Lapwings are masters of camouflage, hiding in plain sight

New research from the University of Exeter reveals that lapwings, ground-nesting birds, have evolved unique methods to remain hidden from their predators.

Clever strategies

Amidst the vast expanse of open fields, one might wonder how ground-nesting birds protect their nests from predators. The answer, according to recent research, lies in the birds’ innovative use of terrain and surroundings. 

Lapwings, in particular, have demonstrated an impressive knack for using these natural features to hide in plain sight.

Decline of ground-nesting birds

Ground-nesting species across the world are in a state of decline, and various factors have driven this decline. Land management changes, such as intensive farming and urban development, have considerably impacted their habitats. 

A surge in the populations of predators like foxes and crows exacerbates the problem. These predators are a significant threat to the eggs and chicks, leading to reduced bird populations and the failure of conservation projects aimed at preserving these species.

Lapwing nesting habits

The Exeter team set out to investigate the nesting habits of lapwings to better understand their survival tactics. The study primarily focused on the visibility or “occlusion” of lapwing nests. 

Using advanced models that emulate the vision and viewing angles of predators, the experts assessed the effectiveness of lapwing camouflage techniques.

What the researchers discovered 

The findings are fascinating. Even in open fields, lapwings have mastered the art of hiding their eggs by exploiting small variations in the terrain. 

Such variations make the eggs practically invisible to ground-based predators like foxes if they are further than approximately 1.5 meters away.

“Like children playing hide and seek, lapwings use cover to complement their camouflage,” said study lead author George Hancock, from the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“If a nest is properly concealed in this way, it doesn’t matter how good a predator’s vision is – they simply won’t 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 their backgrounds colour and pattern – but it appears this is a secondary defense.”

How the research was conducted 

Hancock collaborated with the Game and Wildlife Conservation Trust (GWCT) and used smart phone 3D scanners to measure the shape and height of lapwing nests and their surroundings.

Specialized cameras were used to measure camouflage from the perspective of the lapwing’s predators (foxes, crows and raptors), which can see ultraviolet light.

“Lapwings tended to choose uneven ground for their nests,” said Hancock. “They selected slightly elevated positions, reducing risk of flooding and allowing them to see predators – without being so high as to stand out to predators.”

Conservation efforts

Lapwing populations have more than halved since the 1970s. This research provides crucial insights for their conservation. 

Understanding the natural defense mechanisms of these birds can aid in designing better and more effective conservation strategies.

For instance, ensuring that natural terrains with variations are preserved or even created could enhance the safety of these nests. 

Furthermore, this knowledge can be applied to other ground-nesting species, potentially reversing the decline seen in their numbers.

Study implications 

“Habitat variation appears to be crucial for allowing lapwings choice 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 good habitat, as long as they’re not overstocked with too many grazing 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 for chicks which are more exposed.”

By providing habitats that compliment lapwing camouflage, Hancock said conservation managers could use “nature’s toolkit” – in addition to direct predator control – to help lapwings breed successfully.

The study was funded by the Natural Environment Research Council and GWCT. The findings are published in the journal Ecology and Evolution.

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