animal demography unit monitoring the mystery ecretarybirds – one of ’s we can be that any changes in reporting rates most iconic and enigmatic raptor are real and reflect actual changes in the species – appear to be in decline across population. The colours in the graph give an Smuch of the country. Most alarmingly, it indication of how sure we are: the darker they seems that the most serious decline is occur- are, the greater certainty there is. ring in the , supposedly The data from the CAR project indicate one of the last havens for large raptors in that, other than in the , the South Africa. This is one of the key results in overwhelming majority of Secretarybirds oc- a paper published in May 2014 in the open- cur in natural habitats. In the wheat-growing access journal PLoS ONE. districts of the Western Cape (the Overberg The paper, titled ‘Secretarybird Sagittarius and the Swartland), at least half the Secre- serpentarius population trends and ecology: tarybirds were in agricultural lands. The insights from South African citizen science Secretarybird’s habitat of choice is open, data’, uses data from the Coordinated Avi- grassy areas, and it is likely that the birds have faunal Roadcounts (CAR) project and the two adapted to the farmland in the Western Cape secretarybird albert froneman projects to assess the current status because it more closely resembles their pre- of Secretarybirds in the country. Changes in ferred habitat than the surrounding . Another important outcome of this reporting rates from SABAP1 to SABAP2 give Despite this, the analyses showed that they research is significant: these findings would us a good idea of how the population may still favoured natural habitats; it’s just that so not have been possible without the data have changed between 1990 and 2012, and little of those environments remains. contributed by citizen scientists. The fact data from the CAR project can tell us about One likely cause of the overall decline of the that this paper was published in PLoS ONE the habitats the species is using. Secretarybird throughout its range is the loss demonstrates, once again, that citizen science Of the 39 quarter degree grid cells in the of its usual habitats as a result of land trans- data withstand the highest levels of scrutiny Kruger Park, there were decreased reporting formation. This, however, cannot be the case and can become a key input for high-quality rates for Secretarybirds in 37, i.e. 95 per cent. in the Kruger National Park, and in this and research. In 31 of these, the decreases are so significant other areas, widespread bush encroachment This paper is based on results from Sally that a statistician would sit up and take is probably an important threat to Secretary­ Hofmeyr’s PhD in the ADU and her post- notice. These changes are indicated by the red birds. Other potential causes for decreases doctoral fellowship at the University of the and orange sections of the bars in the graph. include powerline and fence collisions, Witwatersrand. In the graph, there is a line for each province occasional inadvertent poisoning by insecti- SALLY HOFMEYR & LES UNDERHILL of South Africa, and one for the Kruger Park. cides, and human disturbance. The red, orange and yellow sections of Reference: Hofmeyr, S.D., Symes, C.T., Underhill, each line indicate declines, while the L.G. (2014) ‘Secretarybird Sagittarius serpentarius Limpopo light green, dark green and blue sec- population trends and ecology: Insights from KZN South African citizen science data.’ PLoS ONE 9(5): tions indicate increases. Mpum. We all recognise that there is gener- Gauteng e96772. doi:10.1371/journal.pone.0096772 ally an element of chance in whether N West we see a bird species on a given day, W Cape The six colours represent the percentages even in an area where we know it F State of grid cells falling into a graded series of occurs. This is why we need deep cover- E Cape categories, from red, representing severe N Cape age of grid cells in the atlas projects decreases, to blue, for big increases. It is (i.e. as many checklists as possible for KNP evident that there has been a serious decline each grid cell) – the more checklists we in Secretarybird reporting rates between the 0% 20% 40% 60% 80% 100% get for each area, the more confident first and second bird atlas projects.

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