Why are there no poisonous birds?
Kind of need teeth for that. Bony tails (like scorpions) would work I suppose, but might mess up their flight capabilities.
Then again, cockatrices and wyverns, yo!
According to copilot, there are poisonous birds, but they are rare and they are not venomous.
QuoteContrary to the premise of your question, scientists have identified a small number of birds that are chemically toxic.
The best-known example is the hooded pitohui from Papua New Guinea.
Its skin and feathers contain batrachotoxin, a powerful neurotoxin that can cause numbness or tingling if touched.
Other examples include:
Blue-capped ifrit
European quail (occasionally toxic to eat)
Spur-winged goose
Overall, this is an exceptional trait among birds, not a common one.
Even though toxicity exists, it's unusual in birds compared to insects, amphibians, or reptiles. The reasons come down to evolutionary trade-offs:
(A) Birds already have extremely effective defenses
Birds evolved different survival strategies:
Flight (escape predators)
Speed and mobility
Sharp beaks/talons (in many species)
Because these strategies are effective, there's less evolutionary pressure to develop toxins.
(B) Toxins are metabolically costly
Producing or handling toxins is biologically expensive:
Requires specialized physiology
Requires resistance to self-poisoning
Many animals evolve toxins only when they need them (e.g., slow, vulnerable animals). Birds generally don't fall into that category.
(C) Most toxic birds don't make their own poison
A key limitation:
Known poisonous birds don't synthesize toxins themselves
They acquire them from diet (e.g., toxic beetles) [en.wikipedia.org]
That means:
The trait depends on ecology, not just genetics
It's harder to evolve widely across bird species
(D) Toxicity evolved only in a few isolated lineages
Research shows:
Toxicity in birds arose independently in small clusters
Many lineages may have gained and then lost it over time [en.wikipedia.org]
So it never became a widespread "successful" strategy in birds.
(https://static01.nyt.com/images/2022/02/09/podcasts/09DAILY-birds-arent-real-audio-app/09DAILY-birds-arent-real-audio-app-superJumbo.jpg)