|
Ground-nesting birds known as lapwings, according to new research, use the design of their nests and surroundings to hide from predators.
Changes in land management and high predator populations, such as foxes and crows, are causing many ground-nesting species to decline. If too many eggs and chicks are ingested, conservation efforts may fail. The current study, led by the University of Exeter, evaluated the visibility of lapwing nests in terms of cover (also known as "occlusion") and camouflage using models that imitate variouspredators' vision and viewing angles. The findings demonstrated that, despite nesting in open fields,lapwingscan hide their eggs by leveraging tiny differences in the landscape, rendering them undetectable to groundpredatorssuch asfoxesfrom more than 1.5 metres away. Like children playing hide and seek, lapwings use cover to complement their camouflage, said lead author George Hancock, from the Centre for Ecology and Conservation on Exeters Penryn Campus in Cornwall. If a nest is properly concealed in this way, it doesnt matter how good a predators vision is they simply wont be able to see it until they are nearly on top of it. Nests and eggs are also camouflaged blending in with their surroundings by matching the colour and pattern of their background but it appears this is a secondary defence. Hancock worked with the Game and Wildlife Conservation Trust (GWCT) to estimate the form and height of lapwing nests and their surroundings using smartphone 3D scanners. He also utilised specialised cameras to assess camouflage from the perspective of the lapwing's predators, who can see UV light (foxes, crows, and raptors). Lapwings tended to choose uneven ground for their nests, Hancock said. They selected slightly elevated positions, reducing the risk of flooding and allowing them to see predators without being so high as to stand out to predators. Lapwing populations have more than halved since the 1970s. The findings could help inform conservation efforts for this declining species, which is an iconic part of farmland in the UK and beyond. Habitat variation appears to be crucial for allowinglapwingschoice in where to nest, Hancock explained. The growth of intensive agriculture has left ground-nesting birds with poorer choices of where to nest. Grazed fields provide goodhabitat, as long as theyre not overstocked with too manygrazing animals. New technology is allowing us to better measure how animals see and view the world." Tilled fields can provide really good camouflage for eggs which match the bare earth and can be concealed by the rough geometry, but might be problematic forchickswhich are more exposed. (ANI)
|
