Magnesium is involved in over 300 enzymatic reactions in a bird's body and plays structural roles in bone, muscle, and nerve function. About 60% of a bird's magnesium is stored in the skeleton, where it contributes to bone strength alongside calcium and phosphorus. The remaining magnesium is distributed throughout soft tissues, where it is essential for muscle contraction and relaxation, nerve impulse transmission, energy production (ATP metabolism requires magnesium), and protein synthesis.
For the birds at your feeder, magnesium is particularly important during the energetically demanding periods of molt, breeding, and winter survival. During molt, the rapid production of new feathers requires intense protein synthesis, and magnesium-dependent enzymes are involved at every step. During winter, the sustained muscle activity needed for shivering thermogenesis (how small birds generate heat) demands adequate magnesium to keep muscles functioning properly without cramping or fatigue.
Seeds are naturally excellent magnesium sources. Sunflower seeds, pumpkin seeds, peanuts, and millet all contain significant magnesium levels. Because the typical feeder diet is seed-based, magnesium deficiency is very uncommon in birds that visit feeders regularly. The mineral is also present in natural grit and soil particles that ground-feeding birds ingest while foraging.
Any standard seed mix provides ample magnesium. Sunflower seeds are particularly magnesium-rich, providing another reason they are the foundation of any good feeder station. Pumpkin seeds (raw, unsalted) are an excellent magnesium source if you want to add variety — they attract many of the same species that enjoy sunflower, plus some unexpected visitors like grosbeaks.
Muscle tremors, poor coordination, weakness, reduced activity, and in severe cases, convulsions. Magnesium deficiency is very rare in seed-eating wild birds. It would most likely occur in birds with extremely restricted diets or those affected by environmental contamination that interferes with magnesium absorption.
Magnesium excess from dietary sources is not a concern for wild birds. Their kidneys efficiently excrete surplus magnesium. The mineral has a wide safety margin when consumed through natural food sources.
| Life Stage | Size | Min | Max | Unit | Notes |
|---|---|---|---|---|---|
| Adult | — | — | — | mg/kg diet | No established requirement for wild feeder birds. Seeds are naturally magnesium-rich. Any standard seed mix provides adequate magnesium. |
Source: general avian veterinary consensus
