Tuesday, 2 June 2015

Publication: Bird densities and capture rates from a Mediterranean-type ecosystem

2013 was a year of hard field work. A bit like every year before I guess. But the work of that year was part inspired by the late Phil Hockey. Phil was my supervisor for the first year of my post-doc in 2012, and passed away in January of 2013. Phil was one of South Africa's leading ornithologists, a charismatic and hard working individual much respected in his field.

I have to admit I didn't like Phil at first: he shot down my first post-doc proposal in a hail of bullets. But he only did this to maintain standards at the Percy FitzPatrick Institute: and admittedly I was not up to standard. In fact, I probably made it in because Phoebe Barnard dragged me in by the ear. However, I'm an obstinate fool and I knew what I wanted to do and that it could be done, so I stuck it out. Perhaps it was his quest for Excellence that has shaped what I have achieved so far to date.

One thing that bothered Phil was that during density estimate surveys I would not be detecting all the birds that were in the area and available to be counted. A valid concern, and one that is these days addressed by a variety of statistical techniques. However, since part of my research project was to monitor Cape Sugarbirds in an attempt to see if and how they disperse, he thought that a combined count/ringing technique would help us identify birds that were escaping the counts. So, in 2013 that was what I did: counted birds in formal surveys, informally at the nets, and captured birds on a wide scale.

While a focus of the research was to find out if there were a set of birds that were escaping detection, we did not find this. Instead, changes in bird capture rates at nets were better explained by other things: like placement in relation to resources; and bird size.

However, one useful aspect of the work for me was that I could confirm that there was a relationship between densities and ringing capture rates. This means that all alone here in the wilderness I don't have to count and catch birds: I can concentrate in the meantime on just catching them, as I should be able to track back changes to density for the more common species.

Of course Phil never got to read this publication, but you have the opportunity to do so via:


Orange-breasted Sunbird: High capture rates; High densities

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