Iron containing short nerve branches in the upper beak of birds may serve as a magnetometer to measure the vector of the Earth magnetic field (intensity and inclination) and not only as a magnetic compass, which shows the direction of the magnetic field lines. Whether this magnetic map is consulted, strongly depends on the avian species and its current motivation to do so...research has...suggested that magnetic compass and magnetic map sense are based on different mechanisms and are localized at different sites: The magnetic compass resides in the eye, the magnetometer for the magnetic map lies in the beak.
Dr. Gerta Fleissner
So that's it then, lovebird of mine:
our eyes alone won't do it. Point A
to B, I see it, sure,
but won't find my way to it.
I'll fly and fight and never tire
until this ocean's crossed;
but 'til we're mouth
to mouth, my dear, I'll be
as good as lost.
original bird-compass article here.
photograph by Claire
It is no night to drown in:
A full moon, river lapsing
Black beneath bland mirror-sheen,
The blue water-mists dropping
Scrim after scrim like fishnets
Though fishermen are sleeping,
The massive castle turrets
Doubling themselves in a glass
All stillness. Yet these shapes float
Up toward me, troubling the face
Of quiet. From the nadir
They rise, their limbs ponderous
With richness, hair heavier
Than sculptured marble. They sing
Of a world more full and clear
Than can be. Sisters, your song
Bears a burden too weighty
For the whorled ear's listening
Here, in a well-steered country,
Under a balanced ruler.
Deranging by harmony
Beyond the mundane order,
Your voices lay siege. You lodge
On the pitched reefs of nightmare,
Promising sure harborage;
By day, descant from borders
Of hebetude, from the ledge
Also of high windows. Worse
Even than your maddening
Song, your silence. At the source
Of your ice-hearted calling --
Drunkenness of the great depths.
O river, I see drifting
Deep in your flux of silver
Those great goddesses of peace.
Stone, stone, ferry me down there.
Sylvia Plath (October 27, 1932 – February 11, 1963)
illustration by Arthur Rackham