Sunshine and Vitamin D in the Blue Mountains

By Dr TD

​Springwood, maximum 13 degrees. Brrrr!

Who wants to put their pet birds outside in winter? In the mountains? You'd have to be crazy, right?

Actually, you'd be crazy not to. And that's because of the importance of direct sunlight to your bird's vitamin D levels.

Vitamin D is essential for the absorption and utilisation of minerals including calcium. Human residents of the Blue Mountains may be used to their GP's exhortation to get more sun, especially in winter. Without enough vitamin D, laying birds can show reduced eggshell thickness or eggs with no shell at all. Growing birds can show osteodystrophy. All can show clinical signs of hypocalcaemia including seizures, and soft bones prone to deformity or fracture.

Backyard chooks will usually get plenty of direct sun. When it comes to caged birds, however, setting their cage near a window won't quite be good enough, since it's the ultraviolet part of the spectrum they need, which can be filtered out by the glass.

UV-B converts provitamin D in the skin to cholecalciferol, or Vitamin D3. If it's really freezing outside, could you use UV-B fluorescent bulbs for some fake sun therapy? Absolutely! 30 minutes of direct sunlight per day should be sufficient.

Couldn't you just supplement with vitamin D in water or food instead? This can be tricky when it comes to under- or over- dosing. Macaws can get vitamin D toxicity (mineralised kidneys) at lower levels than other birds (1000 IU/kg). Dosages vary, and many formulated diets already contain extra fat-soluble vitamins including vitamin D.

Ideally, regulation of calcium and vitamin D would happen with variety in the diet, optional grit available at all times, and plenty of direct sun. It is possible to get vitamin D toxicity by oversupplementing, but not via too much UV-B! (Sunburn remains possible, keep in mind).

Whether you go for the UV-B lamp or the wintry mountain sunshine, taking care of your bird's bones will be worth it. Happy solstice!