1 March 2010
Issue # 7
Dear hadeda enthusiasts,
This being our first newsletter of 2010, it may be a little late (actually very late...) to mention, but we hope you had a fantastic New Year’s and festive season! We hope that 2010 is a great year for you, and that already this far into the year things are going well. 2010 started off quite busily for the hadeda team – and we do have a good reason for sending out our first newsletter so late; Greg Duckworth, who is working for his MSc under the supervision of Res Altwegg, spent the whole of January and February completing the population analyses for hadedas. These results will go into his first chapter of his thesis, and it’s fantastic to have results from all the hard work. This analysis makes use of all our ringed birds, all the resightings of ringed birds, and all the nesting information we have had over the past three years. So thank you to everyone who submitted any information to us – without your valuable contributions we could never have produced these sets of results.
| Flocks of foraging hadedas are such a common site in the suburbs. Their ability to successfully colonise urban landscapes has allowed them to become one of the most abundant, well known species in South Africa (and loud!), especially in the Western Cape.
Photo: Jessie Blackshaw
Photo: Greg Duckworth
| As hadedas have colonised the suburbs and become more numerous, interactions with people were inevitable. Often, when a nestling falls from a nest, its parents will feed it on the ground. On the rare occasion where they abandon it, people volunteer to take care of it until its ready to fly. Alongside is a picture of hadeda VN, who fell from a nest near Panorama, and was cared for by volunteers near his nest. VN is standing on the side of a wooden box, lined with newspaper, with a bunch of twigs in the centre made to resemble a nest! I'm glad to report that VN is flying around now like any other normal hadeda, all thanks to his surrogate parents who took very good care of him.
As far as results go: only just under two out of 10 juvenile hadedas survive their first year! Although this number may initially seem quite low, compared to first year survival of other birds it’s actually quite high. The first year of life is a tough time for many birds, and it is common that only 1 out of 10 survive it, so the hadedas seem to be doing comparatively well. Once hadedas make it to their first birthday, their chance of surviving from 2nd to 3rd year is much higher; 8 out of 10 make it through that time period. We expect second year survival to be much higher than first, so it’s great that the results are fitting with our expectations. However, our confidence in our 2nd year survival estimate is still low. Since we only ringed nestlings and so many of them disappear, there is not a lot of data on birds older than one year yet, which makes estimating their survival a bit more difficult. We were also unable to estimate 3rd year survival, as we had too few data. This is where you guys can again contribute to our project, and become a citizen scientist; by reporting any ringed birds! Any data is valuable data, and we really do appreciate every input. Nonetheless, from the data we do have, and applying some assumptions, it looks like the hadeda population in Cape Town is increasing by just under 5% per year. Thus, it would effectively double in just under 14.5 years, which is incredibly fast!
It’s been a bit slow on the fieldwork side recently with only a few nests here and there, but that’s expected as we’re out of the breeding season. Notably, we ringed our 200th bird in October last year! This was a terrific achievement for our project, as we've only been in operation for just over three years. If you have ever seen us ring chicks you will know just what an effort it is to ring a single brood, so 200 ringed birds is fantastic. Our 200th bird has the combination VF – “Very Fortunate” – so keep your eyes open for him! We are now on 218 ringed birds, so you stand a very good chance of seeing any ringed birds in a flock.
| Hadeda VF - The 200th bird that the hadeda project ringed! VF and his sibling VJ were constantly harassed by hawks and crows during their development stages, and for them to make it all the way until fledging is fantastic. VF and VJ are often seen around Bergvliet and Constantia, so keep your eyes open for them.
Photo: Charmien de la Mare
Photo: Guy Midgley
| FX foraging in a Garden in Tamboerskloof. FX was ringed in Camps Bay in October 2007, and was seen around his nest until mid 2008. Thereafter he wasn't seen until the end of December 2009, when this photo was taken, where he was just under 2.5 years old. We don't know what happened to him in the meantime, but it's likely that he was in and around the core area but just wasn't resighted. These kinds of resightings are incredibly valuable to us, so please continue to keep your eyes open for any ringed birds. Who knows -- it just might be one the first birds we ringed over three years ago!
So that is an update with what’s happening in our project. A sincere thank you to all who have contributed to the project in anyway, making it possible to produce the population analysis. Hopefully it won’t be too long until you next hear from us. As usual, please keep on reporting any active nests, resights, interesting observations or photos about hadedas.
Greg Duckworth (Tel. 021 799 8861) Res Altwegg (Tel. 021 799 8809) and Doug Harebottle (Tel. 021 650 2330)