Friday, 27 February 2015

Van Stadens revisited

So far I have enjoyed every trip undertaken to the ever-in-bloom van Stadens Wildflower Nature Reserve, just outside Port Elizabeth. All the trips have been bird ringing trips, of which I've blogged about one visit before, and on each visit I've handled a new species of bird.

The last two nights I camped at Falcon Rock with Ruby and Dan (UK volunteers) and we headed to the reserve on two mornings to meet up with Ben and Jerry. Jerry is Ben's Master's student looking at differences in foraging strategy between male and female Cape Sugarbirds, to try and understand why females appear to be more stressed (they weigh less) in hot years.

Tuesday morning was cold and wet, but as it was overcast, we had a good haul for the morning, with over 50 birds dominated by sunbirds and sugarbirds. My new birds for the day were Yellow-eyed Canary and Green-spotted Wood-dove. We were assisted by Nick, another of Ben's students who will be starting a Master's on Rufous-eared Warbler (not found at Van Stadens but a bird of arid Karoo), and he was put to good use extracting birds from the widely dispersed nets.

Dan seeks shelter from the drizzle while Ruby and Jerry ring birds

Checking for wing molt and beautiful colours on this Emerald Spotted Wood-dove

Synchronized cataplexy tests (tonic immobility)

In their hands: A young Greater Double-collared Sunbird male doing tonic time before its release

Amethyst Sunbird males are gorgeous

as are King Proteas

Young Lesser Honey Guide

Wednesday dawned not much better, we'd been listening to rain from our tents all night, but it cleared enough to put up some nets. It was gratifying to get several recaptured Cape Sugarbirds during the morning – nice to know they are still around, and it gives a chance for Jerry to show he is getting independent samples for his research.

On each visit it has also been impressive to see the fruits of the labours of the Friend's of Van Stadens. This time recent work was very obvious: the large gum trees in the middle of the reserve had been felled. While raptorphiles might get uppity about this, I approve as exotic trees are the biggest current threat to Fynbos integrity. On a tangent, I don't believe that cutting down the large exotic trees that raptors like to nest in will impact raptor populations as the raptos are simply choosing the largest trees to nest, which happen to be exotics, but would then nest in the next best thing, albeit smaller stunted endemic tree species. I don't believe there is evidence they would simply not nest.

Also – I was very excited to see the first signs of a bird hide being built passing through the arboretum. Two thumbs up to Mr and Ms Goossens for their efforts! I for one can't wait to use the final product. If their energy and enthusiasm for the environment was virulently contagious we'd be living on a more beautiful and healthier planet.

Sunday, 15 February 2015

Fynbos Birds: Conservation Status and impacts of Climate Change

A summary paper focusing on our six main endemic birds of the Fynbos came out in the journal Bird Conservation International earlier this year. I calculated bird densities, population sizes, identified preferred fire successional preference and examined ranges from SABAP2 data. I also used the atlas data to identify trends for the Fynbos birds and a suite of other endemic birds (simply reporting rate changes and range changes).

A bit of a concern is that the group of Fynbos endemic birds is generally the worst off, with Cape Rockjumper and Protea Seedeater fairing particularly badly comparing between atlas projects. While the degree of population change that this really represents is still an item of discussion, it was worthy to note that these changes were well explained by the species tolerance (or intolerance) to warm temperatures as calculated from a physiology project conducted in 2013 by Robyn Milne. In fact, in the absence of any other explanatory variables, climate change (particularly warming) seems to be the best reason for these changes at this time. After all, Mountain Fynbos is little modified by the usual host of problems associated with human land conversion. For Cape Rockjumper in particular, which stresses out at just over 30 degrees (the lowest of 12 species tested), it appears from various angles that range is limited by temperature. With an increase of between 0.5 and 1 degree, this translates to a vertical loss of space of around 100 meters, which isn't a good thing if you're already a species that prefers mountain tops – there is no where left to go, and a temperature increase of 4 degrees will mean there will no more comfortable living space left for this species.

How exactly hotter temperatures may influence behaviour and breeding is now the focus of the research of the Hot Fynbos Birds project team. Krista Oswald is just starting a Masters project on the topic and we're hoping for some good news from this in the next year or two.

The official paper can be downloaded from the publisher website here
and a copy is available here

The kudos perspectives link:


Too hot for his own good: A male Cape Rockjumper
Krista Oswald and Kate Beer monitoring Cape Rockjumpers. No easy task!

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