SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/bird-unfiltered-light

Why is sunlight through a closed window not the same as unfiltered sunlight?

Window glass blocks needed ultraviolet rays.

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  1. Glass adds too much heat only
  2. Glass makes light too colorful
  3. Glass blocks needed UV rays ✔

Why: Birds need UVA and UVB exposure from safe unfiltered sunlight or suitable full-spectrum lighting. The University of Florida notes that ordinary window glass blocks needed UV rays.

Huh, didn't know that: The University of Florida suggests daily unfiltered sunlight, full-spectrum lighting, or both.

The dad joke
Why did the bird study the window? It wanted to shed light on the glass.
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References

Answer: Glass blocks needed UV rays. Birds need UVA and UVB exposure from safe unfiltered sunlight or suitable full-spectrum lighting. The University of Florida notes that ordinary window glass blocks needed UV rays.

  1. University of Florida Small Animal Hospital, Pet Bird Care smallanimal.vethospital.ufl.edu/clinical-services/zoological-medicine/how-to-care-for-your-pet-bird
    Window glass blocks necessary UV rays.
    Checked 2026-10-11.

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