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Army ant invasion of leatherback nests in Gabon

Egg mortality is one of the main factors affecting life history and conservation of oviparous species. A massive and cryptic colonisation of many leatherback turtle (Dermochelys coriacea) eggs is presented in the most important rookery for the species in Gabon. A total of 163 nests were exhumed at Kingere beach, revealing that only 16.7% of eggs produced hatchlings. In the 59% of the nests, more than half of the eggs were dead and attacked by invertebrates and 94% had at least one egg affected by invertebrates. The rate of eggs and SAGs (yolkless eggs) affected by invertebrates within a clutch ranged from 0% to 100%, with an average proportion of 39% and 52%, respectively. The most common invertebrates interacting with the eggs were ghost crabs and insects that affected 51% and 82% of the nests, respectively. Crab and insect co-occurred in 33% of the affected nests. Ants, identified as Dorylus spininodis (Emery 1901) were found in 56% of the excavated nests. However, it was not possible to determine if the ants predated alive eggs or scavenged dead eggs. Very often, hundreds of ants were found drowned within dead eggs. Termites and other invertebrates were associated with the clutch environment and identified as opportunistic feeders, being this is the first record of interaction between termites and sea turtle eggs. An unusual ecological interaction within the leatherback clutches between termites and ants was found in 11% of the nests. The abrupt transition between the soil forest and the beach might be favouring a thriving microbial and invertebrate activity in the sand profile that colonises the nests. informacion[at]ebd.csic.es: Ikaran et al (2020) Cryptic massive nest colonisation by ants and termites in the world's largest leatherback turtle rookery Ethol Ecol Evol 2020. Doi 10.1080/03949370.2020.1715487


https://www.tandfonline.com/doi/abs/10.1080/03949370.2020.1715487
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Red mud as makeup in the Egyptian vultures

Red mud as makeup in the Egyptian vultures

It is well-established that plumage colours are important for avian visual communication and are used to signal social information. Yet, little is known about the ability of birds to modify the expression of plumage colours with exogenous materials after feather development, a phenomenon also known as avian cosmetics. The deliberate staining of feathers with red soil in a social signalling context has so far only been described in the Bearded vulture. Here, for the first time feather painting behaviour is described in the Egyptian vulture, another Old-World scavenger. Egyptian vultures are considered endangered worldwide, but 60 breeding pairs and a total population of about 300 individuals still occur on Fuerteventura (Canary Islands, Spain). Two bowls were presented to the birds visiting the main feeding station: one with red soil dissolved in water and one containing only water. A remarkable response was observed with 18 different birds painting themselves with red soil to different degrees and only one bird took a bath in the bowl containing water only. These observations of multiple birds taking mud baths in the wild are the first ever filmed. The exact function of this behaviour is not yet clear, as no evidence was found for a status signalling function as has been suggested for the behaviour in the Bearded vulture. However, little is still known about Egyptian vulture group dynamics and patterns of social relationship within their society and it is possible that the behaviour serves a different social function in this species. This work adds a new and unusual behaviour to the already impressive behavioural repertoire of Egyptian vultures and opens exciting new opportunities to test alternative hypotheses for the evolution of avian cosmetics or non-vocal communication in birds in general. informacion[at]ebd.csic.es: van Overveld et al (2017) Cosmetic coloration in Egyptian vultures: Mud bathing as a tool for social communication? Ecology doi:10.1002/ecy.1840


http://onlinelibrary.wiley.com/doi/10.1002/ecy.1840/full