A light left on near the cage at night: what a budgerigar study reveals
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
A screen or a night light left on near the cage in the evening seems harmless enough. A study on budgerigars shows, however, that nighttime exposure to artificial light has measurable effects that go well beyond a simple sleep disturbance. All our cage-setup guidance is gathered under bird accessories.
Contents · 5 sections
What the budgerigar study shows
A study by Malek and Haim, published in 2019 in the journal Integrative Zoology, exposed budgerigars to artificial light at night at varying durations and intensities, compared with complete darkness. The exposed birds showed increased body mass, degraded reproductive success and compromised disease tolerance, with a stronger effect the longer the nighttime exposure lasted — a clear dose-dependent pattern rather than a simple threshold effect.
Why nighttime matters as much as daytime
The day/night cycle regulates physiological functions in birds that go well beyond sleep: reproduction, weight regulation, immune response. Even moderate light during the expected dark period appears sufficient to disrupt these mechanisms, with no visible warning sign for the day-to-day owner.
What this means for the evening setup
- Place the cage away from screens, night lights and streetlights visible through a window, rather than in the main living room if it stays lit late.
- Use an opaque cage cover at a fixed time, rather than simply dimming ambient light, which can still let residual light through.
- Do not confuse this with daytime enrichment lighting: the UV or LED lamps covered in our article on indoor UV lighting for birds concern the daytime, not the night.
A caveat worth keeping in mind
This study covers the budgerigar, a species already widely used as a reference model in avian research; the exact magnitude of the effect may vary across species. The underlying principle is still worth applying broadly: truly complete darkness at night, with no residual light, costs little and carries no documented downside.
Frequently asked questions
Is a dimmed night light an acceptable compromise?
The study did not test a safe minimum threshold: the effect increases with exposure duration, which argues for complete darkness rather than a continuous low light.
Should the cage also be covered during the day to limit light?
No, daytime light exposure remains necessary and beneficial; only exposure during the nighttime rest period is at issue here. Find all our guides on the bird hub.
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This guide is part of Planète Pets’s Birds universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.
