Bats of Gundabad and Dol Guldur
“Soon the thunder passed,
rolling away to the South-East; but the bat-cloud came, flying lower, over the shoulder of the Mountain,
and whirled above them shutting out the light and filling them with dread.”
The Hobbit C17
The Bats of Middle-earth were flying creatures of the night, that tended to roost in caves or dark forests and were apparently quite common in the northern realms. Like many of the creatures, they were corrupted by the Dark Powers and used in war.
It is written in the Red Book of Westmarch that when Bilbo Baggins was walking alone in the tunnels of the Misty Mountains, he heard the whirr of bats about his ears so often that it ceased to startle him. As Bilbo and the dwarves marched through Mirkwood, they gave up lighting fires at night because they attracted thousands of moths, followed by huge black bats. Bilbo encountered yet another bat in Smaug’s lair after the dragon had gone away. This creature, brushing Bilbo’s face, caused the hobbit to stumble and his torch to go out, which brought the dwarves to his rescue. Bats were most famous in Middle-earth for aiding the Goblins during the Battle of Five Armies, in which they flew together over the battlefield so densely no light could be seen between their wings.
In the First Age Thuringwethil was Sauron’s messenger and took the form of a giant bat with great fingered wings. Lúthien would take her form when she and Beren journeyed to Thangorodrim. It is likely that Sauron used these creatures in his breeding programs for Morgoth. Though there were certainly bats in Middle-earth much like the ones in our world, there were also the huge black Vampyre Bats bred by the Dark Powers for use in War,
These vile creatures were written about in the Red Book of Westmarch. These evil bats flew overhead darkening the sky over Bolg’s army of Goblins, as they came down upon the Lonely Mountain. In similar fashion, these huge bats were also said to haunt the skies over Dol Guldur, circling the ruins and ever watching for enemies.
They were over large, ever apt to evil and filled with a dark malice.
Still more suddenly a darkness came on with dreadful swiftness! A black cloud hurried over the sky. Winter thunder on a wild wind rolled roaring up and rumbled in the Mountain, and lightning lit its peak. And beneath the thunder another blackness could be seen whirling forward; but it did not come with the wind, it came from the North, like a vast cloud of birds, so dense that no light could be seen between their wings.
“Halt!” cried Gandalf, who appeared suddenly, and stood alone, with arms uplifted, between the advancing dwarves and the ranks awaiting them. “Halt!” he called in a voice like thunder, and his staff blazed forth with a flash like the lightning. “Dread has come upon you all! Alas! it has come more swiftly than I guessed. The Goblins are upon you! Bolg- of the North is coming, O Dain! whose father you slew in Moria. Behold! the bats are above his army like a sea of locusts. They ride upon wolves and Wargs are in their train!”
Amazement and confusion fell upon them all. Even as Gandalf had been speaking the darkness grew. The dwarves halted and gazed at the sky. The elves cried out with many voices.
“Come!” called Gandalf. “There is yet time for council. Let Dain son of Nain come swiftly to us!”
So began a battle that none had expected; and it was called the Battle of Five Armies, and it was very terrible. Upon one side were the Goblins and the Wild Wolves, and upon the other were Elves and Men and Dwarves. This is how it fell out. Ever since the fall of the Great Goblin of the Misty Mountains the hatred of their race for the dwarves had been rekindled to fury. Messengers had passed to and fro between all their cities, colonies and strongholds; for they resolved now to win the dominion of the North. Tidings they had gathered in secret ways; and in all the mountains there was a forging and an arming. Then they marched and gathered by hill and valley, going ever by tunnel or under dark, until around and beneath the great mountain Gundabad of the North, where was their capital, a vast host was assembled ready to sweep down in time of storm unawares upon the South. Then they learned of the death of Smaug, and joy was in their hearts; and they hastened night after night through the mountains, and came thus at last on a sudden from the North hard on the heels of Dain. Not even the ravens knew of their coming until they came out in the broken lands which divided the Lonely Mountain from the hills behind. How much Gandalf knew cannot be said, but it is plain that he had not expected this sudden assault.
This is the plan that he made in council with the Elven-king and with Bard; and with Dain, for the dwarf-lord now joined them: the Goblins were the foes of all, and at their coming all other quarrels were forgotten. Their only hope was to lure the goblins into the valley between the arms of the Mountain; and themselves to man the great spurs that struck south and east. Yet this would be perilous, if the goblins were in sufficient numbers to overrun the Mountain itself, and so attack them also from behind and above; but there was no time to make any other plan, or to summon any help.
Soon the thunder passed, rolling away to the South-East; but the bat-cloud came, flying lower, over the shoulder of the Mountain, and whirled above them shutting out the light and filling them with dread.
“To the Mountain!” called Bard. “To the Mountain! Let us take our places while there is yet time!”
On the Southern spur, in its lower slopes and in the rocks at its feet, the Elves were set; on the Eastern spur were men and dwarves. But Bard and some of the nimblest of men and elves climbed to the height of the Eastern shoulder to gain a view to the North. Soon they could see the lands before the Mountain’s feet black with a hurrying multitude. Ere long the vanguard swirled round the spur’s end and came rushing into Dale. These were the swiftest wolf-riders, and already their cries and howls rent the air afar. A few brave men were strung before them to make a feint of resistance, and many there fell before the rest drew back and fled to either side. As Gandalf had hoped, the goblin army had gathered behind the resisted vanguard, and poured now in rage into the valley, driving wildly up between the arms of the Mountain, seeking for the foe. Their banners were countless, black and red, and they came on like a tide in fury and disorder.
From The Hobbit in the chapter “The clouds Burst”
Day drew on. The goblins gathered again in the valley. There a host of Wargs came ravening and with them came the bodyguard of Bolg, goblins of huge size with scimitars of steel. Soon actual darkness was coming into a stormy sky; while still the great bats swirled about the heads and ears of elves and men, or fastened vampire-like on the stricken. Now Bard was fighting to defend the Eastern spur, and yet giving slowly back; and the elf-lords were at bay about their king upon the southern arm, near to the watch-post on Ravenhill.
From The Hobbit in the chapter “The clouds Burst”