THE URBAN CROWNED EAGLE This blog follows experiences and events throughout the course of my research while based at the University of KwaZulu-Natal. This MSc research is focusing on the ecology of urban Crowned Eagles. How do they survive, even thrive, amongst the urban environments of Durban and Pietermaritzburg, South Africa?
Showing posts with label Persecution. Show all posts
Showing posts with label Persecution. Show all posts
Tuesday, July 30, 2013
Sunday, April 28, 2013
Thursday, January 10, 2013
Obituary Number One
On the 12th of December I answered a phone call from the SPCA in Pietermaritzburg. They had just received the still-warm body of a Crowned Eagle from a distraught local. I arrived at the SPCA soon after to collect the remains, my heart sank. The bird seemed in fine condition, mottley with new feathers molting through, powerful and clean talons, and plenty of muscle on its breast. A little blood oozed from a tiny hole near the lower jaw. We surmised it was shot and immediately sought to open an investigation with the police.
This bird was ringed. I identified it as a juvenile that I caught near its Clarendon nest site on the 25th of July 2012. That day, we waited until the kids in the park left the area, then set a trap and quickly had her. I restrained the eagle while Minke ringed it, and we had assistance from the Clarendon Veterinary Clinic staff. This was the second only to be ringed for the entire study, we were full of nerves and excitement and looking forward to following this character on a long life laid out ahead of her. I released the bird once we'd ringed and measured, and the photos were featuring on the UKZN homepage for a while.
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| in July 2012, at nine months of age, a beautiful juvenile eagle |
| in her urban home she became accustomed to the presence of people - these lightys respected that |
| A camera trap deployed whilst trapping this eagle |
It is the first ring recovery from my study. And casts a dark shadow over the impression that these eagles are thriving in the city.
Shot in the head with a air rifle.
During the winter of 2011, the resident adult pair repaired their nest and laid their egg. The residents around the Clarendon nest site watched with anticipation. Hatched in October 2011, the chick flourished on prey the adults brought to the nest, mainly hyrax and Hadeda Ibis. It became extremely well known and popular among the residents and visiting photographers. Nearly four months later, on the 12th of December, the youngster made its first flight. It then stayed in the immediate area for another seven months, as these large eagles take a very long time to learn the techniques to hunt for themselves. Its insistent calling for food from the untiring parents made it a conspicuous and much-admired bird.
This eagle was one of the first to come to my attention, two months after arriving in South Africa to start the research. After ringing it in July, I kept my ear to the ground, phoning to receive the latest sightings and reports on the birds behaviour It started to wander, apparently hunting successfully for periods before returning to the nest area occasionally to try its luck begging for more food.
Eventually, on the 14th September 2012, this young eagle was heard calling from its usual spots for the last time. It was time to move out to a life of independence, to fend for itself and ultimately establish its own territory. This is the most dangerous time in a Crowned Eagle’s life, finding a place of its own, with enough prey to master the skills of hunting to avoid starvation. Indeed, as we now know, the young eagle succeeded in overcoming this obstacle to its survival - it had a full crop, probably a hadeda, and a long bone extending from its crop that it was apparently still in the process of swallowing.
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| John Carlyon, Clarendon Vet Clinic, extracting the pellet |
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| lead shows in an xray as a bright white blotch, the bone in the throat also shows on the xray |
The autopsy was performed recently, in the presence of South African Police, photographers, and an honorary officer of the Ezemvelo Wildlife Crime Investigations Unit. The ballsitic extraction revealed a .177 airgun pellet, a shamefully tiny projectile, lodged right below the first cervical vertebra. This was a well placed shot, a consolation that the bird did not suffer a painful and slow death, as many do when they have pellets festering in non-lethal parts of the body and limbs.
She travelled just seven kilometres from her place of birth, and survived just 15 months of what could have been a full 40 years of life. Wantonly destroyed in an act of criminal stupidity. Parents who provide children with dangerous weapons such as pellet guns should be made accountable for their actions. It is essential that these actions are met with the full force of the law.
Co-authored by John Carlyon and Shane McPherson
Friday, September 21, 2012
Human-Wildlife Conflict
- biodiversity threats: semi-feral cats and monkeys can become superabundant with the help of supplementary food and absence of natural predators. Their impact on birds and nesting success may be high.
- nuisance animals: racoons spread garbage while it waits for collection on the kerb
- disease risks: stray dogs and urban foxes are a potential source and vector of rabies
- health and safety: coyotes and eagles can threaten the safety of household pets - cats and small dogs that their owners have a emotional attachment to.
This last point is the topic of the day. Below is some information regarding a particular eagle that I have been following. It was infact the very first eagle captured and ringed for this project. The community is becoming polarized, some wanting to give the eagle full protection and let it live and disperse naturally, others (most of those impacted by attacks on pets) want it gone immediately.
Footnote: since sending this response I have had three different responses that the juvenile eagle was indeed offered food (viennas even- full of nitrates and additives). Those particular tenants have since moved on - and in their wake have left a legacy of a 'problem eagle'.
DO NOT FEED WILD ANIMALS
Sunday, June 17, 2012
Research Update #3 - mid June
Two updates in a month ?! So much going on and so much to
talk about. Introducing here a quick
update on the camera trial, eagle ringing, and more nest surveying, before delving
into the issue of population trends, persecution, and a visit to the museum.
Very briefly I will say that the nest camera trial has hit a
first hurdle – with the eagles proving their impressive strength and ability to
simply reject my intrusion. The camera was
ripped from its nest-site mount, lens pierced by a surgically precise talon,
and tossed to the ground. So a re-think
is in order. A sturdy encasement and an
extra meter or two distance from the nest?
I have made five attempts to ring another juvenile – and this
was the antithesis of the first which you may recall took but 20 minutes to
trap. This youngster is known to have
had an interest in the local monkeys, and the shop rooster – however nothing I
could do would encourage the wee eagle to a trap. There are at least four other juveniles in
other areas which I would also like to trap and ring. But I need a greater arsenal – and in between
the other main aims at this time I will be building a couple more trap designs
and getting crafty.
Networking, public submissions, and additional surveying has
continued. Several more nest locations
have been filtering my way. There are
now a surprisingly large number of pairs - about twenty current and recently
active nest sites in the greater Durban area.
Three more were added while I spent the day with Richard Mckibbin.
A very popular and well known nest site is that of the
Kranzkloof gorge, and visiting this site for the first time last Tuesday
revealed the most fantastic nest site: a solid nest in a huge Mahogany tree
leaning out over the kloof gorge, and with a perfect line of sight from a clifftop
viewpoint only 60 meters above. The
female had enormous feet, something I noticed well as she stood on a mostly
plucked prey, probably duiker, on her nest lined with green twigs – a positive
sign that this pair will soon lay an egg this year.
The population that I am studying seems to be thriving, all within
or surrounded by heavily populated areas.
Despite a few instances I have come across of local persecution – locally
the eagles are generally admired and protected.
It is important to recognize that this is an isolated bubble - circumstances
which separate this population from the majority of a wide African range from
west Africa across the Congo rainforest, and from Ethiopia down the eastern
edge of Africa to a southern limit at the Tsitsikamma mountains, South Africa. The bushmeat industry is a major contributor –
removing a great deal of biomass of their preferred prey of monkeys and
antelope. Hunters mimic eagle calls to hunt the monkeys, which respond by
approaching the sound to sight its nemesis.
The territorial eagle also has a similar response and may approach this
unseen intruder- only to succumb to a gun or arrow. More widespread ecological destruction can be
attributed to continued deforestation and mining of minerals in central Africa.
The IUCN Red List has published its 2012 revision, and the
plight of the Crowned Eagle has somewhat cautiously been recognized within its
ranks as a shift from Least Concern to Near Threatened – as a result of more
(but still rather limited) knowledge.
To continue with this morbid theme – I had the pleasure of
visiting the Curator of Ornithology at the Durban Museum, David Allan. David is still very much alive – animated even
– it is the ornithological collection I was referring too! The museum bird collection contains over
38,000 skins, of many brilliant and bright African species making it the third
largest collection on the continent.
There are several cabinets full of large raptors, including just ten
Crowned Eagle skins.
Sadly the most disappointing feature of the eagle skins that
I looked at was the prominent paucity of data on the collection tags. I was hoping to look at these skins and glean
several facets of information, particularly to identify the location and cause
of death.
While in the early days birders and collectors were out
there shooting masses of animals and harvesting clutches of eggs for private
and public collections, the times have changed.
The flow of specimens into museums has slowed considerably – despite it
being as useful as ever to have carcasses of ‘ natural’ deaths added to the
museum collections. I implore all who
have an interest in wildlife to not overlook these valuable specimens. Should you chance upon a freshly dead
specimen of an interesting species, pop it in the freezer and contact the
appropriate museum to arrange a cold courier to submit it. It must
have a data card with three essential items: The date, the most accurate
location possible (GPS position), and the collector’s name. Ideally any additional data should be added
like the cause of death if known.
One of the more poignant examples of the eagle skins at the
museum was the individual from the following news article – a female that used
to be paired with the male at the site of my current nest camera trials.
Sunday, April 8, 2012
Raptors and People
You may find this particular blog delving into grandiose explorations of they way in which I perceive the world; about the global impact of people, the way in which our ecosystems are being shaped, and the perceptions of and impact upon wildlife – so sorry about that. But more importantly it should help explain why I lead myself into this particular research project – over and above my fascination and reverence of the Crowned Eagle in particular.
Anthropogenic environments: Ecosystems which are created or modified to various extent by human modifications. In the broadest view, it seems the entire biosphere as increasingly anthropogenic. The changing atmosphere is the case in point. While the change in atmospheric composition is still modest, rising carbon concentrations are already having a measurable influence, one which will continue to accelerate. If runaway climate change forces humanity to implement one or several geo-engineering concepts it will be a stunning demonstration of the both the immense influence, and utter lack of control we have.
Anthropogenic modification is varied in scale and intensity of alteration. Take for instance here a GoogleEarth view of Denmark, a landscape which is almost entirely composed of three basic categories: agricultural, silvicultural, or human domiciles. The urbanization of Copenhagen is seen stretching out from the eastern coastal margin. All of the wildlife diversity that lives here does so because it is able to exist or exploit some part of this anthropocentric landscape. There is a respectable diversity of birdlife, but Denmark is one of a handful of countries to have no nationally endemic bird species.
| The island of Sealland of Denmark. |
A particularly fortunate example of a species’ exploitation of a changed landscape is the response of New Zealand falcon to a particular timber plantation in the central North Island. I assisted Dr. Richard Seaton during his PhD research on this falcon population. A research project which discovered that in this ecosystem dominated by a monoculture of an exotic timber tree, here lives the highest density of NZ falcon known in the country. Why should they thrive here when they are far rarer in native forests in the mountain ranges up and down the country?
Kaingaroa Forest is extensive – approximately 140,000Ha, and is sustainably harvested because it is divided into small compartments of uniform aged stands. Because of this mosaic effect (despite the monospecies canopy) there is good structural variation, with plenty of edges between various age stands. These edges allow understory plants to establish rapidly in growing stands. They allow birds which require mature pine stands for shelter and nesting to be nearby clearfell areas with booming populations of detritivorous insects. The birdlife is surprisingly rich, including an abundance of some NZ endemics struggling in native forests; whitehead, tomtit, and their parasites; long-tailed koel and shining cuckoo are particularly thriving. Clearcuts attract loads of insects and grasses seed in these first years, which inturn supports the most abundant birds in the forest, introduced finches like chaffinch, greenfinch and redpoll abound. And because of this abundance of birdlife, falcons can thrive, preferring to nest on the ground in clearcut areas. But why does it seem that populations of rodents and their mammal predators have a greater impact in native forests than they do here?
| Kaingaroa Timberlands from microlite. Copyright Richard Seaton. |
The NZ falcon in particular has the potential to be very adaptable to various anthropogenic habitats. But despite all the prey available in the agricultural and urbanized areas, why have they so far been unsuccessful urban colonizers? The Falcon for Grapes project in the Marlborough wine region provided some explanations. Despite promising signs that falcons have a significant impact of reducing grape damage by frugivorous birds, of over 21 falcons to have died during the course of the release project, less than 5% died of 'natural' causes. Most troubling is that 47% of the birds (and 80% of females) were electrocuted, particularly at transformer boxes, feral cats and hedgehogs were responsible for several nest failures, others succumbed to collisions with windows or cars, yet others were shot by dove or chicken keepers, and a few died horrible deaths from various poisoning incidents, from bathing in sheep dip to falling into open diesel barrels. (Fox, N. 2010. in Wingspan Journal Vol 14)
While New Zealanders try to nurture and promote the remarkable and often unique wildlife, arising from a long pre-history of isolation in the absence of mammals, a contradiction that this is also the nation with the highest per capita cat ownership rate presents a jarring realization. There is a disconnect between the way academics value biodiversity, and the way the majority of the public connects with nature (patting Tibbles on their lap while watching the telly). If a falcon should turn up at a chicken coop or dove cot, it is all too often shot. Even a surprising proportion of birders dread the appearance of ‘damn sparrowhawks’ at their garden bird-feeder.
Getting To The Point...
I treasure the ten weeks of fantastic travelling through South Africa last winter, and was overwhelmed by the incredible hospitality of the falconers, conservationists, and wildlife researchers who we spent time with. The mid-point of the trip was marked by a week-long staying with a Kiwi friend doing a post-doc at the Fitztitute.
There was a day in Cape Town that I cherish evermore. We had been invited by Dr. Andrew Jenkins to accompany him for a day around Cape Town for some pre-season monitoring of Peregrine Falcons. The story of the Cape Peregrines and their expansion into the urban environment is fascinating, particularly as each individual is colour banded and the population dynamics can be traced through the entire urbanizing expansion. The first urban peregrine pair started breeding on a cooling stack of the refuse station, and after many years of decay this tower was planned for implosion. The city council sponsored installing alternative nest sites for the peregrines and Andrew put up the first boxes on nearby chimney stacks in 2005. Within an hour of the demolition, with the smell of chordite in the air and dust still settling, the peregrines were copulating on their new nest box. This was the catalyst for urban colonization and boxes were put up at other sites where the peregrines could be better placed. Another pair attempted to breeding behind an air-conditioning vent of the Rondebosch Childrens Hospital. With the worry that these chicks would get cooked behind the vent, a nest box was attached to the building also, and these birds have remained here and have been extremely productive ever since. They have produced four raucous chicks every year for the past seven years, all the while showering the hospital entrance with plucked pigeon feathers and whining and screaming as the juveniles develop. Now the hospital pair has children, and grandchildren, breeding in other areas of the city.
The tolerance, and even reverence of these tenants by the hospital staff, and the infectious nature of their appreciation to many of the visiting patients and families is an example that ought to be emulated. It demonstrates that the appreciation of nature is innate, but there are many biases in the way we view wildlife. Most importantly, those biases can be shaped by a little information, or by the social context in which we share that appreciation of nature with others.
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| Rondebosch Childrens Hospital. The main entrance, peregrine nest boxes can be seen to left and right of the central brick facade. |
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| A Cape Town urban peregrine, this one photographed at the Centuary City Apartments. |
Dr. Jenkins gave me the first whiff of this project. As we talked about Cape Town peregrines, touched on the success of urban Black Sparrowhawks, and various other urban exploiting raptors. This was striking a chord with my underlying tendencies for research interests. Andrew suggested I speak with Dr. Mark Brown at the University of KwaZulu-Natal when we got to Durban.
Having been invited to stay with Bruce Padbury in Hillcrest, we sure had an eventful few days. Bruce had already organized for a UKZN Masters student to come and capture some Black Sparrowhawk fledglings for her study, which led me into climbing a lofty Blue Gum in at the Pietermaritzburg Police Station to install one of her nest cameras. I did get to UKZN and bailed Mark up in his office, my eyes lit up when the topic of a study on peri-urban Crowned Eagles came up. Sure enough, back in Hillcrest the next evening while we were wandering around the back section, a Crowned Eagle turned up, perching atop a nearby tree and, very purposefully looked down her(?) nose upon us. This was the first wild CE I had seen. Spectacular!
| Hillcrest Crowned Eagle on the Keep |
| Close up with a great view of those hallux talons! |
Some months later and I have developed a research plan, secured enrollment and study visa and today I sit, all packed and waiting to fly out to Pietermaritzburg tomorrow!
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