How camouflaged birds decide where to blend in

July 31, 2017

Animals that rely on camouflage can choose the best places to conceal themselves based on their individual appearance, new research shows.

The camouflage and concealment strategies of various animal species have been widely studied, but scientists from Exeter and Cambridge universities have discovered that individual wild birds adjust their choices of where to nest based on their specific patterns and colours.

The study looked at nine remarkably hard-to-see ground-nesting bird species (nightjars, plovers and coursers).

"Each individual bird looks a little bit different, and we have shown that they can act individually," said project co-leader Professor Martin Stevens, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"This is not a species-level choice.

"Individual birds consistently sit in places that enhance their own unique markings, both within a habitat, and at a fine scale with regards to specific background sites."

The study, carried out in Zambia, showed that individual birds chose backgrounds that enhanced their camouflage to the visual systems of their main predators - being better matched to their chosen backgrounds than to other places nearby.

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Camouflage influences life-and-death decisions that animals make

Date: June 9, 2016

Source: University of Exeter

Nesting birds time their escape from an approaching predator depending on how well camouflaged their eggs and their own bodies are, researchers from the University of Exeter and the University of Cambridge have discovered.

This is the first study to show that the camouflage of an animal or that of its offspring can explain the variation in risk-taking behaviour when approached by a predator.

Researchers worked with a team of skilled local assistants in Zambia to find the nests of several species of ground-nesting birds. Once a nest was found they monitored its progress, recording the escape distance of the adult bird each time they approached and, using camera traps, identified key predators such as banded mongooses, vervet monkeys and grey-headed bush shrikes -- and even human children.

In complex environments it is hard for animals to perfectly match their background. When an animal's camouflage is poor it has a higher risk of being detected and eaten by a predator, so it should more readily flee from an approaching threat. The researchers therefore set out to test whether the distances at which birds fled from their nests on the exposed ground was related to the camouflage of their plumage and eggs.

They found that birds that usually flee from predators at long range, such as plovers and coursers, stayed on their nest for longer when the pattern of their eggs was a better match to the background. They also adjusted their behaviour in the heat of the middle of the day, letting a predator approach a little closer before fleeing. This probably allows them to shade their eggs for as long as possible, and so reduce the chance of them cooking in the African sun. By contrast, another group of birds, the nightjars, usually sit tight as predators approach so that their eggs are concealed by their camouflaged bodies until the last minute. Sure enough, nightjars stayed on their nests longer when the colour and pattern of their own plumage, rather than that of their eggs, was a better match to the background.

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Camouflage really does reduce chances of being eaten

A ground-breaking study has confirmed the long held assumption that camouflage protects animals from the clutches of predators

Date:January 29, 2016

Source:University of Exeter

A ground-breaking study has confirmed the long held assumption that camouflage protects animals from the clutches of predators, and offers insights into the most important aspects of camouflage.

The research, by scientists from the Universities of Exeter and Cambridge, investigated the camouflage of ground-nesting birds in Zambia, using sophisticated digital imaging to demonstrate how they would appear from the perspective of a predator.

The team found that animals or eggs that matched the pattern or contrast of the surrounding landscape were less likely to be eaten by their natural predators.

The study is published in leading journal Scientific Reports on Friday, January 29 2016.

Dr Jolyon Troscianko, lead author of the paper from the University of Exeter's Centre for Ecology and Conservation department said: "We know that animal camouflage has evolved over millions of years to help prey evade being seen by predators - it is a classic example of natural selection.

"Yet although it may seem obvious that blending into your background makes you less likely to be seen, it is surprisingly difficult to test this in a natural setting.

"This is partly because very well camouflaged animals are of course difficult to find in the wild, and also because they tend to keep moving around, meaning the match between their own appearance and their background is constantly changing. In addition we had determine which predators were eating the nests so that we could take into account their different visual systems."

Martin Stevens from Exeter University who, along with Claire Spottiswoode from the University of Cambridge, co-led the project said: "Despite such a long history of research, ours is the first study to directly show how the degree of camouflage an individual has, to the eyes of its predators, directly affects the likelihood of it being seen and eaten in the wild."

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Gravel-camouflaged nests give threatened shorebirds a boost

Date: August 12, 2015

Source: Central Ornithology Publication Office

Summary: When it comes to reproduction, not every individual equally pulls his or her weight. Researchers spent 13 years tracking the reproductive success of individual Snowy Plovers, and more than anything else they considered, the one factor that stood out was whether plovers nested on sandy beaches or gravel bars: gravel provided better camouflage, leading to more successful fledglings, in turn leading to higher lifetime reproductive success for birds that nested at gravel sites.

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Zebra finches use camouflage

BY 

SARAH ZIELINSKI

2:00PM, OCTOBER 8, 2014

Bird’s nests come in a wide variety of shapes and sizes, and they’re built out of all sorts of things. Hummingbirds, for instance, create tiny cups just a couple centimeters wide; sociable weavers in Africa, in contrast, work together to build huge nests more than two meters across that are so heavy they can collapse trees. There are nests built on rocky ledges, in mounds on the ground, high in trees and on the edges of buildings. Bowerbirds even construct their nests as tiny houses decorated with an artistic eye to attract the ladies.

So perhaps it’s not all that surprising the no one had ever investigated whether birds camouflage their nests to protect their eggs against potential predators. It would make sense that they do, but if you were to test it, where would you start?

For Ida Bailey of the University of St. Andrews in Fife, Scotland, and colleagues, the answer was zebra finches. Male finches usually build nests in dense shrubs and layer the outside of the nests with dry grass stems and fine twigs. Predators, usually birds, take a heavy toll on the zebra finches, though. Since birds tend to hunt based on sight rather than smell, camouflaging a nest might work to protect the eggs sequestered inside. And even better, because zebra finches have good color vision, building a camouflaged nest might be possible.

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Camouflaged bird sparks owl hunt at Chatsworth

Popular Peak District photographer Villager Jim has captured the owl’s art of camouflage in this fantastic picture.
As masters of disguise, the owl can only just be spotted waiting for their prey in the early hours at Chatsworth but they could not escape Villager Jim. The creatures used a wall, a tree and a barn doorway as cover.

Villager Jim said the owls are getting used to him now so they don’t fly away.

http://www.matlockmercury.co.uk/news/local/camouflaged-bird-sparks-owl-hunt-at-chatsworth-1-6874098

Quail Really Know Their Camouflage

Jan. 17, 2013 — When it comes to camouflage, ground-nesting Japanese quail are experts. That's based on new evidence published online on January 17 in Current Biology that mother quail "know" the patterning of their own eggs and choose laying spots to hide them best.

"Not only are the eggs camouflaged, but the birds choose to lay their eggs on a substrate that maximizes camouflage," said P. George Lovell of Abertay University and the University of St Andrews. "Furthermore, the maximization seems specific to individual birds."

Karen Spencer, also of University of St Andrews and a co-author, had earlier noticed that female quail lay eggs that vary a lot in appearance, and that those differences are repeatable. Some birds consistently lay eggs covered in dark spots; others have many fewer spots or, in some cases, almost none at all.

That pattern led the researchers to an intriguing idea: that birds might make optimal egg-laying choices based on the special characteristics of their own eggs. To find out, they gave female quail in the lab a choice between four different backgrounds on which to lay their eggs.

Continued:  http://www.sciencedaily.com/releases/2013/01/130117133122.htm