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Human footprint and vulture mortality

Events of non-natural mortality in human-dominated landscapes are especially challenging for populations of large vertebrates with K strategies. Among birds, vultures are one of the most threatened groups experiencing sharp population declines due to non-natural mortality. Factors causing non-natural mortality are usually studied separately. However, the potential use of an integrated index able to predict large-scale mortality risks of avian scavengers could be especially useful for planning conservation strategies. Here, the Human Footprint index was used to examine the impact of landscape anthropization on the survival rates of 66 GPS-tagged adult Eurasian griffon vultures (Gyps fulvus) in two Spanish regions. Foraging in more anthropized areas resulted in a significantly higher individual mortality risk mainly due to collisions with vehicles, poisonings, electrocutions and fatalities with wind turbines. Mean yearly survival rates were estimated at 0.817 and 0.968 for individuals from the more and less anthropized regions, respectively. Additional research should investigate whether some vulture populations could be acting as sinks unnoticed due to metapopulation dynamics. From a broader point of view, this study shows that a straightforward Human Footprint was a useful index to predict the survival of top scavengers and can be highly applicable to planning large-scale conservation measures. informacion[at] Arrondo et al (2020) Landscape anthropization shapes the survival of a top avian scavenger. Biodivers Conserv.
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“Planned obsolescence” in the plumage of larks

"Planned obsolescence" in the plumage of larks

Larks (Alaudidae) present a heavily worn plumage for the most part of the annual cycle, to the point that identification field guides typically depict lark species in both fresh and worn plumages. The ephemeral nature of lark feathers is even more strange knowing that larks are among the few passerines undergoing a single annual molt. Contrarily, a majority of songbirds moult feathers twice a year. Larks are dull-colored ground-dwelling birds living in open areas, thus occupying a niche where abrasion by air and soil particles is maximal. Authors observed that lark feathers have unmelanized fringes and are prone to breakage. Larks may have turned need into a virtue: they possibly cannot avoid a premature damage of their fragile plumage, and instead of incurring the cost of molting repeatedly, they gain the advantage of a form of crypsis known as disruptive camouflage. When feathers break, they create a serrated random pattern, cancelling out the effect of smooth lines more easily detected by predators. informacion[at] Negro et al (2019) Adaptive plumage wear for increased crypsis in the plumage of Palearctic larks (Alaudidae). Ecology