“An electrifying discovery!”
“I could set that on fire.”
“It may comfort something but it doesn't comfort me.”
“IT CONTAINS A SPAWNPOINT”
“The nest of those electrical guys.”
“Those birds appear to be incubating deposits of iron!”
“The home of Thor's bird.”
“It's one of the scary bird's nests.”
“It's that owl-dude's home.”
“Any eggs in there?”
“'Tis nature's treasure chest.”
“'TIS HOME OF THE ZAPPY BIRD”
The Thundernest is a naturally-spawning Structure exclusive to Don't Starve: Hamlet DLC. It can be found in the Painted biome with a Thunderbird on the top of it, smoldering it.
If the player gets too close to it, the Thunderbird will strike a set of 3 lightnings, which may hit the player and/or burn any nearby Trees or Tuber Trees. The Thunderbird will then run off its nest, allowing the player to pick the Iron Ore in it.
The iron on the nest itself is non-renewable, unlike other kinds of nests found in the base game such as Tallbird Nests. And, Thunderbirds will spawn after a couple of days if the nest's owner is killed.