In recent years, experts have discovered more far-reaching effects of vitamin D deficiency. In 2009, researchers from the University of Missouri-Columbia found that insufficient levels of vitamin D are associated with inflammation, an immune system response that can cause fluid buildup and swelling.
1 of 19 Facebook Pinterest. Feeding birds comes naturally when you grow trees and shrubs with nutritious berries. The plants you'll find in this slideshow do double duty: They attract birds and create a beautiful display with their flowers, fall colors, and fruits adding sparkle to your landscape. 2 of 19 Facebook Pinterest.
Cataracts can occur in senior birds, especially parrots. Watch for signs of loss of vision, squinting, or redness of the eye. Unlike humans, in which cataracts often take years to form, cataracts may develop very quickly (within weeks) in some birds and rapidly lead to blindness.