On December 29, 1946, the American zoologist Edmund Jager and a party of students were on an expedition in the Mojave Desert of southern California.
As the group passed through a small, narrow canyon in the Chuckawalla Mountains, Jager spotted something curious on the wall of a cliff. In one of the numerous weathered shallow hollows no bigger than a hand, sat a bird.
It was a poor-will. Its spotted grey plumage harmonised perfectly with the crystalline structure of the grey granite.
They paused to watch it for about ten minutes. The bird gave not the slightest sign of life. Then Jager stretched out his hand to touch it. He ran his hand down its back several times, but the bird gave no reaction to suggest that there was any life left in it.
The group trudged on. About two hours later, when they came back through the small canyon again, there was the bird, still sitting in the hollow. Its position was unchanged.
This time Jager reached in and took the bird out. It felt unusually light. In fact, it seemed to be dried out. The bird’ s feet and its eyelids, on which a bird's temperature can be felt, were plain cold. Jager concluded that the bird had frozen to death in its place of shelter. He placed the poor-will back in the hollow, then they continued their trek.
Jager mentioned the incident to his friend, Professor Lloyd Smith, who expressed an interest to see this unusual find.
So ten days after his first visit, Jager was back with his friend – and there was the bird, still in the same place, its position unchanged.
One of the men removed it from the niche. Then, as he was holding it to examine it, an amazing thing happened. The poor-will's beak opened, and the bird uttered a few very high-pitched, whimpering, squeaking notes.
And the poor-will’ s eyes opened briefly – or so they both thought. Then suddenly the bird lifted its wings. But the movement looked lifeless and mechanical.
Cautiously, Jager attempted to fold the wings back into their previous position, but he couldn’ t. As soon as he let go, the wings just snapped back, like steel springs, into the lifted position. So he used force, and succeeded finally to lay them flat against the body.
Then Jager placed the bird back into its hollow to remain there as an oddity - something to show future student expeditions. The bird did not look so good after all the handling. The plumage was now tousled and the wings stood at an unnatural angle.
The two scientists went on through the canyon. Passing back two hours later, they saw that nothing had changed. The bird remained in the same unnatural posture into which they had placed it earlier.
However, they thought this would make an interesting camera shot, so they again took the bird from its niche to hold it.
Then something happened that startled them. The poor-will suddenly flew up and away.
The men could hardly believe their eyes. They just stood there watching, as the bird, wings beating rapidly, flew skilfully up along the cliff wall and found itself another rock hollow higher up beyond their reach.
How ever could this be? Had they been witnessing a bird in hibernation, which had been progressively awakened or disturbed by their handling, and had finally had flown away?
We know that during hibernation, the metabolism of animals is sharply reduced. Observations of mammals in hibernation have confirmed that the normal rate of 300 heartbeats a minute declines to just 5 beats. An animal in hibernation has only its pilot light going, so to speak.
But until this incident, hibernation in birds had never been observed.
Almost a year later, at the end of November 1947, Jager came back. And he was fortunate to find the poor-will again, in the very same cliff niche.
On this occasion, he had the opportunity to conduct careful studies. He was able to confirm that a bird – and a desert bird at that - could indeed hibernate.
First, he took the bird's temperature at the anus. The reading was 18 degrees C. (that is 64 degrees F). Since that was higher than the temperature of the surroundings, it proved that the bird was still alive and was actually in hibernation. The normal temperature of this bird is about 42 degrees C. (108 degrees F.), so the poor-will had lowered its body temperature by about 24 degrees C. (44 degrees F).
When the scientist applied a stethoscope to the bird’ s breast it told him nothing. The poor-will’ s heart was beating so slowly and feebly that it could not be heard.
He then placed a cold metal mirror in front of the bird's nostrils. The mirror did not mist over, as would be the case if there was any noticeable breathing.
To determine once and for all if the bird was alive, Jager tried a final experiment. Opening one of the creature’ s eyelids, he flashed a penlight into the pupil of the eye. Again, he observed no reaction. In fact, the bird did not even try to close its eyelid.
But the bird was definitely alive, The measured body temperature proved that.
Every two weeks Jager came back to weigh the bird. The weight was found to be slowly diminishing: 45.61 grams, 45.58 grams, 45.50 grams, 44.56 grams.
These measurements indicated the very slow rate at which the hibernating bird was consuming its reserves of fat. The hibernation continued right through winter – for three months. Then the bird ended its deathlike rigidity, having consumed only 6 grams of fat.
Interestingly, this bird came back to hibernate in the very same hollow in that same cliff for the next two years, 1948 and 1949.
In response to his published report, Jager received many letters reporting similar phenomena.
The Killing of Paradise Planet
- thermonuclear reactor 52-54 - water canopy 30-33,44-47,64,116