The ostrich's eye and brain
Claim in the list: An ostrich’s brain is smaller than its eye.
Verification: The general claim is supported by reference and anatomical sources, but it is best stated as a comparison with a single eyeball and its linear size or mass, not the combined volume of both eyes versus the brain. An ostrich eye is about 50 mm in diameter—among the largest of terrestrial animals. The UK Natural History Museum explicitly says an ostrich’s eye is bigger than its brain; an anatomical study measured the eyeball at about 50 mm in diameter.
Conclusion: A single ostrich eyeball can indeed be larger than the brain by linear dimension and heavier; this should not be confused with a volume comparison of both eyes together.