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Recent distribution and population trends for Secretarybirds Sagittarius serpentarius in South Africa, Lesotho, and Eswatini from citizen science data

Published online by Cambridge University Press:  18 September 2024

Christiaan Willem Brink Open the ORCID record for Christiaan Willem Brink [Opens in a new window] ,
Alan Tristram Kenneth Lee Open the ORCID record for Alan Tristram Kenneth Lee [Opens in a new window] ,
Dinusha Priyadarshani Open the ORCID record for Dinusha Priyadarshani [Opens in a new window] ,
Wen-Han Hwang Open the ORCID record for Wen-Han Hwang [Opens in a new window] ,
Ernst Retief ,
Kishaylin Chetty Open the ORCID record for Kishaylin Chetty [Opens in a new window]  and
Melissa Andrea Whitecross Open the ORCID record for Melissa Andrea Whitecross [Opens in a new window]
Christiaan Willem Brink*
Affiliation:
BirdLife South Africa, Isdell House, Dunkeld West 2196, South Africa FitzPatrick Institute of African Ornithology, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa
Alan Tristram Kenneth Lee
Affiliation:
BirdLife South Africa, Isdell House, Dunkeld West 2196, South Africa FitzPatrick Institute of African Ornithology, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, South Africa
Dinusha Priyadarshani
Affiliation:
Institute of Statistics, National Chung Hsing University, Taichung, Taiwan
Wen-Han Hwang
Affiliation:
Institute of Statistics, National Tsing Hua University, Hsinchu, Taiwan
Ernst Retief
Affiliation:
BirdLife South Africa, Isdell House, Dunkeld West 2196, South Africa
Kishaylin Chetty
Affiliation:
Biodiversity Centre of Excellence, Eskom Holdings SOC Ltd, Megawatt Park, Sunninghill 2157, South Africa
Melissa Andrea Whitecross
Affiliation:
BirdLife South Africa, Isdell House, Dunkeld West 2196, South Africa School of Animal Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, Braamfontein 2050, South Africa
*
Corresponding author: Christiaan Willem Brink; Email: christiaanwillembrink@gmail.com
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Summary

The Secretarybird Sagittarius serpentarius is a charismatic raptor of the grasslands and open savannas of Africa. Evidence of widespread declines across the continent has led to the assessment that the species is at risk of becoming extinct. Southern Africa was identified as a remaining stronghold for the species, but the status of this population requires reassessment. To determine the status of the species in South Africa, Lesotho, and Eswatini, we analysed data from a citizen science project, the Southern African Bird Atlas Project (SABAP). We implemented novel time-to-detection modelling, as well as summarisation of changes in reporting rates, using standard metrics, to determine the trajectory of the population. To cross-validate our findings, we used data from another citizen science project, the Coordinated Avifaunal Roadcounts (CAR) project. While our results were in agreement with previous studies that have reported significant declines when comparing SABAP1 (1987–1992) and SABAP2 (2007 and onwards), all analysis pathways that examined data within the SABAP2 period only, as well as CAR data from this period, failed to show an alarming declining trend over this more recent time period. We did, however, find some evidence for decreases in Secretarybird abundance in urban grid cells. We used random forest models to predict probability of occurrence, as well as probability of abundance (reporting rates) for the assessed region and provided population estimates based on these analysis pathways. Continued monitoring and conservation efforts are required to guard this population stronghold.

Keywords

Citizen scienceConservationPopulation declineSecretarybirdThreatened species
Type
Research Article
Information
Bird Conservation International , Volume 34 , 2024 , e23
Copyright
© The Author(s), 2024. Published by Cambridge University Press on behalf of BirdLife International

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