The moth Achaea catocaloides Guenee (Lepidoptera: Erebidae, formerly Noctuidae) experiences periodic population irruptions in tropical Africa. Large numbers of adult moths were observed in the Kakamega Forest, Western Kenya in March 2012. Estimated densities of adult moths flying in surveyed forest areas were 6.8 individuals per square metre. Roosting moth density was estimated at 12.7 individuals per 50 cm long branch on two common forest tree species: Croton megalocarpus and Bridelia micrantha. Based on scaled-up data from transect counts we conservatively estimate that this irruption contained 800 million -1.5 billion moths. The Achaea moths were common throughout the indigenous forest and were being preyed on by birds and monkeys. These population irruptions occur periodically in African forests, but the underlying causes and factors driving them remain undetermined. DNA barcodes of Achaea catocaloides, Achaea catella and Achaea lienardi are provided to facilitate identification of future irruption events.
Summary
The ‘Endangered’ Cape Vulture Gyps coprotheres has been monitored across its range for decades through disparate studies varying in geographical scope and length. Yet, no long-term, range-wide survey exists for the species. Coordinated monitoring across the range of the Cape Vulture would be logistically challenging but provide a holistic view of population dynamics in this long-lived species that forages across much of southern Africa. Here, we report breeding pair counts from seven colonies in the Cape Vulture’s north-eastern breeding region from 2010 to 2019. We used state-space models to assess population growth across time. Manutsa, Soutpansberg, and Nooitgedacht colonies increased significantly over the study period, with three other colonies having positive estimates of population growth, but 95% credible intervals overlapped zero. The smallest colony at Moletjie is declining toward extirpation; only one breeding pair remained in 2019. Our results suggest the north-eastern population has been stable or increasing since 2010 with our 2019 surveys counting 2,241 breeding pairs across all sites. Indeed, there is an 89% chance that the population across the colonies we monitored increased from 2010 to 2019. Coordinated, range-wide, full-cycle monitoring is needed to thoroughly assess conservation status and efficacy of conservation actions taken for this endangered species.
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