Lead-containing metals are everywhere — loose wires, linoleum, paint, twist ties, soldering and zippers, to name a few, and birds love to nosh on them.

Persin, a compound found in avocado leaves, has caused several bird species to experience respiratory distress, heart failure and even death. While avocado appears to be tolerated by many birds, some birds appear to have a sensitivity that should be noted.

Certain fruit seeds, such as apples and pears, or pits, like those from cherries and plums, contain cardio-toxic cyanide, a substance that's poison to birds' systems.

When certain non-stick surfaces are heated, they emit vapors that, when inhaled by birds, can cause instant death.

Caffeine in coffee, tea and certain soft drinks can be harmful to your bird, even in small amounts.

Chocolate contains theobromine, which can cause similar symptoms to caffeine, causing an increased heart rate, tremors and potential death.

Birds love salt, often found in popcorn, chips and crackers, but it can cause serious damage to a small bird's electrolyte balance.

While xylitol, an artificial sweetener, hasn't been studied for safety in birds, it causes life-threatening problems in dogs, so it's best not to take chances.

Compounds such as allicin and sulfur in onions and garlic may be toxic to birds in high quantities and cause changes to their red blood cells if consumed in excess.

Birds inhale and exhale simultaneously with every breath, so they're extremely sensitive to aerosols from hairspray and oven cleaner, for example, as well as cigarette smoke.

All room sprays, deodorizers, plug-ins, synthetically fragranced candles and incense should not be used in homes where birds live.