Double jeopardy for ecologically rare birds and terrestrial mammals

endangered species
Credit: Pixabay/CC0 Public Domain

Common assumptions notwithstanding, rare species can play unique and essential ecological roles. After studying two databases that together cover all known terrestrial mammals and birds worldwide, scientists from the CNRS, the Foundation for Biodiversity Research (FRB), Université Grenoble Alpes, and the University of Montpellier have demonstrated that, though these species are found on all continents, they are more threatened by human pressures than ecologically common species and will also be more impacted by future climate change. Thus, they are in double jeopardy. The researchers’ findings, published in Nature Communications (October 8, 2020), show that conservation programs must account for the ecological rarity of species.


It has long been thought that rare species contribute little to the functioning of ecosystems. Yet recent studies have discredited that idea: Rarity is a matter not only of the abundance or geographical range of a species, but also of the distinctiveness

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Double jeopardy for ecologically rare birds and terrestrial mammals — ScienceDaily

Common assumptions notwithstanding, rare species can play unique and essential ecological roles. After studying two databases that together cover all known terrestrial mammals and birds worldwide, scientists from the CNRS, the Foundation for Biodiversity Research (FRB), Université Grenoble Alpes, and the University of Montpellier[1] have demonstrated that, though these species are found on all continents, they are more threatened by human pressures than ecologically common species and will also be more impacted by future climate change. Thus they are in double jeopardy. The researchers’ findings, published in Nature Communications (October 8, 2020), show that conservation programmes must account for the ecological rarity of species.

It has long been thought that rare species contribute little to the functioning of ecosystems. Yet recent studies have discredited that idea: rarity is a matter not only of the abundance or geographical range of a species, but also of the distinctiveness of its ecological functions.

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Cheating birds mimic host nestlings to deceive foster parents — ScienceDaily

The common cuckoo is known for its deceitful nesting behaviour — by laying eggs in the nests of other bird species, it fools host parents into rearing cuckoo chicks alongside their own. While common cuckoos mimic their host’s eggs, new research has revealed that a group of parasitic finch species in Africa have evolved to mimic their host’s chicks — and with astonishing accuracy. The study is published in the journal Evolution.

Working in the savannahs of Zambia, a team of international researchers collected images, sounds and videos over four years to reveal a striking and highly specialised form of mimicry. They focused on a group of finches occurring across much of Africa called the indigobirds and whydahs, of the genus Vidua.

Like cuckoos, the 19 different species within this group of finches forego their parental duties and instead lay their eggs in the nests of other birds. Each

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Bright light bars big-eyed birds from human-altered landscapes

Bright light bars big-eyed birds from human-altered landscapes
In a study of 240 bird species, Florida Museum of Natural History researchers found strong links between eye size, light and habitat use. The findings suggest eye size could be an important predictor for how sensitive certain bird species may be to habitat disturbance. Credit: Ian Ausprey/Florida Museum

New research shows the glaring light in human-altered landscapes, such as livestock pastures and crop fields, can act as a barrier to big-eyed birds, potentially contributing to their decline.


Florida Museum of Natural History researchers found strong links between bird eye size, habitat and foraging technique. Birds that kept to the shade of the forest had larger eyes than those that inhabited the canopy, and birds with relatively small eyes were more numerous in agricultural settings.

The findings suggest eye size is an overlooked, but important trait in determining birds’ vulnerability to changes in their habitat and could help inform future research

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San Francisco birds sing differently in the pandemic

San Francisco birds started singing differently in the quiet of the coronavirus lockdown, says a study in Science.



a small bird perched on a branch: The Covid-19 shutdown created a "proverbial silent spring" across the San Francisco Bay Area, prompting the white-crowned sparrow to sing differently.


© Double Brow Imagery/Shutterstock
The Covid-19 shutdown created a “proverbial silent spring” across the San Francisco Bay Area, prompting the white-crowned sparrow to sing differently.

Before, urban white-crowned sparrow’s breeding territories were almost three times as loud as rural territories, the study found.

But during the pandemic, researchers noted that noise levels in urban areas were drastically lower. In fact, they were consistent with traffic flow in the mid-1950s.

“In other words, the Covid-19 shutdown created a proverbial silent spring across the SF Bay Area,” researchers noted.

By analyzing traffic flow data from the Golden Gate Bridge, researchers found that vehicle crossings from April to May 2020 returned to levels not seen since 1954. While noise recordings are not available from the 1950s, researchers said this indicates that a brief

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