---
id: kb-2026-00497
title: Birds
schema_type: TechArticle
category: science
language: en
confidence: medium
last_verified: '2026-05-28'
created_date: '2026-05-22'
generation_method: ai_assisted
ai_models:
  - claude-opus
derived_from_human_seed: true
conflict_of_interest: none_declared
is_live_document: false
data_period: static
atomic_facts:
  - id: fact-science-001
    statement: >-
      Britannica describes birds as warm-blooded vertebrates of class Aves, distinguished by
      feathers.
    source_title: Bird
    source_url: https://www.britannica.com/animal/bird-animal
    confidence: medium
  - id: fact-science-002
    statement: >-
      Cornell Lab of Ornithology explains that feathers help birds with flight, insulation,
      waterproofing, display, and camouflage.
    source_title: All About Feathers
    source_url: https://academy.allaboutbirds.org/features/all-about-feathers/
    confidence: medium
  - id: fact-science-003
    statement: >-
      Britannica defines animal migration as regular, usually seasonal movement away from and back
      to a given area.
    source_title: Migration
    source_url: https://www.britannica.com/science/migration-animal
    confidence: medium
completeness: 0.88
known_gaps:
  - >-
    Coverage intentionally narrowed to directly sourced public evidence; adjacent subtopics are not
    exhaustively covered.
disputed_statements: []
primary_sources:
  - title: Bird
    type: reference
    year: 2026
    url: https://www.britannica.com/animal/bird-animal
    institution: Encyclopaedia Britannica
  - title: All About Feathers
    type: educational_reference
    year: 2026
    url: https://academy.allaboutbirds.org/features/all-about-feathers/
    institution: Cornell Lab of Ornithology
  - title: Migration
    type: reference
    year: 2026
    url: https://www.britannica.com/science/migration-animal
    institution: Encyclopaedia Britannica
secondary_sources: []
updated: '2026-05-28'
---
## TL;DR

Birds are feathered vertebrates in class Aves. The repaired article avoids unsupported species counts and extreme examples unless directly sourced, focusing on defining traits, feathers, and migration.

## Core Explanation

The stable overview is that birds are distinguished by feathers and other anatomical traits, that feathers support flight, insulation, and signaling functions, and that migration is a recurrent movement pattern used by many species in response to seasonal or ecological pressures.

## Further Reading

- [Bird](https://www.britannica.com/animal/bird-animal)
- [All About Feathers](https://academy.allaboutbirds.org/features/all-about-feathers/)
- [Migration](https://www.britannica.com/science/migration-animal)