or avoiding mobbing they will see the movements much slower which to us would look like a blur allowing for better agility and accuracy. When we look up at the stars we see the stars as a still image but incredibly birds can also see at a much slower Hertz rate so see the movement of the stars or sun as a constant movement. This higher range allows the buzzard to maintain a steady image vital in flight and pursuing prey. Since the eye is so important to the buzzard it is only right that it has the ability to protect it. It has eyelids but evolution has added a second line of defence present in most birds by developing what is called a nictitating membrane that is a concealed eyelid that moves horizontally across the eye like a windscreen wiper. The membrane is transparent so can still be seen through so the Buzzard can use it for example to clean debris or particles that have fallen in the eye during flight. 24
...on the Look Out
Buzzard Calls and Hearing...
The Buzzard has to compete with the sounds of all the other birds as well as other noise around so it is vital that it has its own unique call to identify from each other and not to be confused with other birds. There is a differentiation between a song and a call of a bird and Buzzards are not known to be birds of song but do possess a call and are very vocal for birds of prey. Calls normally serve a specific purpose such as alarm calls to signify if there is danger nearby to the partner in a mating pair or a call to ward off other Buzzards trespassing on its territory. They also use a call as a distraction technique if there is danger near the nest. Calls are also good for loca26
tion so when one Buzzard in a pair need to find each other. I have witnessed the female bird calling for the male when she is incubating the eggs for him to bring her food. Although the Buzzard will call from trees it mostly calls whilst in flight. The ability to know if it is your partner calling rather than another Buzzard is important too so birds can differentiate the calls of one bird from the other just like we can with one another. The call is very distinct and easily identifiable. It is a loud mewing (piiiiyay) falling in pitch at the end. It has been likened to a cats meow although I don’t see it myself.
When trying to follow the Buzzard call I came across a Jay mimicking the Buzzard skilfully. There are many theories as to why the Jay and other birds mimic the calls of others. The main theory is that a large repertoire of calls in some birds such as the Jay who belongs to the
crow family is important in selecting a mate. The larger expanse in vocal calls or mimicry has been shown to not only be for attracting a mate and stimulating females but to intimidate rivals. Although the Jay is a good impressionist it does not fool the original and the Buzzard does not respond to it. 27
Talons
Feet and Mouth are of course important to every living thing that has the fortuity of owning them and no different is it to the Buzzard. Without the possession of the typical forelimbs due to the replacement of wings it has to then rely much heavier on its bill and talons. The Buzzard comes under the order Accipitriformes which overall have the same design with the bill and feet. Typical accipitriformes have a sharp hooked bill and strong legs and feet with raptorial claws and an opposable hind claw all 28
together consisting of four toes which are widely separated. Avian feet like bills can determine a lot about the bird and relate to its lifestyle such as the buzzards sharp claws with well padded undersides to clasp prey. The bill which is hook like is predominantly used for tearing through flesh but is not all it is served to do. It also is used for preening, plucking, collecting material and constructing for nest building, egg turning, defending, and even in the hatching process.
and Bill...
Males and Females Who’s Who?
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Determining male from female in birds is chiefly followed by the rule that the male is the biggest of the pair but in Buzzards and all raptors this is the opposite. Sexual dimorphism refers to differences between the two sex groups such as morphology, ornamentation (although not very relevant to Buzzards) and also behaviour. The male Buzzard is somewhat smaller than the female and considerably enough to compare but why is this the case? Again many theories surround the reasoning. One theory suggests that it is so that the larger females can protect themselves from aggressive males and be dominant for proper pair bonding to occur so the male keeps to his main role as food bearer for both female and chicks.
Another main theory is that they are suited to catch different prey with the male being more agile due to its size so catches smaller prey and the female stronger to catch large prey to minimise competition with each other. Although Buzzards size and prey does not vary enough for this to be a fully justifiable theory it should not to be dismissed as when both are actively hunting when the chicks are older they may partition the prey sources within their territory. Other theories include that the female needs more energy reserves to produce her eggs or that while not hunting while incubating it needs more fasting endurance although the male does the hunting for her at this period. All these theories are more relevant in raptors that rely on speed to catch their prey rather than strength such as the buzzard but still have bearing. 33
Catching and The Buzzard is a ruthless and formidable killer and needs to be to sustain its raptor lifestyle. It commonly eats rabbits and other small mammals such as voles and mice but its diet is very varied and will eat reptiles, amphibians, birds as well as game birds and will even be seen in fields or following behind combine harvesters to feast on earthworms; an unusual behaviour for a bird of prey. Carrion can also be a very important part of their diet and help sustain them during the winter
months. Raptors have a varied way of capturing their prey and the Buzzard does this in two ways. The first is by soaring and spotting their prey on the ground with acute eyesight. When the buzzard spots the prey it will tuck its wings in to descend rapidly and then swoop in to grab it with its talons resulting in a life taking grasp of its victim. The other way is similar in capturing its prey but will spot its prey
Killing Eating... from a The Buzzard can be seen perched in a tree or commonly a telegraph pole as they are nicknamed ‘telegraph pole eagle’ and will look around for its prey with its telescopic eyes before gliding in to pursue it. The killing of its prey will be done with the razor sharp claws at the end of its powerful talons to give a coup de grace or deathblow. The Buzzards diet varies by season, and due to the higher abundance in active
prey it is no wonder why the breeding season is timed to be in spring running into summer as numbers of its prey are far more active. The male during this time has to support the female and chicks for periods during so it is vital that food is plentiful whereas it may not be when temperatures are lower. It is a common occurrence in most animals that they become opportunistic and switch food sources that are in abundance.
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Mobbing, Pestered and Harrased...
Spending 100’s of hours observing Buzzards and many of those hours going without even a glimpse the thing that helped me spot them and give away their location was an unusual one. After weeks of looking out for them I learnt that many of the times I spotted the Buzzard was due to them being mobbed by gulls and crows so I knew to hear out for the erratic squawking and calling. Fortunately for me in spotting but un36
fortunate for the Buzzards the gulls and crows regularly mobbed the Buzzard whenever it would fly in open spaces or in view. They fly around the buzzard making loud squawks and dive towards to peck and knock the Buzzard. The Buzzard twists on its back when closely approached pointing its talons towards the attacker in protection. I have even witnessed in extreme cases a Buzzard being cornered into a tree by 4 crows which mobbed and harassed the Buzzard for several minutes as the Buzzard
called out in distress. The mobbing I witnessed seemed to be a daily occurrence for the Buzzard and must be cause of a lot of stress for the bird but why does it not retaliate as it is a powerful bird and could cause its attackers harm. My theory suggests that it is simply to avoid from injury, if the Buzzard decided to come in conflict with these other birds there is a chance that wings could be broken or other injuries sustained
and once this happens then the Buzzard will not be able to hunt, therefore feed or sustain a family and ultimately resulting in death. Other theories suggest that as well as other raptors it is just not in its genetic makeup to retaliate as the Buzzards main form of attack is surprise and cant use this against the gulls and crows as they follow harass and make loud squawks to give no element of surprise and giving away location for the Buzzard. 37
Mobbing occurs for a variety of reasons, one is to try and move the bird of prey away from a nesting site and another as previously mentioned to take away the birds element of surprise so it cannot prey successfully on its target but in the case of the Buzzard and the gulls and crows this does not seem to be the reason for the Buzzard does not prey on either. Mobbing has been found to be a taught trait of birds. The buzzard becomes very conspicuous when being mobbed but surely the 38
gulls and crows would not do this to protect other birds or animals that fall prey to it? The behaviour of helping another from danger is known as altruism where another bird puts itself in danger to help another. The behaviour that appears initially as selflessness can be actually selfishness as the bird will do it to protect itself for it may be safer to keep the enemy closer in sight rather than not knowing where it is. Altruism does come into practice though when the
...mobbing, pestered and harrased
bird puts itself in danger to protect its young. But this still doesn’t explain the mobbing witnessed towards Buzzards by crows and gulls. There is possibility that the Buzzard prey on the young of crows and especially gulls as they appear clumsy at early age and also feed off the carrion of dead crows and gulls but I have not witnessed this. An additional theory could suggest that these birds witness the Buzzard killing and
eating prey so it is as simple as just an added protection or a just in case approach to a predator. This theory would apply because the Buzzard itself has been witnessed to mob larger birds of prey such as the golden eagle although the Buzzard is not its prey but does it as an added measure in case of predation.
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Buzzard Territory... Buzzards have overtaken the Kestrel as Britain’s most common bird of prey and that is testimony to its success. It now can be spotted in every county in Britain and breeds and nests in the majority of them. This abundance of Buzzards means that the battle for territory is very important and the demand for a good location is hard to find. Habitat selection in Buzzards is dictated by two important factors. The first is open land, which can support plenty of animals that the Buzzard can prey on as well as suitable posts. The second is a decent sized forested area to provide refuge for the Buzzard and for nesting. Once territories are established the Buzzard will fight to keep it, as it is important in attracting a mate especially if the Buzzards territory is a Lek, which is a traditional breeding site.
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The main aims of all territorial birds is to monopolise food resources and nesting sites. Territoriality also is important for the Buzzard in winter months for the control of limited food stock so defending a territory becomes a daily job. Contact between two males is a last resort; instead the Buzzard has developed warning calls to ward unwelcome visitors. If this does not it may perform visual aerial displays, chases and if all else fails combat. The return of a mating pair to the same location each year is called site tenacity and this is common in Buzzards who can retain their territories each year. The benefit of doing so is because the Buzzard is familiar with the area so knows the best spots for hunting, nesting and what dangers to avoid.
Mating and the Breeding Season... The arrival of springtime and the longer days sparks off hormones in the Buzzards brain which results in sex being on the mind and a few weeks later the advent of the mating season. The mating season is timed in Buzzards to maximise success of raising young with the higher abundance of food and the longer hunting hours to sustain the burden of egg laying and incubating in females or the increased energy used in aerial displays in males as well as the combined efforts of nest building. The male begins its courtship displays which is a truly magnificent sight by flying high in the sky to then fold its wings inwards and tumble down to the ground where he then regains composure and repeats this process again and again. Another even more impressive display is witnessed between two males who fly together and briefly make contact with each other by locking their talons together and flinging each other in the air with the female on looking nearby. Males will use the aerial battle as a part of their courtship display and is known as courtship fighting. Displays are classified by a function whether it is aggression, greeting or courtship but all relate back and are principally driven by the desire to mate. The reasons for these elaborate displays are ultimately for sexual selection. As many are aware the term was 42
coined by Charles Darwin and expresses the choice in mates, such as in the Buzzards case, the competing by means of aerial agility and strength for the opportunity to mate. It’s a game of winning; the winner takes it all and the loser standing small. The winning traits then will theoretically be inherited by the next generation giving the offspring the best possible start. Evolution is progressive not regressive so it is only wise that the males that hold the best territories will have the more chance of finding a mate and Buzzards will fight for their territories showing displays of aggression or in more extreme conditions result in combat. Buzzards are monogamous and mate for life. They stay together during the breeding seasons and come together again each year depending on both surviving and the male will still perform for her still. The cooperation of the pair results in increased functionality which in turn gives the young a better chance of survival. The male investment in a partnership is vital as he feeds the female a few weeks before and during the egg laying, incubation and some of the brooding period as she would not be able to do both otherwise.
Building Nests... The occurrence of nest building and the timing is also triggered in hormones in both male and female in accordance with the solar trigger, which happens in springtime. The nest building with Buzzards occurs early in the courtship relationship and will continue collecting throughout incubation and further so as a maintenance procedure. The complexity of the nest is one of nature’s great events as it is such a complex and functional structure and feat of engineering. The dexterity in building a nest is instinctive but complexity and structural materials of nests increase and improve year by year as skills and techniques grow. Perfection requires practice and instinct can be mastered. Materials used in nest building vary tremendously and can use anything from stones to grass and even in some cases man made materials. In the Buzzards cases the main structure of the nest is made from twigs that are interwoven to create a solid wire frame for the rest of the nest. The inlay is made of softer materials such as grasses and other vegetation as well as feathers and mosses. The softer materials are for cushioning, insulation, waterproofing and concealment of the eggs and also the decay of plants have been known to produce its own heat and this material is topped up 44
regularly during incubation. Nests provide protection from the nesting Buzzard as well as other animals predating on eggs of young chicks so location is a very important decision to make when choosing a nest site. The Buzzard usually nests in tall trees on the edge of forested areas where there is open grassland for the Buzzard to hunt. The trees are usually pines as they grow taller and have cover for longer as they do not shed their vegetation. They are built on a fork in a trees thick branch, which acts as the main foundation of the nest. The Buzzards nest location is changed year by year within the same territory especially if breeding isn’t successful. They will go back to an old nest every other year but will change to avoid other birds that mob them that may have discovered the location of the nest. The other for nest rotation is purely for sanitation purposes, although the nest may not deteriorate over the winter period it is prone to parasites and pathogens, which can result in being deadly for the Buzzard. The nest can be full of invertebrates and other pests that feed on the birds or their waste products so cleaning and providing new materials, some with pesticidal properties, to the nest regularly is vital. They Buzzard will also tidy by removing waste when possible as well as disposing of faecal sac and egg material.
Future Generations... The Buzzard has a clutch of between 2-4 eggs at three-day intervals in the middle of April. This is a conservative clutch size that will be more manageable by the Buzzard pair than if laying a large clutch. In the evolutionary stance of the Buzzard it has showed that reproduction is maximised over the lifetime of the female by laying fewer than it would be laying a higher quantity per brood. The female does all of the incubation in the pair and the male will provide her with all the food she needs during this period. Each succeeding egg takes 33-35 days to hatch at 2 day intervals. The incubation time is connected largely to the size and weight of the egg so this suggests that the Buzzards egg is a fairly medium sized egg. The female will sit on the eggs regulating a constant temperature that the egg is needed for development. Heat is transferred from the mother to eggs with bare patch underneath her called the brood patch. The mother does not only heat up the eggs but cools them down and protects them from harsh sunlight. She will also turn the eggs in order to give heat evenly throughout. It is important that the mother is not away from the eggs for too long and when disturbed by humans or other distractions she is keen to quickly return to the nest. I have witnessed the mother flying around to try and distract people or intruders away from the nest with constantly soaring nearby making warning calls. The male will also join in on this distraction display if he feels that the nest or young is in danger. Also when if the pair feel they have been followed back to the nest by mobbers or potential preda46
tors they will lose them before returning as not to give away the location. When the chicks hatch and break out of their shells with a temporary adapted feature called an egg tooth it is straight away cleaned and ready for its first feeding. The Buzzard chicks are born altricial which means they need complete care when hatched as they are blind, naked and helpless as well as being susceptible to predators. The first couple of weeks the mother will stay with them at this vulnerable stage while the male will still hunt and provide food for both mother and chick. When the chicks are less defenceless both parents will then hunt providing the chicks with the food that is much needed at this period in their lives and the chicks will have no resistance to letting the parents know when it is hungry with calls and gaping wide open mouths. The Buzzards bring the prey back to the nest where they will cut it up into smaller bite size chunks that are more edible to the chicks and will do so for around 50-55 days until the chicks fledge. The young will stay with the parents for around 6-8 weeks after fledging where they still are learning hunting skills such as what to and what not to eat and where to find it. The longer the young stay with their parents the chances of survival to maturity is greater but the parents will eventually have to push the young out of the territory as they too will become the competition. The maternal instincts of the Buzzard are so strong that there have been cases reported of eggs from other birds being placed in the Buzzard nest such as from the golden eagle and has successfully fostered and raised the young and it growing having more Buzzard tendencies than golden eagle. This process is called imprinting and can also be related to Buzzards being raised by humans. Buzzards have also been guilty although rarely in laying the eggs in other bird nests such as was recorded in 1982 in Poland where Buzzards placed the eggs in a sea eagles nest and were raised successfully by the foster parents. The issue with imprinting is they put their breeding efforts in trying to attract the wrong species when looking for a mate. 47
The common buzzard has had a history of persecution and revival. It has had many obstacles to overcome in the last 200 years. The changing landscape of the British countryside would be one of them. With the ever growing amount of land cleared for agriculture has resulted in important pockets of forests for where the Buzzard roosts and nests but in turn has 48
left many open land for it to hunt. Today there are many open areas with small pockets of trees which allow the Buzzard to thrive as it especially does so well in the Cornish countryside where it can be seen on a regular basis. The Buzzard has taken advantage of agriculture in using the open land
Past Present and Future...
for hunting prey such as rabbits and voles but it can also be seen following behind a combined harvester picking out worms from the ground, a very unusual behaviour for a bird of prey. The use of pesticides in the 1950’s and 1960’s had a large impact on the Buzzard. The use of these organochlorine pesticides resulted in the in-
ability for the bird to reproduce. The Buzzards prey would accumulate the pesticides through eating grass and earthworms and then it would transfer into the Buzzard as it eats its prey and the way these pesticides worked meant that the higher up the food chain the more concentrated they became resulting in it being more harmful at the top of the food chain. 49
...Past, Present and Future... The threat was not necessarily killing the Buzzards but when reproducing the eggs laid would not form properly and the shells would be too thin and not be able to support the contents. Birds played a major part in awareness of these pesticides as they could theoretically harm humans if the birds were being harmed so a ban of these pesticides in the late 1960’s took place and the Buzzard quickly bounced back from this threat. During the same time the myxoma virus hit Buzzards food sources hard. It didn’t affect them directly but infected rabbits with myxamatosis resulting in declines of rabbits as it killed a high percentage during this period. The death of these rabbits did bring light on what the Buzzards main food source was as many farmers persecuted them because they were believed to be killing game birds and livestock. One of the greatest threats to the Buzzard is due to illegal killing, which has dwindled their numbers to such an extent, that they have in the past been completely eradicated from many counties across the UK. This again came down to erroneously believing that they along with other raptors were cause of stealing wild game
and livestock although in the Buzzards case this was very far from the truth. It has been found that killing of such birds such as pheasants and grouse by Buzzards is very minimal and is a very low part of the birds diet. Laws have been put in place to protect raptors in the UK from illegal killing but it still takes place in parts across the country so these executers need to be educated in order to realise that birds like Buzzards possess no threat. Today illegal killing of Buzzards is very minimal, the use of harmful pesticides are almost non-existent and eradication of the myxoma virus in most parts means that the bird of prey can be now found in every county across the UK and is on the rise. It is a true success story and can be seen soaring most of the countryside skies as it has now overtaken the kestrel as Britain’s most common bird of prey. The RSPB has estimated in 2000 that there are 31,000 to 44,000 territorial breeding pairs in the United Kingdom. The future looks bright for the raptor and if illegal killing can be completely eradicated and habitats protected then the common Buzzard will truly be common again. 51
...Past, Present and Future 1800 - Buzzards bred throughout the whole of the United Kingdom and Ireland
1875 - Widespread killing resulted in the Buzzard being confined to western parts of Scotland, England and Wales
World War 1 and 2 – Buzzards make a comeback due to reduced illegal killing
1950’s and 60’s – Rabbit populations decimated my myxamatosis reducing a vital food source so numbers decline. They were also affected by organochlorine pesticides, which reduced their ability to reproduce 1960’s and 70’s – Pesticides that harmed the Buzzard were withdrawn and illegal killing was reduced so numbers slowly started to increase
1990 – The rate of acceleration increased more rapidly and re-colonised the south and east of England and Scotland.
2000 – Numbers keep on growing over the decade to a healthy population with estimated number of territorial pairs reaching 31,000 to 44,000
Today - They now nest in every UK county and is Britain’s most common bird of prey overtaking the kestrel
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Population Trends from 1800 to Present
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Falconry and Buzzards...
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Set in the lowland Cornish countryside at St Columb is the family run Cornish Birds of Prey centre which is home to the largest collection of Predatory birds in the West Country. I travelled from Falmouth to the centre about an hours drive away where I was welcomed by Andy Grigg the centres Falconer. Andy Grigg born and raised in the Devonshire countryside was handed his first opportunity at falconry when he was 12 years old which was the spark for his passion for birds of prey where from then on became a key hobby which resulted in the business he runs with fiancĂŠ and family today.
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...Falconry and Buzzards Talking to Andy we discussed what it takes to care for a bird of prey and what it took to become your very own falconer. He mentioned how easily it is to get hold of birds of prey through captive breeders and that this was a bad thing because there is no licenses for owning your own bird so without the right education and training could result in escapes, neglect and poor health for the birds or in serious cases attacks on humans. With the right education, training and qualification as well as the right facilities then falconry can be made possible and safe which at the centre you can see exactly what it takes to care for these birds of prey and a quote from Andy says “You don’t own a bird of prey you care for them”. Andy will only breed for the centre and for his shows but has no breeding programme. He says he will not breed for friends or profit as it is important to keep these birds safe and properly managed. When he does have new chicks at the centre he goes two ways of raising them, either hand rearing (imprinting) or allowing the parents to raise the birds depending on what he wants out of the bird. The centre is residence to about 37 species of bird including around 10 species of owl, many falcons, raptors, hawks and many more. This includes three different 56
species of Buteo or Buzzards including a Common Buzzard, a 30 year old large female called Ruby. I have been conducting a study of wild Buzzards and asked the difference between captive and wild birds. Andy pointed out that captive birds live a lot longer because they can be treated for injury, disease and sickness, as well as having a constant supply of food and water. The wild Buzzards may not live even half as long as the centres Buzzard Ruby for these reasons as well as threats from other birds through mobbing such as crows, gulls and other birds of prey. He also mentioned the success story of wild Buzzards in the Cornish countryside as they can be a frequent sight in the skies because of factors such as layout of the land, road kill and other carrion as well as the growing numbers of prey such as rabbits and voles. After speaking with Andy I attended one of the flying shows he performs each day where the first one at midday saw him flying an American kestrel, European Eagle Owl, a Tawny Owl and a Peregrine Falcon. During these displays Andy teaches the spectators about the birds such as what they hunt, their natural environment and behaviour and will answer any questions about the birds. The shows are very fun, interactive and educational and would suggest everyone to experience for a very enjoyable day out.
References The Birdwatchers Handbook Paul R. Ehrlich, David S. Dobkin, Darryl Wheye, Stuart L. Pimm Oxford University Press 1994 ISBN: 0-19-858407-5 Birds Britannica Mark Cocker, Richard Mabey Chatto and Windus 2005 ISBN: 0-701-16907-9 Eagles John A. Love Whittet Books 1989 ISBN: 0-905483-79-0 Collins Bird Guide 2nd Edition Lars Svensson, Killian Mullarney, Dan Zetterstrom Harper Collins 2009 ISBN: 978-0-00-726814-6 A Climatic Atlas of European Birds Brian Huntley, Rhys E. Green, Yvonne C. Collingham, Stephen G. Willis Lynx Edicions 2007 ISBN: 8496553140 RSPB http://www.rspb.org.uk/wildlife/birdguide/name/b/buzzard/index.aspx March 2nd 2011 Arkive http://www.arkive.org/common-buzzard/buteo-buteo/ March 4th 2011 Scottish Natural Heritage – The Common Buzzard March 10th 2011 http://www.snh.gov.uk/docs/A253112.pdf Dr Andy Douse
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