Thursday, October 3, 2013

Don the technophile

Don is one year old!  It has been an exciting journey following this particular eagle, made possible from the start by constructing a makeshift nesting platform.  Granted it wasn't photographically aesthetic, but the eagles liked it.  And Victoria and Albert soon had a nest they were happy to use. The little crowned eagle chick(s) hatched on the 8 October 2012.  Twenty days later the monitoring camera was installed, and from that point the nest activities were observed in intimate detail

100,000 images later Dons development, and all the food he’d consumed in 5 months, had been recorded.  He fledged from the nest on 19 Jan, and has been tended to by his parents all this time.  We are not sure if he’s managed to hunt successfully yet, but his dependency is now lapsing its first year.  Recently some aggressive confrontations between the queen of this realm Victoria, and son Don have suggested he’ll soon no longer be welcome at home.  Sometime between 7 and 13 months old the young crowned eagles will be ousted from their parents’ territory.  Its time to travel the world, become self-employed and eventually invest in the housing market.  Don may have a tough time establishing a new territory; a raptors survival is most tenuous in its first few years, and he'll have to face many challenges.  It will be about four years before he’s man enough to breed himself. 

How far and for how long crowned eagles roam is still not clear and so, with the support and financial support of the Victoria Country Clue Estate management and residents, and the technology, knowledge, and advice from Ben at Raptor Rescue, we have been able to fit an Avi-Track solar-GPS telemetry unit to Don. Weighing 70 grams, it is 2.2% of his weight, while bulky, the box dimensions have to be tall to capture enough sun over his back feathers.  While these units have been used effectively on vultures, and many other large raptors, crowned eagles spent much of their time in the shadows of the forest so the solar powered units are going to be tested to their limits.  

The dispersal data that we record from Dons movements will be aiming to answer many still unanswered questions about the crowned eagles sub-adult years.  And most importantly we will be able to respond quickly to any suspected inactivity indicating injury or death.  Five juveniles born in 2011 were killed by various causes including a pellet gun, and three electrocutions.

Ferncliffe, where Don was captured on 26 September.  Photo Burkhard Schlosser 2013

Don showing interest in the trap.  Photo Burkhard Schlosser 2013

Ron Perks and Ben Hoffman assisting with the project.  Photo Burkhard Schlosser 2013

Threading the Avi-track GPS unit.  Photo Burkhard Schlosser 2013

The makeshift field lab.  Photo Burkhard Schlosser 2013

fitting the solar powered GPS - GSM device. Photo Burkhard Schlosser 2013

Fitting the harness.  Photo Burkhard Schlosser 2013

biometrics: inner talon 52.4mm. Photo Burkhard Schlosser 2013

keep clear of the pointy end. Photo Burkhard Schlosser 2013
Preparing to weigh Don, at 2,700g he is fit and healthy.  Photo Burkhard Schlosser 2013

Taking the hood off a few seconds prior to release.  Photo Burkhard Schlosser 2013

Lift-off.  Photo Burkhard Schlosser 2013

Up up and away.  Photo Burkhard Schlosser 2013

and cruising back to his perch for the evening.  Photo Burkhard Schlosser 2013

Its been time-consuming this week.  With GPS positions appearing on a private webserver exactly on schedule three times a day, I chased a few morning and noon fixes.  Its already dark by the evening fix, when Don should be settled in to roost, and finding him then is difficult.  Finding him anytime is difficult, but I did manage to hear him twice from the vicinity of the GPS location.

We watch in anticipation for Dons next move, maybe he'll leave soon, or he might even stay until this time NEXT year, when the Victoria and Albert will hopefully breed again and kick him out for good.  So it time to wish Don well for this next stage of his life.

Sunday, September 15, 2013

The Black Eagle Project

So here I sit at Ashanti Backpackers in Cape Town.  A grey windy and wet day to write while passing the time, reflecting on the last ten days of bliss.  This was a self-inspired trip to visit TheBlack Eagle Project, PhD research initiated by Megan Murgatroyd.  Megan is now in the third field season of research comparing land use and productivity of the (relatively) pristine population of the cederberg Black (nee Verreaux) Eagles, and the eagles of the Sandveld which are living next to lands with extensive agricultural transformation.

On the 6th of September (happy birthday to me!) I flew from Durban to Cape Town, and boarded an evening supersonic taxi to Clanwilliam.  Megan met me here at 10pm and we began the hour-long drive to the field site, the gravel road endlessly evolving in the headlights.  Arriving at night meant I had no idea what landscape to expect in the morning.  On the first frosty dawn, the sun peaked over the eastern mountains and slowly warmed the valley.  The field house is part of the Driehoek farm, passionate sponsors of Megan’s research and, surrounded by the Cederberg Wilderness Area, perfectly situated for access the study site.  Driehoek is a great place to set up camp on one of their camping/caravan sites if you’re inspired to come and visit.

Spring comes to the cederberg now.  And the flowers were beginning to bloom.  To the south the fynbos dominates, and to the dryer northern slopes different colours representing succulent karoo. Mountains loom over the colourful valleys with tiered expanses of cliffs and crags providing an abundance of nesting opportunities for eagles and other raptors.  We spotted plenty of kestrels and booted eagles, and despite their absence no doubt the cliffs would be full of peregrine and lanner falcons as well.  In the river valleys, reed beds provide all that a Black Harrier would need, and the old oak trees around the homesteads also home to a Black Sparrowhawk.  I noticed a theme here - so I dressed in black every day - there must be some reason it works so well for mountain raptors.

While most of the nests in the cederberg have not bred this year (for reasons to be determined), we set out each day for short walks to nearby nest observation sites.  Invariably each site had some sort of eagle entertainment to watch.  On one occasion during the 1 hour watch, while being amused by the wing-flapping exercises of the eyass, the pair of adults appeared over the top of the ridge.  While one adult descended to the nest site to deliver fresh prey to the waiting chick, the other coming from an unknown location, tucked into a steep glide, building up speed and rushing by just 30 meters from us, before continuing out over the deep valley beyond.  At another site, the pair cautiously checked these bipedal intruders into their territory, drifting back and forth in front of the nesting cliff in the most majestic style before coming to perch together on a distant ridgetop buttress.

Three active nests were visited, including one that was a new discovery for the season – a site that takes an hour of bone-rattling driving and then a short hill hike to get to.  The bakkie ‘Ratel’ has done some rough miles over the last few years, and there have been countless flat tires to fix.  It takes guts and mettle to face these boulder strewn slopes, and trek miles through them day after day searching for nests.  And mettle Meg has in spades, attested to by a titanium pin, the result of a compound fracture while boulder hopping a stream early on in the project.  To strengthen the ankles again and blast through another two seasons is testament to the determination and passion for the Black Eagles.

Ratel in the karoo blooms

I battled to get far enough uphill of Meg to take this perspective shot

Happily, there was something useful I could help with.  On day three we set off early towards Tafelberg, the second highest summit in the range.  Up on the last plateau before the summit sat a VHF relay station to download GPS tagged eagles - this had been pounded by recent storms, the unit was silent and the aerial broken.  So after a 2 hour uphill hike (passing a lifer, a pair of Cape Rockjumper’s on the way), we reached the base station, stopped for lunch, admired the scenery, and then loaded the equipment, Megan with the batteries and downloader and I with the 9 ft aerial, descending back to the field base.  A few days later I was to get another remarkable perspective of Tafelberg peak.

For some weeks Megan has been preparing to repeat the helicopter surveys that proved so successful last season.  The 2012 helicopter surveys were in November, when many nest had fledged, this year the surveys were timed earlier to be able to locate the nests while chicks were still at home. Unfortunately, September surveys coincided with the aviation students’ exam time, and there were limited numbers of pilots and budgets available to fly the crags of the cederberg, cutting down on the previous years available flying time.
On Wednesday evening, the two two-seater R22 ‘matchbox’ helicopters arrived.  They were covered in their blankets for the night.  The sun peered over the ridgetops the next morning and gradually softened the frost.  But the helicopters were hypothermic after such a cold night.  Theres something disconcerting with helping jumpstart toy helicopters that we’re supposed to be airborn minutes later, moreso when one of them refuses - having blown some electrics around the solenoid or alternator.  Without power for the radio’s and gauges the pilots decided that it should stay grounded until the flight back to cape town airport. So down to one helicopter for the survey.

Happy with the jumper leads, the second chopper roared to life, and the first flight was up and out by 9am. Megan logged four flights, surveyed 28 nests, and added three new nest sites to the known population!  Incredible success for five hours airborne.   Then as 4pm rolled around, there was one hour left before sunset, the chopper refuelled and Megan offered me an opportunity to fly a transect.  Taking a direct line over the Tafelberg neck where days ago we’d hiked 2 hours up the mountain, in 7 minutes we crested the ridge, and descended to the other side, passing the Die Hoek nest site that takes over an hour to drive to.  Passing over a waterfall, another plateau and then into a cavernous gorge on the Tra-tra River.  After taking several runs at gps marks on tiered cliffs, it was quickly apparent this was no walk in the park – despite being just tens of meters from the cliffs. Eventually, I spotted one of the sites, apparently recently used but definitely empty.  And all too soon with fuel and sunlight running out it was time to turn tail and head back over the ranges to base.  We passed by the Tafelberg neck again just as the setting sun poured red light over the rust coloured rocks.

The following morning, rolling clouds and high winds forced the pilots to beat an early departure from these changeable mountains, flying in tandem back to CapeTown so the bird with the radio’s could get ground clearance for the crippled craft.  Meanwhile Megan and I walked to Uilsgat Rock to sit under an old bushman shelter, with weathered rock art, the old bushman's shelter was a great place to chill and maybe see a pair, despite an inactive nest this year.

After eight days of blue blue skies and softly winds, yesterday morning I woke to the rain streaking sideways across the valley.  Time to hitch a lift back to Cape Town then.  The week has given me a very constructive time to discuss all thoughts of eagles, the trials and successes of the research.  The environments our respective eagles call home definitely determine much of the rest of how the research plays out.  And I find myself somewhat envious of Megan’s remote little mountain paradise (inspiring landscapes, melt-water streams, pure fresh air), while also appreciating the benefits of urban research (smooth roads, passionate public participation, and access to… well civilization).  Now I’m looking forward to getting home to the crowned eagles to perhaps see the first hatched chicks of the season.

Cederberg Microcosmos

There are just too many great photos to put in one blog
Its the little things... that really matter

Monday, August 26, 2013

White Umfolozi Rocks

The progression from tree-climbing, a utilitarian need, to rock climbing as an adventure sport has now progressed to a dedicated long weekend trip.  I can see this developing into an institution!  Its just so damn good

I was offered to escape on a long weekend into the depths of Zululand.  The mountain club have been enjoying this beautiful spot on the White Umfolozi river for many years.  Nestled in a valley is a quaint little campsite just minutes walk from four large faces with untold sport and trad routes.  In passing Hallam mentioned that Crowned Eagles are occasionally seen flying over, many years ago there was a nest near the old hut – but perhaps we could trek to search for a new nest location

As it happens, before sunrise on the first morning, I saw a crowned eagle fly along the cliff face and get stooped on by a pair of lanner falcons - soon after the juvenile showed up.  Obviously still quite dependant on its parents for food, and obviously quite hungry, on following days the morning coffee was always accompanied by the incessant, piercing begging calls amplified and echoing through the chasms

A bird list of over 40 species on the three-day trip includes plenty of lapidarian names:
mocking cliff-chat, rock pigeon, rock-loving cisticola, cape rock-thrush and a few rock martins among the swarms of cliff loving swifts,.  The raptor list starts with rock kestrels, with a variety including lanner falcon, brown snake-eagle, white-backed vulture, gymnogene, gabar goshawk, and the crowned eagles.  Pretty impressive but lacking the hopeful expectation of a verreaux eagle


the power wall

klip kloof nestled in the valley

idyllic camping style

rock kestrels

insistent juvenile eagle

Rock climbers are imaginative with the names of their sport routes and trad lines. Puns aplenty and many unsubtle references. On the first day a lot of easy routes were tackled, almost completing the Bushy Buttress face
Aardvark (8) on sight
All Aboard (9) on sight
Adios Amigo (14) on sight
Abdominal Noman (13) on sight
Yeti (13) on sight
Little Honda (12) on sight
(16) Going on 17, **** an intimidating looking set of roofs that turns into a very pleasing ascent, top rope
Happy (13) on sight
Oink (15), on top rope and then busted for the day

Although the forecast predicted a 30 degree saturday, the chill of a fast moving cold front kept the temp shivering cool in the shade of the Warrior Wall.  So after a few quick ascents including
Bird Child (16) top rope
We headed back for coffee and to warm up.  As the sun arced high a plan for a duel-purpose eagle / geological adventure evolved.  It was straightforward to find the eagle nest in a kloof feeding a tributary to the main river.  Marveling at the rocks was all the more interesting by the aid of a small leaflet from recent university geology surveys highlighting the main points:

considering renaming Bird Child to Three-way

going on 17 (16)

the first four bolts looks... complex

eriosion patterns

banded iron formation

The area is apparently formed of a variety of rocks in the Pongola Supergroup. The basement strata are old pink and white granites.  On this, sandstones and shales are interrupted by basalt pillows formed in underwater eruptions of lava.  And on top of these layers lie sandstones and dolomite which are particularly famous.  The 3 billion year old rock includes some of the oldest fossils of life - stromatolites created by mats of algae in the shallow seas.  Then after this, the Banded Iron Formation, which forms in deep water as muds slowly settle to the seafloor.  Prior to 2 billion years ago the atmospheric oxygen was much lower, and fluctuating.  When the iron rich sea’s encountered peak oxygen levels, the iron precipitated and formed banded layers in the sediments.  Oxygen levels are too high for Banded Iron Formations to form anywhere on todays Earth.  The youngest rocks of the Pongola Supergroup are 2980-2870 m.y.old and at the river these form pavements of blue/grey rock with intricately preserves ripple marks

An unconformity then separates these famously old rocks from the tall walls of sandstones that are only millions of years old; these are the rocks that fulfil all of the climbers’ desires

The left bank of the river is cast in afternoon shade, and on The Promised Land two great climbs completed the day
Chicken Wing (13) on sight
Freckles (14)

During the afternoon Hallam managed to scope out a new route, so we returned Sunday morning to set it up.  After hours of drilling and bolting, the new route was opened by Hallam.  I dogged my way up at the limit of my ability, using a small tree and a skinned knee to ungainly beach myself onto a ledge.  The route is thus named Treason Knees (18)

starry nights and meteorites... a grand way to end a story about rocks