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|All years||Observers: 1222||Cards: 87457||Records: 4624600||Incidentals: 355424||Pentads: 11767 (67.95%)|
|2013||Observers: 417||Cards: 5863||Records: 301440||Incidentals: 25056||Pentads: 2516 (14.53%)|
|WinterMAP||Observers: 180||Cards: 669||Records: 30464||Incidentals: 3224||Pentads: 510 (2.94%)|
In the Martial Eagle text for SABAP1 published in 1997, Andre Boshoff wrote: "Although numbers have decreased locally in many areas, often dramatically, the Martial Eagle is still widespread in southern Africa ... The conservation status provides cause for concern ... The main causes [of the decrease] are direct persecution (shooting and trapping) by small-stock farmers, indirect persecution by poisoning, drowning in sheer-walled reservoirs, reduction of natural prey through habitat alteration and degradation, and electrocution on electricity pylons." The process seems to have been ongoing between SABAP1 and SABAP2. The dominant colour on this range change map for Martial Eagle is RED, which indicates quarter degree grid cells where the species was recorded in SABAP1 but not in SABAP2.
The general wisdom two decades ago was that birds of prey such as the Martial Eagle were doing OK in the large conservation areas such as the Kruger National Park. In fact, in the 2000 Red Data Book, Keith Barnes expressed the hope that the large conservation areas could "act as source areas for recolonization" once "landowners' attitudes" towards this species had become more tolerant. But closer inspection suggests that Martial Eagles are not doing well even in these areas. For example, the lower map shows the northeastern corner of South Africa, including the Kruger National Park. The two numbers in each quarter degree grid cell are the SABAP1 and SABAP2 reporting rates, at the top and bottom, respectively. Most of these quarter degree grid cells have quite large samples of checklists, for both projects. So the reporting rates are likely to be fairly well estimated. The most frequently occurring colour is ORANGE, indicating a decrease in reporting rates. In general, many of the changes are so large that they cannot be attributed to differences in protocol between the two projects. The largest changes are from SABAP1 reporting rates of 96.8% to 0% in SABAP2, and from 82.4% to 5.3%.
The decreases in the Kruger National Park cannot easily be attributed to any of the human-related factors in the list of causes mentioned above. So it is tempting to suggest that environmental factors are also impacting on Martial Eagles. It could be disruptions to the prey base, it could be climate change related. But it certainly needs investigation.