Fly Infestation After Bird in Wall: Blow Flies Temporary, No Chemicals Needed

Baltimore homeowner: bird in wall weeks ago, then gnats, now large black flies swarming. Sticky traps catching many. 8-month-old baby—chemical concerns. Wonders about drywall removal.

Analysis

• Gnats ≠ young flies (fly larvae = maggots, not small flies)
• Large flies = likely blow flies developing on bird carcass
• Flies will disappear when carcass decomposes (days–weeks)
• No continuous breeding without new carcasses

Recommendations

1. Wait—no treatment needed
2. If flies persist >1 week, capture some for Extension ID (free/low cost)
3. No drywall removal, no exterminator, no chemicals

Follow-Up

Gnats unrelated; no concern. Large flies will self-resolve. Extension can ID both if needed.