Sunday, January 27, 2013

A bat in the hand

One of the first discoveries having arrived at UKZN in Pietermaritzburg in April last year,was the roost of the Epauletted Fruit bats right here on campus.  Its such a novelty for a Kiwi, to have big bats so close to home and work.  Infact Prof Downs was recollecting a story about a lady that worked in her office right against the roost tree.  She had to work with her curtains closed because she was uneasy with the bats constantly staring at her with those big beady eyes all day.  Personally I would move into that office right now given half a chance!

An MSc research project was completed in 2012. "Seasonal home range and foraging movements of the Wahlbergs Epauletted Fruit Bat in an urban environment." By D P Rollinson.  The bats were fitted with transmitters and followed on foraging expeditions.  The research was wrapping up when I arrived in April, and while bats were being recaptured to remove the transmitters used in the study,  sadly I never managed to get involved at that time.

Fortunately new research is beginning on the bats that use this roost. Providing an opportunity to get in amongst it. Dr. Lorinda Jordaan is hoping to catch a few bats every month. The longitudinal study will focus is on the bats breeding cycle, and in particular on the aromatic compounds secreted special glands on their shoulders that give them their namessake - epaulettes.

This last weekend was particularly successful, we caught four on the first night and six on the second. Getting an opportunity to get up close, extract them from nest and handle them in the lab, it was a real buzz. Swabs of the epaulettes were taken and then the bats were weighed and released.

Fruit bat roost tree

The flyway interceptor

Prof. Colleen Downs extracting a bat from the net

Released after sampling

Friday, January 18, 2013

District Monkey

After such an amazing month of fieldwork through the summer solstice, the pace and focus has changed dramatically. If there is ever a time to be office bound than the Pietermaritzburg summer isnt such a bad time.  My office remains in the cool 20's while its a humid 34 degrees (or more) outside.

I have been wading knee deep in literature and reference material while attempting to write my introductory chapters.  And this is set to continue for a few more weeks yet. This project has turned my attention to urban ecology. And moreso, the significance of urban wildlife as a source for the majority of the human-wildlife experience - as of 2008 more than half of the seven billion people on earth are urbanites.

The most highly modified places, the urban core is such an unfamiliar place for wildlife.  The concrete jungle, tarred and sealed surfaces, and buildings of brick and glass - yet pigeons and peregrines have no trouble making use of these human made analogs to their natural cliff habitats. There are just a small range of these urban exploiting species, but they can occur in great numbers.

Towards the suburban and peri-urban areas the structures decrease and the landscape is tending towards a mosaic of green-spaces (parks, reserves and buffers) and residential areas with gardens trees and lawns. Much more acceptable for animals of more typical forest and woodland areas, and these areas have the riches variety of urban adapting species.

Hazards abound in the form of speeding vehicles, electrical networks, fences and of course people.  It is actually surprising at how many species are able to adapt to urban environments, and Durban is blessed with variety. Thats for sure.

As the biology of the Crowned Eagle is viewed through the lens of urban ecology, there is much to consider about the eagles impacts and effects on the local communities; both wildlife and human.  And I am now looking at a number of complex interrelationships, predator and prey, the preys prey, disease transmission, and human dimensions of percieved relationships.  A few species thriving in the urban areas, hadeda ibis, dassies, and monkeys to name a hattrick of eagle favorites  All have their particular conflict issues.  Hadeda's are those flying vuvuzela's, forming rowdy roosts, and picking open garbage bags on collection day.  Dassies, well those little rock rabbits are apparently pretty benign, I dont hear people complain about dassies.  They seems to do well, forming colonies in storm drains, culverts, and rock banks. But monkeys...


Monkeys tend to polarize communities. Their intelligence and character can work in their favour, but their ability to use that intelligence for mischief is the origin of a lot of animosity.

I like monkeys, they are inquisitive and adaptable, and they provide valuable protien for the most magnificent predator around here.  But I have also been the victim of monkey burglary.  And I have a particular sore memory of having a delicious moist christmas cake, prepared as a thankyou gift for our December house-sitting in westville, devoured in minutes, right there on the kitchen bench, while Patrick and I were watching our eagle trap out in the lounge.  Cheeky sods.

Before I harp on about what they do, and what they dont do.  I would just say that I was doing a web search for more information on issues around 'the urban monkey'.  I found this.  I haven't had a chance to watch the series but the trailer gives you an idea of some of these urban wildlife conflict issues.

Sunday, January 13, 2013

Tech Joy

2013... it was about time for some new equipment.

First and most importantly being a new laptop!!!  With 250,000 nest camera photos, in folders of 10k images each, the strain on RAM and graphics is demanding.  The Acer netbook is going on four years old, and while compact it seriously struggles to keep up with timelapse analysis.

So I walked in to the store with my harddrive full of photos. Plugging it in and sampling their abilities of the various units.  I managed to hang an Apple Macbook pro with my first trial.  Then went to the PC laptops, and along to the end of the shelf, where the Samsung behemoth sat proudly beside its spec label... and pricetag.  Eesh.

But it was barely started, still in the process of installing Chrome, Skype, Googel Earth, and other useful apps, when I discovered the Movie Maker.  A quick exploration with two sequences I was familiar with and I came up with these results.  Pretty happy!  Animated sequences like this will be very entertaining for talks and presentations, and give you an appreciation for the quality of the data that will be used to analyse nesting behavior and diet.

But thats not all.  I have been waiting for baited breath to get a new camera.  Thrilled to have purchased the Canon SX20 when it first came to the market in 2006, the 20x zoom was the leading point and shoot camera I could find.

This camera tolerated my abuse, and being a permanent fixture on my travels and fieldwork, it gets subjected to all extremes of weather, and some hard knocks.  It was still working perfectly when the SX35 came out, and so it was difficult, but somehow I managed to resist upgrading back then.  Ever since I have been holding my breath for the next big thing.

Canon Powershot SX50.  Thats 50x zoom lens equivalent to 24-1200 35mm.  And with digital zoom it can pull 100x zoom! Phwoar!  As soon as it hit the shelves I had one in my sweaty hands.  Delightful...

The camera sat in my bag for a few days, waiting to christen it with something relevent and important.  That chance came with the autopsy of our shot eagle.  I was particularly happy with the xray photos.  The next chance was a little time-out in my park - and managed to get a few nice pics here.

To complete the trilogy of tech enhancements, the purchase of a new phone was necessary.  Months ago I was given a old hand-me-down Nokia.  Welcome to the 21st century kiwi, a phone with internet access! With a camera! I quickly found these features enhanced my work efficiency. Answering emails in the field, and taking photos of chicks while at the nest.

The old Nokia cant swim, I found that out recently.  Pity...  A replacement was needed.  So I hope the Nokia C7 will be as durable, welcome to the family, and the school of hard knocks!

The very last photo from the old Nokia

Self portrait!

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.

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.

John Carlyon, Clarendon Vet Clinic, extracting the pellet

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

Sunday, January 6, 2013

Peak Season 2012 - Introduction

Reflecting on an amazing month of fieldwork , I have finally found my way back to the cool air-conditioning of the office.  This one blog is the prelude to a mosaic of events popping around. Follow the link in text to jump to pictures and expanded stories.

Ultimately all the activities revolve around the culmination of the eagles 2012 breeding activities.  The season has been surprisingly synchronized among many nests, and they are all now preparing for their imminent first flights.

The primary focus being on timing and accessing nests to ring this years nestlings during this critical time.  Blogs also include photo documentaries of ringing at San Lameer and Victoria Country Club nests.

Nest cameras have been operating superbly, and all five nests including the Victoria Country Club family are going strong and thriving on urban prey

A batch of advanced GPS data loggers were received, and much time and effort spent in trying to deploy these on adult eagles for home range studies.

All the while, I have had the pleasure of having amazing assistants during this time.

And for a few weeks in December, a lekker field base to work from.

And finally to wrap up an earlier post in December.  During the latter half of the month, my eBird big-month began to suffer and slow down.  But nonetheless I finished the year with a respectable total.

Heres to an exciting 2013! Cheers!

Ringing the 2012 Cohort

In order to be able to follow individuals birds and their life history, they must be uniquely marked.  This is a key component for the population studies, and especially following the dispersal and survival of young birds.  

Marking involves both SAFRING identification rings and plastic CB rings, which with their bright contrast and large codes allow much easier recognition and reporting of individual eagles in the field.  The nestlings must be ringed within a specific time frame; to be fully or near-fully grown to fit the ring well, but not so mentally mature to think they could jump to escape this approaching monster.  Fortunately we were able to age these birds well and time the climbs appropriately, ringing eight between December and early January. Ringing juveniles and nestlings are particularly valuable because we know their age and origin, and could provide some very interesting longevity and dispersal data in the decades to come.

The behavior of the birds is very interesting.  I had expected more aggression from the adults, such is the need for a riot helmet and foam filled backpack.  Fortunately all birds appeared reluctant to attack.  Two nests that I have accessed have involved birds that were prepared to frighten me by a flyby within about five meters.

The nestlings generally show a threat display as they first see me broach the edge of the nest, facing head on with mouth agape and wings outstretched.  However as I climb further they may realize just how massively outsized I am, and their next response is to go completely catatonic. This is very fortunate in that I can place a bag next to the bird and simply lift it across, zip up, and lower it down.  The young eagle is kept in the dark and hooded while still in the bag.  They generally remain calm and docile while hooded, even during all the handling and measurements.

Our procedure has been well practiced now, and although the time it takes to get a rope in a good position for access can vary greatly, the process of removing the chick from nest and back takes all of about 20-30 minutes - depending mostly on the height of the climb back to the nest.

*awaiting more photos of nestlings and nests*

Ringing at San Lameer

Photo documentary by Jacques Sellschop.  (c)

Setting the scene. The nest is very visible from San Lameer main entrance

While setting up the climbing rope, food was delivered to the nest

She was nervous about all the unusual activity and startled as the rope was pulled over

Arriving at the nest the young eagle is all threat display

Very quickly she goes catatonic with fright. Fortunately it makes collection and descending a safe procedure

First moves at the ringing station

unpacking the equipment and readying the bird

closing the SAFRING

Taking a tarsus measurement and color ring Y8

Taking a head measurement

A part of the gathered crowd

The heat and humidity at 6pm was surprising

A larger perspective of the gathered crowd

Tail feather development

Primary wing feather development

Taking a drop of blood for DNA sexing

Final measurement - mass

Identifying the prey that was delivered earlier - a young hyrax

Beating a hasty retreat after returning Y8 to the nest

Happy with the result!  Within minutes of my descent the nestling was feeding on the young hyrax

Ringing Donna

Thanks to the three photographers who contributed their photos to the blog

DB - Derek Brittain
GDW - Gustav de Wet
JA - Jack Alletson

Boxing day ascent.   JA

Victoria leaves the nest to watch from nearby.   DB

Composite of 'bagging' the bird.   GDW

Derek Brittain in action.   JA

Out of the bag.   DB

Measurements of the head after ringing.   DB

Taking a DNA blood sexing sample... Donna?   DB

Measuring mass.   DB

Preparing to return Donna to the nest.   JA

The crew in action.  DB

Lifting the bag onto the nest...   GDW 

...and out of the bag.   GDW

And descent.   GDW