Thursday, June 28, 2012

Summer Solstice

In the Nordic lands, the solstice is marked by the night of Sankthans – midsummer is celebrated by a mighty bonfire topped delightfully with a burning witch.  Actually, despite the visceral European history of burning witches at the stake, the reality is that the burning figurine is a symbolic gesture of driving away the evil spritis.  The Solstice is filled with magical forces of nature, good and bad.  Herbs picked and remedies made on this night are particularly potent.

The five scoop waffle icecream topped with sugary foam and a flødeboller was indeed potent… And a perfect accompaniment to a grey and rainy dusk on a windy beach roasting against a big-ass bonfire.

Super Special with flodeboller 

The summer solstice in the northern part of Jutland, Denmark, sees barely two hours of twilight between midnight and 2am – the dusk is exceedingly drawn out after a 10.10pm sunset, and the dawn equally sluggish towards the 4.34am sunrise.  In between the wet and cloudy days there were a couple of beautiful days to bask in. 

The most northerly tip of Denmark is Skagen, terminating with the mobile sandspit of Grenen.  Skagen is famous as a bottleneck of bird migration, particularly large proportions of the raptors heading to Norway and Sweden pass through here.  Rather better to visit during the equinox seasons then?

Nevertheless paddling in the shallows where two seas meet were both Common Seal and a much rarer Grey Seal, of which there are less than 50 in Danish waters.

at Grenen
with one foot in the Skagerrak Sea
and the other in the Kattegat Sea 

Without embarrassing her too much – these pales in comparison to the simple pleasures of spending a precious week with Mia.  We had been reluctantly prepared for a long eight months apart – important work duties occupying her for the northern spring and summer, only planning to arrive in South Africa in September for the Crowned Eagle field season.  All thanks to Mias employer who made a very thoughtful gesture as an appreciation of her hard work this season – this short trip has made the next ten weeks seem not-so-unbearably-long.

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?

a very suggestive pose - this pair has been mating frequently in the last week

smashed lens

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. 

the untrappable juvenile

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.

Richard and I at the upper Kranzkloof nest

particularly impressive feet!  sorry for the grainy photo

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.

one of the raptor cabinets

Crowned Eagles

[no data]

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. 

The Witness - January 1997

Sunday, June 10, 2012

Raptor Ringing Bonanza

The 7th of June is a day to remember.  Raptor Ringing.  Can having this much fun really be considered work, research, and training?  I can only hope it will become a monthly institution.  Our fantastic four, headed again by Mark Brown of course, travelled a 200km circuit of the Karkloof to count, trap, and ring whichever raptors were en route.  Typically roadside raptors, of the sort that drop on to their rodent prey from suitably positioned power poles and fence posts - seen during the day were Jackal Buzzards (6), Long-crested Eagles (5), Black-shouldered Kites (5), and a Forest Buzzard.

The weather was particularly in our favour; with rain the previous evening and a cold, cold night.  The day was chilly and stayed that way on a mostly cloudy day.  As a result, there were keen responses from almost all raptors except the BSK's, and resulted in seven birds caught during the day. Four JBs, and three LCEs.

smoky sunrise
the one that got away
first one for the day - photo credit Mark Brown
long-crested eagle - photo credit Lorinda Jordaan
not one but two. notice the difference in eye colour
the obligatory post release photos
simultaneous trapping is a first for me - photo credit Mark Brown
the largest bird louse I've ever seen, even relative to my big hands - photo credit Erin Wreford
stunning buzzards
I must, ashamedly and under duress, confess that I was the only person to bleed that day.  Having received a loving handshake (more accurately a finger-trap) from one tough Jackal Buzzard.  I suppose you will notice the teeny-tiny, skin-coloured band-aid – now that attention is drawn to it. 

spread wing to show the moult pattern - photo credit Mark Brown
seventh heaven, there goes the last one of the day - photo credit Erin Wreford


Darvill on Saturday was fantastic.  In the absence of the other SAFRING trainee's, and with a steady trickle of birds that never got overwhelming – there was an opportunity to complete a full four-hour stint of continuous ringing... Like a diligent nerd, Im going to subject you to a list of all the 43 birds (and 11 recaptures) from 21 (+2) species!

  (1)     Kurrichane Thrush                    
1       Spotted-backed Weaver          
1 (1) Red-faced Cisticola                   
2       Cape Wagtail                            
1 (1) Spectacled Weaver                  
4 (1) Levaillants Cisticola               
6 (1) Dark-capped Bulbul                
8 (2) Fan-tailed Widowbird            
1 (1) Yellow Warbler                         
1       Green-backed Cameroptera  
3       Black Saw-wing                        
1       Blue-billed Firefinch                
1 (1) Terrestrial Brownbul              
1        Cape White-eye (green)          
1       Olive Sunbird                            
  (1)   Lesser Swamp Warbler               
2        African Reed Warbler             
1       Rock Martin                               
1       Yellow-fronted Canary           
3        Lesser-masked Weaver           
2 (1) Red Bishop                                  
1        Brown-throated Martin          
1        Fan-tailed Cisticola                  

Wednesday, June 6, 2012

Research Update #2 – June camera trials

Click on a photo to start the slideshow of full sized images.

As you can see, the camera trap is quite something.  This has been a particularly exciting week and most of all because of the testing of an Ecotone BEV unit that I hope to use for the study.  This first unit needed to be evaluated before settling on a design.  With this trial a success, its now time to get another four of these cameras which will enable me to investigate the diet at five nests this year.

By using these cameras and photographing each item as it is eaten at the nest, this should be the most definitive method  for describing breeding diet (as opposed to bone collections, pellet analysis, or observations from a nearby hide).  Of course, we won’t be sure about what the adult male is eating on his hunting grounds or what they consume outside of their year of parenthood.  Luckily there is a long post-fledging period and as we have seen this year, juveniles that are two or three months out of the nest will still have their food delivered directly onto the nest, so this could well cover diet for most of the year.

With the support of Darryl, the landowner with the fortune of having this nest right above his house, this site in particular was chosen for the trial.  Because of Darryl’s interest, this pair has a well-known history.  The nest was first built in 1989! And since then one adult female, and one of the 9 juveniles produced were known to have been shot by anonymous locals.  Darryl keeps a keen eye on them, and in the last month this pair has been busily nest-building and occasionally copulating – promising signs for spring!

It was also a challenge to get back in the saddle, and on the rope.  Despite climbing many trees in Mauritius, the hurricane beaten forest there was a somewhat stunted canopy, and the highest pitch was at 27 meters.  Well the first climb for this project was probably 35 meters up.  It was a long slow grind to the top, forearm and thigh muscles burning!  Two hours later, having redirected the rope to an ideal fork for the maintenance climbs, and having positioned the camera three times over, while being somewhat distracted by an intimidating eagle glaring at me at eye level, I was back on terra firma.  Wonderful terra firma.

Four days later and I had to do it all again, time to switch out the small memory card for a 32 Gigabyte card.   A nice rope placement and a simple changeover with the unit meant that the climb was fast and efficient.  Having watched the eagles fly in with green pine branches that morning, and leaving together on their own accord, I was relieved that they were absent for the whole time I was roped in.  Getting to the ground and hastily downloading the data revealed 2,500 images in four days.  Many of these did indeed have an eagle or two in frame.  Initially one or both of the birds were irritated at this new box present at eye level.  This interest waned quickly, and we will know during the course of this extended trial how disruptive this effect might be. 

Best of all there was a stunning shot of the male with the pine branch.  I had just seen him fly in with the fresh nesting twig earlier that morning, and now I see him bent over placing the branch into the nest.

Yesterday morning Darryl sent me a text … 
 “the male just gave the female some prey, she is eating it on the nest - facing the camera.  I hope shes not too far back on the edge.”
This will be an impatient ten day wait until the extended trial is done and I can retrieve the data and see for myself!

Photo credits 7, 9, 10, 11 to Erin Wreford

Sunday, June 3, 2012

Word of the week = Euplectes

SAFRING training has been moving along at pace this month. 

An intimidating audience?

For a primary school educational day, Mark, Lindy and I set up an afternoon ringing station near Greendale Park in Howick.  It was very quiet at the nest, just a handful of birds caught, and soon enough the school bus turned up.  Mark made it a very exciting and engaging experience for them and the kids were putty in his hands… I even heard one girl of about twelve years say “when I grow up I want to be an or-neth-ollie-gist” - so cool!  A couple of boys were particularly interested in how hard the bite of each bird was.  I guess it was unfortunate that we didn’t catch a fiscal that day?  With a few birds left, I was suddenly delegated to the hot seat.  The pressure of a dozen children’s expectations was too much – and after ringing a couple of Euplectes, I pulled a wee Cisticola out of a bag.  Within seconds it had wriggled free of my clumsy sausage-fingers, and flittered past their noses.  They were all too happy to follow Marks direction, and give me an open-handed slap behind the ears.  

A few days later we were all up at 4:30 for another ringing session.  The old ringing site at Cedara Agricultural College had been active many years ago.  It had been neglected for a while, but more recently Karen Nelson has wanted to reinvigorate the action there.  Only problem is it is a sweet spot for Euplectes; flocks of bishops and quelea can fly through the reeds and in an instant there could be over a hundred birds in the net.  Many hands are needed.  Well it wasn’t quite that intense last Thursday morning, but we sure had a glut, and with the fogged morning threatening drizzle it was touch and go there for a while.

In any case, the day cleared up and many dozens of birds were ringed.  The ‘special’ of the day was Orange-bellied Waxbill.  I was stoked to have over an hour of good practice and get through thirty birds, mostly Red Bishops and Fan-tailed Widows.  With time came learning a technique with the pipsqueaks – ringing five Cisticolas and a Drakensberg Prinia without an escape. 

Lindy with a lot of work ahead.

This little dikkie ain't getting away this time.  Cisticola tinniens

Male Fan-tailed Widow.  Euplectes axillaris

Male Red-collared Widow. Euplectes ardens

Drakensberg Prinia. Prinia hypoxantha

It’s an on-going event… Up and coming this weekend is Darvill ringing again and potentially Sunday morning down the south coast.  On the south coast there are some great species around this Crowned Eagle site where I have been trying in vain to catch and ring a dastardly juvenile.  Recently we’ve seen on various trips; a pair of Little Sparrowhawks, Knysna and Purple-crested Turaco (they love taunting the eagle), White-eared Barbet, Crowned and Trumpeter Hornbills, Green Woodhoopoe …and many more besides.