Birds for love

Mercury is a potent toxicant: It disrupts not just human brains but it can change birds’ behaviour and kill their chicks. After extensive research  scientists have shown that mercury also alters the very thing that many backyard birds are known for-their songs.

Emitted by the burning of coal, mercury in the atmosphere has quadrupled since the days before industrialisation. And the amount of methylmercury in animals throughout much of the world is rising, too. There are much fewer songbirds. One reason could be the decline in trees and the pollution on trees and another is the mercury and other organic compounds in the air.. Inn children exposed in the womb, methylmercury causes problems with speech, language development, learning, and memory. And it does the same with bird brains as well. Methylmercury can affect the very motor functions that control speech – something that may have a parallel in the bird world. Around a smelter in northern Europe with a lot of heavy metal pollution, a study of birds found that they knew fewer songs and sang less at sunrise than birds at two less polluted sites.

Rat-killing poisons can cause agonising death not just in rodents, but also the birds that eat them.

Globally, one in eight – more than 1,300 species – are threatened with extinction, and the status of most of those is deteriorating. Humans have relied on them for ages. Imagine forest-dwellers of ancient times, anxious to avoid snakes and big cats, listening for the alarm calls of sharp-sighted, high-flying,birds. Think of medieval sailors, following fish-eating birds to find out where they should throw their nets.

Apart from the joy that disappears from our lives at seeing them and hearing their beautiful songs, birds are indicators of human health. Humans have relied on birds’ superpowers for millennia. Imagine forest-dwellers of ancient times, anxious to avoid snakes and jaguars, listening for the alarm calls of sharp-sighted, high-flying, omnipresent birds. Think of medieval sailors, following fish-eating birds to find out where they should throw their nets.

They are dying only because of chemicals. These same chemicals also may be altering human hormones. A pregnant mother’s load of chemicals passes to her baby while it is still in the womb, with evidence mounting that chemicals can alter development of a baby’s brain and its reproductive and immune systems, leading to lower intelligence, behavioral problems, and reduced fertility.When it comes to chemicals and broad planetary changes, birds have shown us that they are in a unique position to tip us off to health threats. 

When they die of chemical contamination they tell us that we too are dying of the same contaminants.

Most animals, birds and insects line their beds with something soft. The bonehouse wasp lines its cavity “home” with the bodies of dead ants.

 

Breeding for tameness tends to produce animals with floppy ears, patches of white fur, juvenile faces, small jaws and other features, a new study published in the journal Genetics, reports. The researchers believe these features are tied to what they call “domestication syndrome,” which can apply not only to mammals like dogs, foxes, pigs, horses, sheep and rabbits. Scientists, including Charles Darwin, have wondered why domesticated animals seem to have so many features and behaviors in common.

The researchers theorise that domestication with tameness as a goal leads to genetic alterations that can affect a group of embryonic stem cells called the neural crest. Neural crest cells are formed near the developing spinal cord of early vertebrate embryos. As the embryo matures, the cells migrate to different parts of the body and give rise to many tissue types. These tissues include pigment cells and parts of the skull, jaws, teeth, and ears–as well as the adrenal glands which affect responses. Neural crest cells also indirectly affect brain development. Domesticated animals even have smaller brains than their wild counterparts.

When humans bred these animals for tameness, they may have inadvertently selected those with mild neural crest deficits, resulting in smaller or slow-maturing adrenal glands. Because the neural crest influences more than the adrenal glands, the domestication process could also lead to all of the aforementioned physical signs of tameness. They aren’t always beneficial. Floppy ears, for example, may look adorable on dogs and rabbits, but they actually are a result of malformed ear cartilage. An animal hoping to hear well isn’t going to benefit from having the ear flopped down alongside its face.